Compare commits

..

12 Commits

Author SHA1 Message Date
Ana María Martínez Gómez
c547519ee4 Merge pull request #537 from Ana06/master-py2-1_6_3 2021-04-29 14:13:20 +02:00
Ana Maria Martinez Gomez
b65286a435 changelog: v1.6.3
- Add v1.6.3 to changelog
- Remove capa rules from v1.6.2 (there were no changes). I'll remove the
tag in capa-rules once this is merged.
- Remove master (unreleased) section. This only makes sense in master
and we are only using this branch for backporting bug fixes.
2021-04-29 11:56:50 +02:00
Ana Maria Martinez Gomez
3eef5c8773 version: bump to v1.6.3 2021-04-29 11:56:50 +02:00
Ana Maria Martinez Gomez
f70b046ed4 ci: update isort
Before removing Py2 we were already using isort 3.8.0 in the tests, as
we were requiring isort 5 explicitly:
```
pip install 'isort==5.*' black
```
ce8370931e starts using the setup.py
version, which makes the tests fail.

Note this was not a problem because we were using Py3 for the code
linters.
2021-04-29 11:56:50 +02:00
William Ballenthin
ce8370931e ci: use black/isort dep from setup.py
closes #535
2021-04-29 11:38:14 +02:00
Ana Maria Martinez Gomez
8f58ccc8ae doc: document support IDA versions
Text taken from master (except the Python version).
2021-04-29 11:18:51 +02:00
Willi Ballenthin
92cd6c6726 ida: support 7.6
closes #496
2021-04-29 11:12:36 +02:00
Ana María Martínez Gómez
eea0e1e738 Merge pull request #527 from Ana06/v1-6-2 2021-04-13 17:21:31 +02:00
Ana Maria Martinez Gomez
60834e3ecd changelog: v1.6.2
This release backports a fix to capa 1.6: The Windows binary was built
with Python 3.9 which doesn't support Windows 7.
2021-04-13 12:18:50 +02:00
Ana Maria Martinez Gomez
54f8f6d162 version: bump to v1.6.2 2021-04-13 12:16:19 +02:00
Ana Maria Martinez Gomez
62743e1363 ci: Enable tests for master-py2 branch
Use the master-py branch to backport fixes to capa 1.6 (Python 2
support).
2021-04-13 12:08:30 +02:00
Ana Maria Martinez Gomez
b34d791d05 build: Fix binary for Windows 7
Python 3.9 doesn't support Windows 7. Build with Python 3.8 instead.
2021-04-13 12:06:05 +02:00
200 changed files with 7659 additions and 28766 deletions

View File

@@ -1,21 +0,0 @@
# See here for image contents: https://github.com/microsoft/vscode-dev-containers/tree/v0.233.0/containers/python-3/.devcontainer/base.Dockerfile
# [Choice] Python version (use -bullseye variants on local arm64/Apple Silicon): 3, 3.10, 3.9, 3.8, 3.7, 3.6, 3-bullseye, 3.10-bullseye, 3.9-bullseye, 3.8-bullseye, 3.7-bullseye, 3.6-bullseye, 3-buster, 3.10-buster, 3.9-buster, 3.8-buster, 3.7-buster, 3.6-buster
ARG VARIANT="3.10-bullseye"
FROM mcr.microsoft.com/vscode/devcontainers/python:0-${VARIANT}
# [Choice] Node.js version: none, lts/*, 16, 14, 12, 10
ARG NODE_VERSION="none"
RUN if [ "${NODE_VERSION}" != "none" ]; then su vscode -c "umask 0002 && . /usr/local/share/nvm/nvm.sh && nvm install ${NODE_VERSION} 2>&1"; fi
# [Optional] If your pip requirements rarely change, uncomment this section to add them to the image.
# COPY requirements.txt /tmp/pip-tmp/
# RUN pip3 --disable-pip-version-check --no-cache-dir install -r /tmp/pip-tmp/requirements.txt \
# && rm -rf /tmp/pip-tmp
# [Optional] Uncomment this section to install additional OS packages.
# RUN apt-get update && export DEBIAN_FRONTEND=noninteractive \
# && apt-get -y install --no-install-recommends <your-package-list-here>
# [Optional] Uncomment this line to install global node packages.
# RUN su vscode -c "source /usr/local/share/nvm/nvm.sh && npm install -g <your-package-here>" 2>&1

View File

@@ -1,51 +0,0 @@
// For format details, see https://aka.ms/devcontainer.json. For config options, see the README at:
// https://github.com/microsoft/vscode-dev-containers/tree/v0.233.0/containers/python-3
{
"name": "Python 3",
"build": {
"dockerfile": "Dockerfile",
"context": "..",
"args": {
// Update 'VARIANT' to pick a Python version: 3, 3.10, 3.9, 3.8, 3.7, 3.6
// Append -bullseye or -buster to pin to an OS version.
// Use -bullseye variants on local on arm64/Apple Silicon.
"VARIANT": "3.10",
// Options
"NODE_VERSION": "none"
}
},
// Set *default* container specific settings.json values on container create.
"settings": {
"python.defaultInterpreterPath": "/usr/local/bin/python",
"python.linting.enabled": true,
"python.linting.pylintEnabled": true,
"python.formatting.autopep8Path": "/usr/local/py-utils/bin/autopep8",
"python.formatting.blackPath": "/usr/local/py-utils/bin/black",
"python.formatting.yapfPath": "/usr/local/py-utils/bin/yapf",
"python.linting.banditPath": "/usr/local/py-utils/bin/bandit",
"python.linting.flake8Path": "/usr/local/py-utils/bin/flake8",
"python.linting.mypyPath": "/usr/local/py-utils/bin/mypy",
"python.linting.pycodestylePath": "/usr/local/py-utils/bin/pycodestyle",
"python.linting.pydocstylePath": "/usr/local/py-utils/bin/pydocstyle",
"python.linting.pylintPath": "/usr/local/py-utils/bin/pylint"
},
// Add the IDs of extensions you want installed when the container is created.
"extensions": [
"ms-python.python",
"ms-python.vscode-pylance"
],
// Use 'forwardPorts' to make a list of ports inside the container available locally.
// "forwardPorts": [],
// Use 'postCreateCommand' to run commands after the container is created.
"postCreateCommand": "git submodule update --init && pip3 install --user -e .[dev] && pre-commit install",
// Comment out to connect as root instead. More info: https://aka.ms/vscode-remote/containers/non-root.
"remoteUser": "vscode",
"features": {
"git": "latest"
}
}

View File

@@ -2,7 +2,7 @@
First off, thanks for taking the time to contribute!
The following is a set of guidelines for contributing to capa and its packages, which are hosted in the [Mandiant Organization](https://github.com/mandiant) on GitHub. These are mostly guidelines, not rules. Use your best judgment, and feel free to propose changes to this document in a pull request.
The following is a set of guidelines for contributing to capa and its packages, which are hosted in the [FireEye Organization](https://github.com/fireeye) on GitHub. These are mostly guidelines, not rules. Use your best judgment, and feel free to propose changes to this document in a pull request.
#### Table Of Contents
@@ -31,10 +31,10 @@ This project and everyone participating in it is governed by the [Capa Code of C
### Capa and its repositories
We host the capa project as three GitHub repositories:
- [capa](https://github.com/mandiant/capa)
- [capa-rules](https://github.com/mandiant/capa-rules)
- [capa-testfiles](https://github.com/mandiant/capa-testfiles)
We host the capa project as three Github repositories:
- [capa](https://github.com/fireeye/capa)
- [capa-rules](https://github.com/fireeye/capa-rules)
- [capa-testfiles](https://github.com/fireeye/capa-testfiles)
The command line tools, logic engine, and other Python source code are found in the `capa` repository.
This is the repository to fork when you want to enhance the features, performance, or user interface of capa.
@@ -54,7 +54,7 @@ These are files you'll need in order to run the linter (in `--thorough` mode) an
### Design Decisions
When we make a significant decision in how we maintain the project and what we can or cannot support,
we will document it in the [capa issues tracker](https://github.com/mandiant/capa/issues).
we will document it in the [capa issues tracker](https://github.com/fireeye/capa/issues).
This is the best place review our discussions about what/how/why we do things in the project.
If you have a question, check to see if it is documented there.
If it is *not* documented there, or you can't find an answer, please open a issue.
@@ -78,7 +78,7 @@ Fill out [the required template](./ISSUE_TEMPLATE/bug_report.md),
#### Before Submitting A Bug Report
* **Determine [which repository the problem should be reported in](#capa-and-its-repositories)**.
* **Perform a [cursory search](https://github.com/mandiant/capa/issues?q=is%3Aissue)** to see if the problem has already been reported. If it has **and the issue is still open**, add a comment to the existing issue instead of opening a new one.
* **Perform a [cursory search](https://github.com/fireeye/capa/issues?q=is%3Aissue)** to see if the problem has already been reported. If it has **and the issue is still open**, add a comment to the existing issue instead of opening a new one.
#### How Do I Submit A (Good) Bug Report?
@@ -101,7 +101,7 @@ Explain the problem and include additional details to help maintainers reproduce
Provide more context by answering these questions:
* **Did the problem start happening recently** (e.g. after updating to a new version of capa) or was this always a problem?
* If the problem started happening recently, **can you reproduce the problem in an older version of capa?** What's the most recent version in which the problem doesn't happen? You can download older versions of capa from [the releases page](https://github.com/mandiant/capa/releases).
* If the problem started happening recently, **can you reproduce the problem in an older version of capa?** What's the most recent version in which the problem doesn't happen? You can download older versions of capa from [the releases page](https://github.com/fireeye/capa/releases).
* **Can you reliably reproduce the issue?** If not, provide details about how often the problem happens and under which conditions it normally happens.
* If the problem is related to working with files (e.g. opening and editing files), **does the problem happen for all files and projects or only some?** Does the problem happen only when working with local or remote files (e.g. on network drives), with files of a specific type (e.g. only JavaScript or Python files), with large files or files with very long lines, or with files in a specific encoding? Is there anything else special about the files you are using?
@@ -119,7 +119,7 @@ Before creating enhancement suggestions, please check [this list](#before-submit
#### Before Submitting An Enhancement Suggestion
* **Determine [which repository the enhancement should be suggested in](#capa-and-its-repositories).**
* **Perform a [cursory search](https://github.com/mandiant/capa/issues?q=is%3Aissue)** to see if the enhancement has already been suggested. If it has, add a comment to the existing issue instead of opening a new one.
* **Perform a [cursory search](https://github.com/fireeye/capa/issues?q=is%3Aissue)** to see if the enhancement has already been suggested. If it has, add a comment to the existing issue instead of opening a new one.
#### How Do I Submit A (Good) Enhancement Suggestion?
@@ -138,15 +138,15 @@ Enhancement suggestions are tracked as [GitHub issues](https://guides.github.com
Unsure where to begin contributing to capa? You can start by looking through these `good-first-issue` and `rule-idea` issues:
* [good-first-issue](https://github.com/mandiant/capa/issues?q=is%3Aissue+is%3Aopen+label%3A%22good+first+issue%22) - issues which should only require a few lines of code, and a test or two.
* [rule-idea](https://github.com/mandiant/capa-rules/issues?q=is%3Aissue+is%3Aopen+label%3A%22rule+idea%22) - issues that describe potential new rule ideas.
* [good-first-issue](https://github.com/fireeye/capa/issues?q=is%3Aissue+is%3Aopen+label%3A%22good+first+issue%22) - issues which should only require a few lines of code, and a test or two.
* [rule-idea](https://github.com/fireeye/capa-rules/issues?q=is%3Aissue+is%3Aopen+label%3A%22rule+idea%22) - issues that describe potential new rule ideas.
Both issue lists are sorted by total number of comments. While not perfect, number of comments is a reasonable proxy for impact a given change will have.
#### Local development
capa and all its resources can be developed locally.
For instructions on how to do this, see the "Method 3" section of the [installation guide](https://github.com/mandiant/capa/blob/master/doc/installation.md).
For instructions on how to do this, see the "Method 3" section of the [installation guide](https://github.com/fireeye/capa/blob/master/doc/installation.md).
### Pull Requests
@@ -159,25 +159,12 @@ The process described here has several goals:
Please follow these steps to have your contribution considered by the maintainers:
0. Sign the [Contributor License Agreement](#contributor-license-agreement)
1. Follow the [styleguides](#styleguides)
2. Update the CHANGELOG and add tests and documentation. In case they are not needed, indicate it in [the PR template](pull_request_template.md).
1. Follow all instructions in [the template](PULL_REQUEST_TEMPLATE.md)
2. Follow the [styleguides](#styleguides)
3. After you submit your pull request, verify that all [status checks](https://help.github.com/articles/about-status-checks/) are passing <details><summary>What if the status checks are failing? </summary>If a status check is failing, and you believe that the failure is unrelated to your change, please leave a comment on the pull request explaining why you believe the failure is unrelated. A maintainer will re-run the status check for you. If we conclude that the failure was a false positive, then we will open an issue to track that problem with our status check suite.</details>
While the prerequisites above must be satisfied prior to having your pull request reviewed, the reviewer(s) may ask you to complete additional design work, tests, or other changes before your pull request can be ultimately accepted.
### Contributor License Agreement
Contributions to this project must be accompanied by a Contributor License
Agreement. You (or your employer) retain the copyright to your contribution,
this simply gives us permission to use and redistribute your contributions as
part of the project. Head over to <https://cla.developers.google.com/> to see
your current agreements on file or to sign a new one.
You generally only need to submit a CLA once, so if you've already submitted one
(even if it was for a different project), you probably don't need to do it
again.
## Styleguides
### Git Commit Messages
@@ -203,8 +190,8 @@ Our CI pipeline will reformat and enforce the Python styleguide.
All (non-nursery) capa rules must:
1. pass the [linter](https://github.com/mandiant/capa/blob/master/scripts/lint.py), and
2. be formatted with [capafmt](https://github.com/mandiant/capa/blob/master/scripts/capafmt.py)
1. pass the [linter](https://github.com/fireeye/capa/blob/master/scripts/lint.py), and
2. be formatted with [capafmt](https://github.com/fireeye/capa/blob/master/scripts/capafmt.py)
This ensures that all rules meet the same minimum level of quality and are structured in a consistent way.
Our CI pipeline will reformat and enforce the capa rules styleguide.

View File

@@ -5,16 +5,16 @@ about: Create a report to help us improve
---
<!--
# Is your bug report related to capa rules (for example a false positive)?
We use submodules to separate code, rules and test data. If your issue is related to capa rules, please report it at https://github.com/mandiant/capa-rules/issues.
We use submodules to separate code, rules and test data. If your issue is related to capa rules, please report it at https://github.com/fireeye/capa-rules/issues.
# Have you checked that your issue isn't already filed?
Please search if there is a similar issue at https://github.com/mandiant/capa/issues. If there is already a similar issue, please add more details there instead of opening a new one.
Please search if there is a similar issue at https://github.com/fireeye/capa/issues. If there is already a similar issue, please add more details there instead of opening a new one.
# Have you read capa's Code of Conduct?
By filing an Issue, you are expected to comply with it, including treating everyone with respect: https://github.com/mandiant/capa/blob/master/.github/CODE_OF_CONDUCT.md
By filing an Issue, you are expected to comply with it, including treating everyone with respect: https://github.com/fireeye/capa/blob/master/.github/CODE_OF_CONDUCT.md
# Have you read capa's CONTRIBUTING guide?
It contains helpful information about how to contribute to capa. Check https://github.com/mandiant/capa/blob/master/.github/CONTRIBUTING.md#reporting-bugs
It contains helpful information about how to contribute to capa. Check https://github.com/fireeye/capa/blob/master/.github/CONTRIBUTING.md#reporting-bugs
-->
### Description

View File

@@ -5,16 +5,16 @@ about: Suggest an idea for capa
---
<!--
# Is your issue related to capa rules (for example an idea for a new rule)?
We use submodules to separate code, rules and test data. If your issue is related to capa rules, please report it at https://github.com/mandiant/capa-rules/issues.
We use submodules to separate code, rules and test data. If your issue is related to capa rules, please report it at https://github.com/fireeye/capa-rules/issues.
# Have you checked that your issue isn't already filed?
Please search if there is a similar issue at https://github.com/mandiant/capa/issues. If there is already a similar issue, please add more details there instead of opening a new one.
Please search if there is a similar issue at https://github.com/fireeye/capa/issues. If there is already a similar issue, please add more details there instead of opening a new one.
# Have you read capa's Code of Conduct?
By filing an Issue, you are expected to comply with it, including treating everyone with respect: https://github.com/mandiant/capa/blob/master/.github/CODE_OF_CONDUCT.md
By filing an Issue, you are expected to comply with it, including treating everyone with respect: https://github.com/fireeye/capa/blob/master/.github/CODE_OF_CONDUCT.md
# Have you read capa's CONTRIBUTING guide?
It contains helpful information about how to contribute to capa. Check https://github.com/mandiant/capa/blob/master/.github/CONTRIBUTING.md#suggesting-enhancements
It contains helpful information about how to contribute to capa. Check https://github.com/fireeye/capa/blob/master/.github/CONTRIBUTING.md#suggesting-enhancements
-->
### Summary

41
.github/flake8.ini vendored
View File

@@ -1,41 +0,0 @@
[flake8]
max-line-length = 120
extend-ignore =
# E203: whitespace before ':' (black does this)
E203,
# F401: `foo` imported but unused (prefer ruff)
F401,
# F811 Redefinition of unused `foo` (prefer ruff)
F811,
# E501 line too long (prefer black)
E501,
# B010 Do not call setattr with a constant attribute value
B010,
# G200 Logging statement uses exception in arguments
G200,
# SIM102 Use a single if-statement instead of nested if-statements
# doesn't provide a space for commenting or logical separation of conditions
SIM102,
# SIM114 Use logical or and a single body
# makes logic trees too complex
SIM114,
# SIM117 Use 'with Foo, Bar:' instead of multiple with statements
# makes lines too long
SIM117
per-file-ignores =
# T201 print found.
#
# scripts are meant to print output
scripts/*: T201
# capa.exe is meant to print output
capa/main.py: T201
# IDA tests emit results to output window so need to print
tests/test_ida_features.py: T201
# utility used to find the Binary Ninja API via invoking python.exe
capa/features/extractors/binja/find_binja_api.py: T201
copyright-check = True
copyright-min-file-size = 1
copyright-regexp = Copyright \(C\) 2023 Mandiant, Inc. All Rights Reserved.

91
.github/mypy/mypy.ini vendored
View File

@@ -1,91 +0,0 @@
[mypy]
[mypy-halo.*]
ignore_missing_imports = True
[mypy-tqdm.*]
ignore_missing_imports = True
[mypy-ruamel.*]
ignore_missing_imports = True
[mypy-networkx.*]
ignore_missing_imports = True
[mypy-pefile.*]
ignore_missing_imports = True
[mypy-viv_utils.*]
ignore_missing_imports = True
[mypy-flirt.*]
ignore_missing_imports = True
[mypy-lief.*]
ignore_missing_imports = True
[mypy-idc.*]
ignore_missing_imports = True
[mypy-vivisect.*]
ignore_missing_imports = True
[mypy-envi.*]
ignore_missing_imports = True
[mypy-PE.*]
ignore_missing_imports = True
[mypy-idaapi.*]
ignore_missing_imports = True
[mypy-idautils.*]
ignore_missing_imports = True
[mypy-ida_auto.*]
ignore_missing_imports = True
[mypy-ida_bytes.*]
ignore_missing_imports = True
[mypy-ida_nalt.*]
ignore_missing_imports = True
[mypy-ida_kernwin.*]
ignore_missing_imports = True
[mypy-ida_settings.*]
ignore_missing_imports = True
[mypy-ida_funcs.*]
ignore_missing_imports = True
[mypy-ida_loader.*]
ignore_missing_imports = True
[mypy-ida_segment.*]
ignore_missing_imports = True
[mypy-PyQt5.*]
ignore_missing_imports = True
[mypy-binaryninja.*]
ignore_missing_imports = True
[mypy-pytest.*]
ignore_missing_imports = True
[mypy-devtools.*]
ignore_missing_imports = True
[mypy-elftools.*]
ignore_missing_imports = True
[mypy-dncil.*]
ignore_missing_imports = True
[mypy-netnode.*]
ignore_missing_imports = True
[mypy-ghidra.*]
ignore_missing_imports = True

View File

@@ -1,22 +1,32 @@
<!--
Thank you for contributing to capa! <3
Thank you for contributing to capa! :heart:
IMPORTANT NOTE
It's most important that you submit your improvements. So even if you don't use this complete template we look forward to collaborating!
Please read capa's CONTRIBUTING guide if you haven't done so already.
It contains helpful information about how to contribute to capa. Check https://github.com/mandiant/capa/blob/master/.github/CONTRIBUTING.md
It contains helpful information about how to contribute to capa. Check https://github.com/fireeye/capa/blob/master/.github/CONTRIBUTING.md
Please describe the changes in this pull request (PR). Include your motivation and context to help us review.
Please mention the issue your PR addresses (if any):
closes #issue_number
PR template based on https://embeddedartistry.com/blog/2017/08/04/a-github-pull-request-template-for-your-projects/
-->
### Description
### Checklist
<!-- Please describe the changes in this PR. Including your motivation and context helps us to review. -->
<!-- CHANGELOG.md has a `master (unreleased)` section. Please add bug fixes, new features, breaking changes and anything else you think is worthwhile mentioning in the release notes to this file. -->
- [ ] No CHANGELOG update needed
<!-- Tests prove that your fix/work as expected and ensure it doesn't break on the feature. -->
closes # (issue)
### Type of change
Please update the [CHANGELOG.md](/CHANGELOG.md)
- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
- [ ] This change requires a documentation update
- [ ] I have made the corresponding changes to the documentation
### Tests
- [ ] I have added tests that prove my fix is effective or that my feature works
- [ ] No new tests needed
<!-- Please help us keeping capa documentation up-to-date -->
- [ ] No documentation update needed

View File

@@ -0,0 +1,5 @@
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
import PyInstaller.utils.hooks
# ref: https://groups.google.com/g/pyinstaller/c/amWi0-66uZI/m/miPoKfWjBAAJ
binaries = PyInstaller.utils.hooks.collect_dynamic_libs("capstone")

View File

@@ -1,4 +1,4 @@
# Copyright (C) 2020 Mandiant, Inc. All Rights Reserved.
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
from PyInstaller.utils.hooks import copy_metadata
@@ -38,36 +38,39 @@ hiddenimports = [
"vivisect",
"vivisect.analysis",
"vivisect.analysis.amd64",
"vivisect.analysis.amd64",
"vivisect.analysis.amd64.emulation",
"vivisect.analysis.amd64.golang",
"vivisect.analysis.crypto",
"vivisect.analysis.crypto",
"vivisect.analysis.crypto.constants",
"vivisect.analysis.elf",
"vivisect.analysis.elf",
"vivisect.analysis.elf.elfplt",
"vivisect.analysis.elf.elfplt_late",
"vivisect.analysis.elf.libc_start_main",
"vivisect.analysis.generic",
"vivisect.analysis.generic",
"vivisect.analysis.generic.codeblocks",
"vivisect.analysis.generic.emucode",
"vivisect.analysis.generic.entrypoints",
"vivisect.analysis.generic.funcentries",
"vivisect.analysis.generic.impapi",
"vivisect.analysis.generic.linker",
"vivisect.analysis.generic.mkpointers",
"vivisect.analysis.generic.noret",
"vivisect.analysis.generic.pointers",
"vivisect.analysis.generic.pointertables",
"vivisect.analysis.generic.relocations",
"vivisect.analysis.generic.strconst",
"vivisect.analysis.generic.switchcase",
"vivisect.analysis.generic.symswitchcase",
"vivisect.analysis.generic.thunks",
"vivisect.analysis.generic.noret",
"vivisect.analysis.i386",
"vivisect.analysis.i386",
"vivisect.analysis.i386.calling",
"vivisect.analysis.i386.golang",
"vivisect.analysis.i386.importcalls",
"vivisect.analysis.i386.instrhook",
"vivisect.analysis.i386.thunk_reg",
"vivisect.analysis.i386.thunk_bx",
"vivisect.analysis.ms",
"vivisect.analysis.ms",
"vivisect.analysis.ms.hotpatch",
"vivisect.analysis.ms.localhints",
@@ -78,40 +81,8 @@ hiddenimports = [
"vivisect.impapi.posix.amd64",
"vivisect.impapi.posix.i386",
"vivisect.impapi.windows",
"vivisect.impapi.windows.advapi_32",
"vivisect.impapi.windows.advapi_64",
"vivisect.impapi.windows.amd64",
"vivisect.impapi.windows.gdi_32",
"vivisect.impapi.windows.gdi_64",
"vivisect.impapi.windows.i386",
"vivisect.impapi.windows.kernel_32",
"vivisect.impapi.windows.kernel_64",
"vivisect.impapi.windows.msvcr100_32",
"vivisect.impapi.windows.msvcr100_64",
"vivisect.impapi.windows.msvcr110_32",
"vivisect.impapi.windows.msvcr110_64",
"vivisect.impapi.windows.msvcr120_32",
"vivisect.impapi.windows.msvcr120_64",
"vivisect.impapi.windows.msvcr71_32",
"vivisect.impapi.windows.msvcr80_32",
"vivisect.impapi.windows.msvcr80_64",
"vivisect.impapi.windows.msvcr90_32",
"vivisect.impapi.windows.msvcr90_64",
"vivisect.impapi.windows.msvcrt_32",
"vivisect.impapi.windows.msvcrt_64",
"vivisect.impapi.windows.ntdll_32",
"vivisect.impapi.windows.ntdll_64",
"vivisect.impapi.windows.ole_32",
"vivisect.impapi.windows.ole_64",
"vivisect.impapi.windows.rpcrt4_32",
"vivisect.impapi.windows.rpcrt4_64",
"vivisect.impapi.windows.shell_32",
"vivisect.impapi.windows.shell_64",
"vivisect.impapi.windows.user_32",
"vivisect.impapi.windows.user_64",
"vivisect.impapi.windows.ws2plus_32",
"vivisect.impapi.windows.ws2plus_64",
"vivisect.impapi.winkern",
"vivisect.impapi.winkern.i386",
"vivisect.impapi.winkern.amd64",
"vivisect.parsers.blob",

View File

@@ -1,40 +1,55 @@
# -*- mode: python -*-
# Copyright (C) 2020 Mandiant, Inc. All Rights Reserved.
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
import os.path
import subprocess
import wcwidth
# when invoking pyinstaller from the project root,
# this gets run from the project root.
with open('./capa/version.py', 'wb') as f:
# git output will look like:
#
# tags/v1.0.0-0-g3af38dc
# ------- tag
# - commits since
# g------- git hash fragment
version = (subprocess.check_output(["git", "describe", "--always", "--tags", "--long"])
.decode("utf-8")
.strip()
.replace("tags/", ""))
f.write(("__version__ = '%s'" % version).encode("utf-8"))
a = Analysis(
# when invoking pyinstaller from the project root,
# this gets invoked from the directory of the spec file,
# i.e. ./.github/pyinstaller
["../../capa/main.py"],
pathex=["capa"],
['../../capa/main.py'],
pathex=['capa'],
binaries=None,
datas=[
# when invoking pyinstaller from the project root,
# this gets invoked from the directory of the spec file,
# i.e. ./.github/pyinstaller
("../../rules", "rules"),
("../../sigs", "sigs"),
("../../cache", "cache"),
('../../rules', 'rules'),
# capa.render.default uses tabulate that depends on wcwidth.
# it seems wcwidth uses a json file `version.json`
# and this doesn't get picked up by pyinstaller automatically.
# so we manually embed the wcwidth resources here.
#
# ref: https://stackoverflow.com/a/62278462/87207
(os.path.dirname(wcwidth.__file__), "wcwidth"),
(os.path.dirname(wcwidth.__file__), 'wcwidth')
],
# when invoking pyinstaller from the project root,
# this gets run from the project root.
hookspath=[".github/pyinstaller/hooks"],
hookspath=['.github/pyinstaller/hooks'],
runtime_hooks=None,
excludes=[
# ignore packages that would otherwise be bundled with the .exe.
# review: build/pyinstaller/xref-pyinstaller.html
# we don't do any GUI stuff, so ignore these modules
"tkinter",
"_tkinter",
@@ -44,6 +59,7 @@ a = Analysis(
# since we don't spawn a notebook, we can safely remove these.
"IPython",
"ipywidgets",
# these are pulled in by networkx
# but we don't need to compute the strongly connected components.
"numpy",
@@ -51,6 +67,7 @@ a = Analysis(
"matplotlib",
"pandas",
"pytest",
# deps from viv that we don't use.
# this duplicates the entries in `hook-vivisect`,
# but works better this way.
@@ -60,36 +77,36 @@ a = Analysis(
"PyQt5",
"qt5",
"pyqtwebengine",
"pyasn1",
"binaryninja",
],
)
"pyasn1"
])
a.binaries = a.binaries - TOC([("tcl85.dll", None, None), ("tk85.dll", None, None), ("_tkinter", None, None)])
a.binaries = a.binaries - TOC([
('tcl85.dll', None, None),
('tk85.dll', None, None),
('_tkinter', None, None)])
pyz = PYZ(a.pure, a.zipped_data)
exe = EXE(
pyz,
a.scripts,
a.binaries,
a.zipfiles,
a.datas,
exclude_binaries=False,
name="capa",
icon="logo.ico",
debug=False,
strip=None,
upx=True,
console=True,
)
exe = EXE(pyz,
a.scripts,
a.binaries,
a.zipfiles,
a.datas,
exclude_binaries=False,
name='capa',
icon='logo.ico',
debug=False,
strip=None,
upx=True,
console=True )
# enable the following to debug the contents of the .exe
#
# coll = COLLECT(exe,
#coll = COLLECT(exe,
# a.binaries,
# a.zipfiles,
# a.datas,
# strip=None,
# upx=True,
# name='capa-dat')

43
.github/ruff.toml vendored
View File

@@ -1,43 +0,0 @@
# Enable the pycodestyle (`E`) and Pyflakes (`F`) rules by default.
# Unlike Flake8, Ruff doesn't enable pycodestyle warnings (`W`) or
# McCabe complexity (`C901`) by default.
select = ["E", "F"]
# Allow autofix for all enabled rules (when `--fix`) is provided.
fixable = ["ALL"]
unfixable = []
# E402 module level import not at top of file
# E722 do not use bare 'except'
# E501 line too long
ignore = ["E402", "E722", "E501"]
line-length = 120
exclude = [
# Exclude a variety of commonly ignored directories.
".bzr",
".direnv",
".eggs",
".git",
".git-rewrite",
".hg",
".mypy_cache",
".nox",
".pants.d",
".pytype",
".ruff_cache",
".svn",
".tox",
".venv",
"__pypackages__",
"_build",
"buck-out",
"build",
"dist",
"node_modules",
"venv",
# protobuf generated files
"*_pb2.py",
"*_pb2.pyi"
]

10
.github/tox.ini vendored Normal file
View File

@@ -0,0 +1,10 @@
[pycodestyle]
; E402: module level import not at top of file
; W503: line break before binary operator
; E231 missing whitespace after ',' (emitted by black)
; E203 whitespace before ':' (emitted by black)
ignore = E402,W503,E203,E231
max-line-length = 160
statistics = True
count = True
exclude = .*

View File

@@ -1,96 +1,54 @@
name: build
on:
pull_request:
branches: [ master ]
release:
types: [edited, published]
permissions:
contents: write
jobs:
build:
name: PyInstaller for ${{ matrix.os }}
runs-on: ${{ matrix.os }}
strategy:
# set to false for debugging
fail-fast: true
matrix:
include:
- os: ubuntu-20.04
- os: ubuntu-16.04
# use old linux so that the shared library versioning is more portable
artifact_name: capa
asset_name: linux
- os: windows-2019
artifact_name: capa.exe
asset_name: windows
- os: macos-11
# use older macOS for assumed better portability
- os: macos-10.15
artifact_name: capa
asset_name: macos
steps:
- name: Checkout capa
uses: actions/checkout@ac593985615ec2ede58e132d2e21d2b1cbd6127c # v3.3.0
uses: actions/checkout@v2
with:
submodules: true
# using Python 3.8 to support running across multiple operating systems including Windows 7
- name: Set up Python 3.8
uses: actions/setup-python@d27e3f3d7c64b4bbf8e4abfb9b63b83e846e0435 # v4.5.0
uses: actions/setup-python@v2
with:
python-version: 3.8
- if: matrix.os == 'ubuntu-20.04'
- if: matrix.os == 'ubuntu-16.04'
run: sudo apt-get install -y libyaml-dev
- name: Upgrade pip, setuptools
run: python -m pip install --upgrade pip setuptools
- name: Install capa with build requirements
run: pip install -e .[build]
- name: Cache the rule set
run: python ./scripts/cache-ruleset.py ./rules/ ./cache/
- name: Install PyInstaller
run: pip install 'pyinstaller==4.2'
- name: Install capa
run: pip install -e .
- name: Build standalone executable
run: pyinstaller --log-level DEBUG .github/pyinstaller/pyinstaller.spec
- name: Does it run (PE)?
run: pyinstaller .github/pyinstaller/pyinstaller.spec
- name: Does it run?
run: dist/capa "tests/data/Practical Malware Analysis Lab 01-01.dll_"
- name: Does it run (Shellcode)?
run: dist/capa "tests/data/499c2a85f6e8142c3f48d4251c9c7cd6.raw32"
- name: Does it run (ELF)?
run: dist/capa "tests/data/7351f8a40c5450557b24622417fc478d.elf_"
- uses: actions/upload-artifact@0b7f8abb1508181956e8e162db84b466c27e18ce # v3.1.2
- uses: actions/upload-artifact@v2
with:
name: ${{ matrix.asset_name }}
path: dist/${{ matrix.artifact_name }}
test_run:
name: Test run on ${{ matrix.os }}
runs-on: ${{ matrix.os }}
needs: [build]
strategy:
matrix:
include:
# OSs not already tested above
- os: ubuntu-22.04
artifact_name: capa
asset_name: linux
- os: windows-2022
artifact_name: capa.exe
asset_name: windows
steps:
- name: Download ${{ matrix.asset_name }}
uses: actions/download-artifact@9bc31d5ccc31df68ecc42ccf4149144866c47d8a # v3.0.2
with:
name: ${{ matrix.asset_name }}
- name: Set executable flag
if: matrix.os != 'windows-2022'
run: chmod +x ${{ matrix.artifact_name }}
- name: Run capa
run: ./${{ matrix.artifact_name }} -h
zip_and_upload:
# upload zipped binaries to Release page
if: github.event_name == 'release'
name: zip and upload ${{ matrix.asset_name }}
zip:
name: zip ${{ matrix.asset_name }}
runs-on: ubuntu-20.04
needs: [build]
needs: build
strategy:
matrix:
include:
@@ -102,7 +60,7 @@ jobs:
artifact_name: capa
steps:
- name: Download ${{ matrix.asset_name }}
uses: actions/download-artifact@9bc31d5ccc31df68ecc42ccf4149144866c47d8a # v3.0.2
uses: actions/download-artifact@v2
with:
name: ${{ matrix.asset_name }}
- name: Set executable flag
@@ -112,7 +70,7 @@ jobs:
- name: Zip ${{ matrix.artifact_name }} into ${{ env.zip_name }}
run: zip ${{ env.zip_name }} ${{ matrix.artifact_name }}
- name: Upload ${{ env.zip_name }} to GH Release
uses: svenstaro/upload-release-action@2728235f7dc9ff598bd86ce3c274b74f802d2208 # v2
uses: svenstaro/upload-release-action@v2
with:
repo_token: ${{ secrets.GITHUB_TOKEN}}
file: ${{ env.zip_name }}

View File

@@ -1,43 +0,0 @@
name: changelog
on:
# We need pull_request_target instead of pull_request because a write
# repository token is needed to add a review to a PR. DO NOT BUILD
# OR RUN UNTRUSTED CODE FROM PRs IN THIS ACTION
pull_request_target:
types: [opened, edited, synchronize]
permissions: read-all
jobs:
check_changelog:
# no need to check for dependency updates via dependabot
if: github.actor != 'dependabot[bot]' && github.actor != 'dependabot-preview[bot]'
runs-on: ubuntu-20.04
env:
NO_CHANGELOG: '[x] No CHANGELOG update needed'
steps:
- name: Get changed files
id: files
uses: Ana06/get-changed-files@e0c398b7065a8d84700c471b6afc4116d1ba4e96 # v2.2.0
- name: check changelog updated
id: changelog_updated
env:
PR_BODY: ${{ github.event.pull_request.body }}
FILES: ${{ steps.files.outputs.modified }}
run: |
echo $FILES | grep -qF 'CHANGELOG.md' || echo $PR_BODY | grep -qiF "$NO_CHANGELOG"
- name: Reject pull request if no CHANGELOG update
if: ${{ always() && steps.changelog_updated.outcome == 'failure' }}
uses: Ana06/automatic-pull-request-review@0cf4e8a17ba79344ed3fdd7fed6dd0311d08a9d4 # v0.1.0
with:
repo-token: ${{ secrets.GITHUB_TOKEN }}
event: REQUEST_CHANGES
body: "Please add bug fixes, new features, breaking changes and anything else you think is worthwhile mentioning to the `master (unreleased)` section of CHANGELOG.md. If no CHANGELOG update is needed add the following to the PR description: `${{ env.NO_CHANGELOG }}`"
allow_duplicate: false
- name: Dismiss previous review if CHANGELOG update
uses: Ana06/automatic-pull-request-review@0cf4e8a17ba79344ed3fdd7fed6dd0311d08a9d4 # v0.1.0
with:
repo-token: ${{ secrets.GITHUB_TOKEN }}
event: DISMISS
body: "CHANGELOG updated or no update needed, thanks! :smile:"

View File

@@ -1,41 +1,29 @@
# use PyPI trusted publishing, as described here:
# https://blog.trailofbits.com/2023/05/23/trusted-publishing-a-new-benchmark-for-packaging-security/
# This workflows will upload a Python Package using Twine when a release is created
# For more information see: https://help.github.com/en/actions/language-and-framework-guides/using-python-with-github-actions#publishing-to-package-registries
name: publish to pypi
on:
release:
types: [published]
permissions:
contents: write
jobs:
pypi-publish:
runs-on: ubuntu-latest
environment:
name: release
permissions:
id-token: write
deploy:
runs-on: ubuntu-20.04
steps:
- uses: actions/checkout@ac593985615ec2ede58e132d2e21d2b1cbd6127c # v3.3.0
- uses: actions/checkout@v2
- name: Set up Python
uses: actions/setup-python@d27e3f3d7c64b4bbf8e4abfb9b63b83e846e0435 # v4.5.0
uses: actions/setup-python@v2
with:
python-version: '3.8'
python-version: '2.7'
- name: Install dependencies
run: |
python -m pip install --upgrade pip
pip install -e .[build]
- name: build package
pip install setuptools wheel twine
- name: Build and publish
env:
TWINE_USERNAME: ${{ secrets.PYPI_USERNAME }}
TWINE_PASSWORD: ${{ secrets.PYPI_PASSWORD }}
run: |
python -m build
- name: upload package artifacts
uses: actions/upload-artifact@0b7f8abb1508181956e8e162db84b466c27e18ce # v3.1.2
with:
path: dist/*
- name: publish package
uses: pypa/gh-action-pypi-publish@f5622bde02b04381239da3573277701ceca8f6a0 # release/v1
with:
skip-existing: true
verbose: true
print-hash: true
python setup.py sdist bdist_wheel
twine upload --skip-existing dist/*

View File

@@ -1,72 +0,0 @@
# This workflow uses actions that are not certified by GitHub. They are provided
# by a third-party and are governed by separate terms of service, privacy
# policy, and support documentation.
name: Scorecard supply-chain security
on:
# For Branch-Protection check. Only the default branch is supported. See
# https://github.com/ossf/scorecard/blob/main/docs/checks.md#branch-protection
branch_protection_rule:
# To guarantee Maintained check is occasionally updated. See
# https://github.com/ossf/scorecard/blob/main/docs/checks.md#maintained
schedule:
- cron: '43 4 * * 3'
push:
branches: [ "master" ]
# Declare default permissions as read only.
permissions: read-all
jobs:
analysis:
name: Scorecard analysis
runs-on: ubuntu-latest
permissions:
# Needed to upload the results to code-scanning dashboard.
security-events: write
# Needed to publish results and get a badge (see publish_results below).
id-token: write
# Uncomment the permissions below if installing in a private repository.
# contents: read
# actions: read
steps:
- name: "Checkout code"
uses: actions/checkout@93ea575cb5d8a053eaa0ac8fa3b40d7e05a33cc8 # v3.1.0
with:
persist-credentials: false
- name: "Run analysis"
uses: ossf/scorecard-action@99c53751e09b9529366343771cc321ec74e9bd3d # v2.0.6
with:
results_file: results.sarif
results_format: sarif
# (Optional) "write" PAT token. Uncomment the `repo_token` line below if:
# - you want to enable the Branch-Protection check on a *public* repository, or
# - you are installing Scorecard on a *private* repository
# To create the PAT, follow the steps in https://github.com/ossf/scorecard-action#authentication-with-pat.
# repo_token: ${{ secrets.SCORECARD_TOKEN }}
# Public repositories:
# - Publish results to OpenSSF REST API for easy access by consumers
# - Allows the repository to include the Scorecard badge.
# - See https://github.com/ossf/scorecard-action#publishing-results.
# For private repositories:
# - `publish_results` will always be set to `false`, regardless
# of the value entered here.
publish_results: true
# Upload the results as artifacts (optional). Commenting out will disable uploads of run results in SARIF
# format to the repository Actions tab.
- name: "Upload artifact"
uses: actions/upload-artifact@3cea5372237819ed00197afe530f5a7ea3e805c8 # v3.1.0
with:
name: SARIF file
path: results.sarif
retention-days: 5
# Upload the results to GitHub's code scanning dashboard.
- name: "Upload to code-scanning"
uses: github/codeql-action/upload-sarif@807578363a7869ca324a79039e6db9c843e0e100 # v2.1.27
with:
sarif_file: results.sarif

View File

@@ -4,29 +4,21 @@ on:
release:
types: [published]
permissions: read-all
jobs:
tag:
name: Tag capa rules
runs-on: ubuntu-20.04
steps:
- name: Checkout capa-rules
uses: actions/checkout@ac593985615ec2ede58e132d2e21d2b1cbd6127c # v3.3.0
uses: actions/checkout@v2
with:
repository: mandiant/capa-rules
repository: fireeye/capa-rules
token: ${{ secrets.CAPA_TOKEN }}
- name: Tag capa-rules
run: |
# user information is needed to create annotated tags (with a message)
git config user.email 'capa-dev@mandiant.com'
git config user.name 'Capa Bot'
name=${{ github.event.release.tag_name }}
git tag $name -m "https://github.com/mandiant/capa/releases/$name"
# TODO update branch name-major=${name%%.*}
run: git tag ${{ github.event.release.tag_name }}
- name: Push tag to capa-rules
uses: ad-m/github-push-action@0fafdd62b84042d49ec0cb92d9cac7f7ce4ec79e # master
uses: ad-m/github-push-action@master
with:
repository: mandiant/capa-rules
repository: fireeye/capa-rules
github_token: ${{ secrets.CAPA_TOKEN }}
tags: true

View File

@@ -2,64 +2,40 @@ name: CI
on:
push:
branches: [ master ]
branches: [ master, master-py2 ]
pull_request:
branches: [ master ]
permissions: read-all
# save workspaces to speed up testing
env:
CAPA_SAVE_WORKSPACE: "True"
branches: [ master, master-py2 ]
jobs:
changelog_format:
runs-on: ubuntu-20.04
steps:
- name: Checkout capa
uses: actions/checkout@ac593985615ec2ede58e132d2e21d2b1cbd6127c # v3.3.0
# The sync GH action in capa-rules relies on a single '- *$' in the CHANGELOG file
- name: Ensure CHANGELOG has '- *$'
run: |
number=$(grep '\- *$' CHANGELOG.md | wc -l)
if [ $number != 1 ]; then exit 1; fi
code_style:
runs-on: ubuntu-20.04
steps:
- name: Checkout capa
uses: actions/checkout@ac593985615ec2ede58e132d2e21d2b1cbd6127c # v3.3.0
# use latest available python to take advantage of best performance
- name: Set up Python 3.11
uses: actions/setup-python@d27e3f3d7c64b4bbf8e4abfb9b63b83e846e0435 # v4.5.0
uses: actions/checkout@v2
- name: Set up Python 3.8
uses: actions/setup-python@v2
with:
python-version: "3.11"
python-version: 3.8
- name: Install dependencies
run: pip install -e .[dev]
- name: Lint with ruff
run: pre-commit run ruff
- name: Lint with isort
run: pre-commit run isort
run: isort --profile black --length-sort --line-width 120 -c .
- name: Lint with black
run: pre-commit run black
- name: Lint with flake8
run: pre-commit run flake8
- name: Check types with mypy
run: pre-commit run mypy
run: black -l 120 --check .
rule_linter:
runs-on: ubuntu-20.04
steps:
- name: Checkout capa with submodules
uses: actions/checkout@ac593985615ec2ede58e132d2e21d2b1cbd6127c # v3.3.0
- name: Checkout capa with rules submodule
uses: actions/checkout@v2
with:
submodules: recursive
- name: Set up Python 3.11
uses: actions/setup-python@d27e3f3d7c64b4bbf8e4abfb9b63b83e846e0435 # v4.5.0
submodules: true
- name: Set up Python 3.8
uses: actions/setup-python@v2
with:
python-version: "3.11"
python-version: 3.8
- name: Install capa
run: pip install -e .[dev]
run: pip install -e .
- name: Run rule linter
run: python scripts/lint.py rules/
@@ -70,131 +46,33 @@ jobs:
strategy:
fail-fast: false
matrix:
os: [ubuntu-20.04, windows-2019, macos-11]
os: [ubuntu-20.04, windows-2019, macos-10.15]
# across all operating systems
python-version: ["3.8", "3.11"]
python-version: [3.6, 3.9]
include:
# on Ubuntu run these as well
- os: ubuntu-20.04
python-version: "3.8"
python-version: 2.7
- os: ubuntu-20.04
python-version: "3.9"
python-version: 3.7
- os: ubuntu-20.04
python-version: "3.10"
python-version: 3.8
steps:
- name: Checkout capa with submodules
uses: actions/checkout@ac593985615ec2ede58e132d2e21d2b1cbd6127c # v3.3.0
uses: actions/checkout@v2
with:
submodules: recursive
submodules: true
- name: Set up Python ${{ matrix.python-version }}
uses: actions/setup-python@d27e3f3d7c64b4bbf8e4abfb9b63b83e846e0435 # v4.5.0
uses: actions/setup-python@v2
with:
python-version: ${{ matrix.python-version }}
- name: Install pyyaml
if: matrix.os == 'ubuntu-20.04'
run: sudo apt-get install -y libyaml-dev
- name: Install Microsoft Visual C++ 9.0
if: matrix.os == 'windows-2019' && matrix.python-version == '2.7'
run: choco install vcpython27
- name: Install capa
run: pip install -e .[dev]
- name: Run tests
run: pytest -v tests/
binja-tests:
name: Binary Ninja tests for ${{ matrix.python-version }}
env:
BN_SERIAL: ${{ secrets.BN_SERIAL }}
runs-on: ubuntu-20.04
needs: [code_style, rule_linter]
strategy:
fail-fast: false
matrix:
python-version: ["3.8", "3.11"]
steps:
- name: Checkout capa with submodules
# do only run if BN_SERIAL is available, have to do this in every step, see https://github.com/orgs/community/discussions/26726#discussioncomment-3253118
if: ${{ env.BN_SERIAL != 0 }}
uses: actions/checkout@ac593985615ec2ede58e132d2e21d2b1cbd6127c # v3.3.0
with:
submodules: recursive
- name: Set up Python ${{ matrix.python-version }}
if: ${{ env.BN_SERIAL != 0 }}
uses: actions/setup-python@d27e3f3d7c64b4bbf8e4abfb9b63b83e846e0435 # v4.5.0
with:
python-version: ${{ matrix.python-version }}
- name: Install pyyaml
if: ${{ env.BN_SERIAL != 0 }}
run: sudo apt-get install -y libyaml-dev
- name: Install capa
if: ${{ env.BN_SERIAL != 0 }}
run: pip install -e .[dev]
- name: install Binary Ninja
if: ${{ env.BN_SERIAL != 0 }}
run: |
mkdir ./.github/binja
curl "https://raw.githubusercontent.com/Vector35/binaryninja-api/6812c97/scripts/download_headless.py" -o ./.github/binja/download_headless.py
python ./.github/binja/download_headless.py --serial ${{ env.BN_SERIAL }} --output .github/binja/BinaryNinja-headless.zip
unzip .github/binja/BinaryNinja-headless.zip -d .github/binja/
python .github/binja/binaryninja/scripts/install_api.py --install-on-root --silent
- name: Run tests
if: ${{ env.BN_SERIAL != 0 }}
env:
BN_LICENSE: ${{ secrets.BN_LICENSE }}
run: pytest -v tests/test_binja_features.py # explicitly refer to the binja tests for performance. other tests run above.
ghidra-tests:
name: Ghidra tests for ${{ matrix.python-version }}
runs-on: ubuntu-20.04
needs: [code_style, rule_linter]
strategy:
fail-fast: false
matrix:
python-version: ["3.8", "3.11"]
java-version: ["17"]
gradle-version: ["7.3"]
ghidra-version: ["10.3"]
public-version: ["PUBLIC_20230510"] # for ghidra releases
jep-version: ["4.1.1"]
ghidrathon-version: ["3.0.0"]
steps:
- name: Checkout capa with submodules
uses: actions/checkout@ac593985615ec2ede58e132d2e21d2b1cbd6127c # v3.3.0
with:
submodules: true
- name: Set up Python ${{ matrix.python-version }}
uses: actions/setup-python@d27e3f3d7c64b4bbf8e4abfb9b63b83e846e0435 # v4.5.0
with:
python-version: ${{ matrix.python-version }}
- name: Set up Java ${{ matrix.java-version }}
uses: actions/setup-java@5ffc13f4174014e2d4d4572b3d74c3fa61aeb2c2 # v3
with:
distribution: 'temurin'
java-version: ${{ matrix.java-version }}
- name: Set up Gradle ${{ matrix.gradle-version }}
uses: gradle/gradle-build-action@40b6781dcdec2762ad36556682ac74e31030cfe2 # v2.5.1
with:
gradle-version: ${{ matrix.gradle-version }}
- name: Install Jep ${{ matrix.jep-version }}
run : pip install jep==${{ matrix.jep-version }}
- name: Install Ghidra ${{ matrix.ghidra-version }}
run: |
mkdir ./.github/ghidra
wget "https://github.com/NationalSecurityAgency/ghidra/releases/download/Ghidra_${{ matrix.ghidra-version }}_build/ghidra_${{ matrix.ghidra-version }}_${{ matrix.public-version }}.zip" -O ./.github/ghidra/ghidra_${{ matrix.ghidra-version }}_PUBLIC.zip
unzip .github/ghidra/ghidra_${{ matrix.ghidra-version }}_PUBLIC.zip -d .github/ghidra/
- name: Install Ghidrathon
run : |
mkdir ./.github/ghidrathon
curl -o ./.github/ghidrathon/ghidrathon-${{ matrix.ghidrathon-version }}.zip "https://codeload.github.com/mandiant/Ghidrathon/zip/refs/tags/v${{ matrix.ghidrathon-version }}"
unzip .github/ghidrathon/ghidrathon-${{ matrix.ghidrathon-version }}.zip -d .github/ghidrathon/
gradle -p ./.github/ghidrathon/Ghidrathon-${{ matrix.ghidrathon-version }}/ -PGHIDRA_INSTALL_DIR=$(pwd)/.github/ghidra/ghidra_${{ matrix.ghidra-version }}_PUBLIC
unzip .github/ghidrathon/Ghidrathon-${{ matrix.ghidrathon-version }}/dist/*.zip -d .github/ghidra/ghidra_${{ matrix.ghidra-version }}_PUBLIC/Ghidra/Extensions
- name: Install pyyaml
run: sudo apt-get install -y libyaml-dev
- name: Install capa
run: pip install -e .[dev]
- name: Run tests
run: |
mkdir ./.github/ghidra/project
.github/ghidra/ghidra_${{ matrix.ghidra-version }}_PUBLIC/support/analyzeHeadless .github/ghidra/project ghidra_test -Import ./tests/data/mimikatz.exe_ -ScriptPath ./tests/ -PostScript test_ghidra_features.py > ../output.log
cat ../output.log
exit_code=$(cat ../output.log | grep exit | awk '{print $NF}')
exit $exit_code
run: pytest tests/

20
.gitignore vendored
View File

@@ -108,21 +108,9 @@ venv.bak/
*.viv
*.idb
*.i64
.vscode
!rules/lib
scripts/perf/*.txt
scripts/perf/*.svg
scripts/perf/*.zip
.direnv
.envrc
.DS_Store
*/.DS_Store
Pipfile
Pipfile.lock
/cache/
.github/binja/binaryninja
.github/binja/download_headless.py
.github/binja/BinaryNinja-headless.zip
# hooks/ci.sh output
isort-output.log
black-output.log
rule-linter-output.log

View File

@@ -1,111 +0,0 @@
# install the pre-commit hooks:
#
# pre-commit install --hook-type pre-commit
# pre-commit installed at .git/hooks/pre-commit
#
# pre-commit install --hook-type pre-push
# pre-commit installed at .git/hooks/pre-push
#
# run all linters liks:
#
# pre-commit run --all-files
# isort....................................................................Passed
# black....................................................................Passed
# ruff.....................................................................Passed
# flake8...................................................................Passed
# mypy.....................................................................Passed
#
# run a single linter like:
#
# pre-commit run --all-files isort
# isort....................................................................Passed
repos:
- repo: local
hooks:
- id: isort
name: isort
stages: [commit, push]
language: system
entry: isort
args:
- "--length-sort"
- "--profile"
- "black"
- "--line-length=120"
- "--skip-glob"
- "*_pb2.py"
- "capa/"
- "scripts/"
- "tests/"
always_run: true
pass_filenames: false
- repo: local
hooks:
- id: black
name: black
stages: [commit, push]
language: system
entry: black
args:
- "--line-length=120"
- "--extend-exclude"
- ".*_pb2.py"
- "capa/"
- "scripts/"
- "tests/"
always_run: true
pass_filenames: false
- repo: local
hooks:
- id: ruff
name: ruff
stages: [commit, push]
language: system
entry: ruff
args:
- "check"
- "--config"
- ".github/ruff.toml"
- "capa/"
- "scripts/"
- "tests/"
always_run: true
pass_filenames: false
- repo: local
hooks:
- id: flake8
name: flake8
stages: [commit, push]
language: system
entry: flake8
args:
- "--config"
- ".github/flake8.ini"
- "--extend-exclude"
- "capa/render/proto/capa_pb2.py"
- "capa/"
- "scripts/"
- "tests/"
always_run: true
pass_filenames: false
- repo: local
hooks:
- id: mypy
name: mypy
stages: [commit, push]
language: system
entry: mypy
args:
- "--check-untyped-defs"
- "--ignore-missing-imports"
- "--config-file=.github/mypy/mypy.ini"
- "capa/"
- "scripts/"
- "tests/"
always_run: true
pass_filenames: false

File diff suppressed because it is too large Load Diff

View File

@@ -187,7 +187,7 @@
same "printed page" as the copyright notice for easier
identification within third-party archives.
Copyright (C) 2023 Mandiant, Inc.
Copyright (C) 2020 FireEye, Inc.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.

105
README.md
View File

@@ -1,21 +1,17 @@
![capa](https://github.com/mandiant/capa/blob/master/.github/logo.png)
![capa](.github/logo.png)
[![PyPI - Python Version](https://img.shields.io/pypi/pyversions/flare-capa)](https://pypi.org/project/flare-capa)
[![Last release](https://img.shields.io/github/v/release/mandiant/capa)](https://github.com/mandiant/capa/releases)
[![Number of rules](https://img.shields.io/badge/rules-832-blue.svg)](https://github.com/mandiant/capa-rules)
[![CI status](https://github.com/mandiant/capa/workflows/CI/badge.svg)](https://github.com/mandiant/capa/actions?query=workflow%3ACI+event%3Apush+branch%3Amaster)
[![Downloads](https://img.shields.io/github/downloads/mandiant/capa/total)](https://github.com/mandiant/capa/releases)
[![Last release](https://img.shields.io/github/v/release/fireeye/capa)](https://github.com/fireeye/capa/releases)
[![Number of rules](https://img.shields.io/badge/rules-485-blue.svg)](https://github.com/fireeye/capa-rules)
[![CI status](https://github.com/fireeye/capa/workflows/CI/badge.svg)](https://github.com/fireeye/capa/actions?query=workflow%3ACI+event%3Apush+branch%3Amaster)
[![Downloads](https://img.shields.io/github/downloads/fireeye/capa/total)](https://github.com/fireeye/capa/releases)
[![License](https://img.shields.io/badge/license-Apache--2.0-green.svg)](LICENSE.txt)
capa detects capabilities in executable files.
You run it against a PE, ELF, .NET module, or shellcode file and it tells you what it thinks the program can do.
You run it against a PE file or shellcode and it tells you what it thinks the program can do.
For example, it might suggest that the file is a backdoor, is capable of installing services, or relies on HTTP to communicate.
Check out:
- the overview in our first [capa blog post](https://www.mandiant.com/resources/capa-automatically-identify-malware-capabilities)
- the major version 2.0 updates described in our [second blog post](https://www.mandiant.com/resources/capa-2-better-stronger-faster)
- the major version 3.0 (ELF support) described in the [third blog post](https://www.mandiant.com/resources/elfant-in-the-room-capa-v3)
- the major version 4.0 (.NET support) described in the [fourth blog post](https://www.mandiant.com/resources/blog/capa-v4-casting-wider-net)
Check out the overview in our first [capa blog post](https://www.fireeye.com/blog/threat-research/2020/07/capa-automatically-identify-malware-capabilities.html).
```
$ capa.exe suspicious.exe
@@ -67,11 +63,18 @@ $ capa.exe suspicious.exe
# download and usage
Download stable releases of the standalone capa binaries [here](https://github.com/mandiant/capa/releases). You can run the standalone binaries without installation. capa is a command line tool that should be run from the terminal.
Download stable releases of the standalone capa binaries [here](https://github.com/fireeye/capa/releases). You can run the standalone binaries without installation. capa is a command line tool that should be run from the terminal.
To use capa as a library or integrate with another tool, see [doc/installation.md](https://github.com/mandiant/capa/blob/master/doc/installation.md) for further setup instructions.
<!--
Alternatively, you can fetch a nightly build of a standalone binary from one of the following links. These are built using the latest development branch.
- Windows 64bit: TODO
- Linux: TODO
- OSX: TODO
-->
For more information about how to use capa, see [doc/usage.md](https://github.com/mandiant/capa/blob/master/doc/usage.md).
To use capa as a library or integrate with another tool, see [doc/installation.md](doc/installation.md) for further setup instructions.
For more information about how to use capa, see [doc/usage.md](doc/usage.md).
# example
@@ -88,40 +91,31 @@ This is useful for at least two reasons:
- it shows where within the binary an experienced analyst might study with IDA Pro
```
$ capa.exe suspicious.exe -vv
λ capa.exe suspicious.exe -vv
...
execute shell command and capture output
namespace c2/shell
author matthew.williams@mandiant.com
author matthew.williams@fireeye.com
scope function
att&ck Execution::Command and Scripting Interpreter::Windows Command Shell [T1059.003]
references https://docs.microsoft.com/en-us/windows/win32/api/processthreadsapi/ns-processthreadsapi-startupinfoa
function @ 0x4011C0
examples Practical Malware Analysis Lab 14-02.exe_:0x4011C0
function @ 0x10003A13
and:
match: create a process with modified I/O handles and window @ 0x4011C0
match: create a process with modified I/O handles and window @ 0x10003A13
and:
number: 257 = STARTF_USESTDHANDLES | STARTF_USESHOWWINDOW @ 0x4012B8
or:
number: 68 = StartupInfo.cb (size) @ 0x401282
or: = API functions that accept a pointer to a STARTUPINFO structure
api: kernel32.CreateProcess @ 0x401343
match: create pipe @ 0x4011C0
api: kernel32.CreateProcess @ 0x10003D6D
number: 0x101 @ 0x10003B03
or:
number: 0x44 @ 0x10003ADC
optional:
api: kernel32.GetStartupInfo @ 0x10003AE4
match: create pipe @ 0x10003A13
or:
api: kernel32.CreatePipe @ 0x40126F, 0x401280
optional:
match: create thread @ 0x40136A, 0x4013BA
or:
and:
os: windows
or:
api: kernel32.CreateThread @ 0x4013D7
or:
and:
os: windows
or:
api: kernel32.CreateThread @ 0x401395
api: kernel32.CreatePipe @ 0x10003ACB
or:
string: "cmd.exe" @ 0x4012FD
string: cmd.exe /c @ 0x10003AED
...
```
@@ -137,51 +131,36 @@ rule:
meta:
name: hash data with CRC32
namespace: data-manipulation/checksum/crc32
authors:
- moritz.raabe@mandiant.com
author: moritz.raabe@fireeye.com
scope: function
mbc:
- Data::Checksum::CRC32 [C0032.001]
examples:
- 2D3EDC218A90F03089CC01715A9F047F:0x403CBD
- 7D28CB106CB54876B2A5C111724A07CD:0x402350 # RtlComputeCrc32
- 7EFF498DE13CC734262F87E6B3EF38AB:0x100084A6
features:
- or:
- and:
- mnemonic: shr
- or:
- number: 0xEDB88320
- bytes: 00 00 00 00 96 30 07 77 2C 61 0E EE BA 51 09 99 19 C4 6D 07 8F F4 6A 70 35 A5 63 E9 A3 95 64 9E = crc32_tab
- number: 0xEDB88320
- number: 8
- characteristic: nzxor
- and:
- number: 0x8320
- number: 0xEDB8
- characteristic: nzxor
- api: RtlComputeCrc32
```
The [github.com/mandiant/capa-rules](https://github.com/mandiant/capa-rules) repository contains hundreds of standard library rules that are distributed with capa.
The [github.com/fireeye/capa-rules](https://github.com/fireeye/capa-rules) repository contains hundreds of standard library rules that are distributed with capa.
Please learn to write rules and contribute new entries as you find interesting techniques in malware.
If you use IDA Pro, then you can use the [capa explorer](https://github.com/mandiant/capa/tree/master/capa/ida/plugin) plugin.
If you use IDA Pro, then you can use the [capa explorer](capa/ida/plugin/) plugin.
capa explorer helps you identify interesting areas of a program and build new capa rules using features extracted directly from your IDA Pro database.
![capa + IDA Pro integration](https://github.com/mandiant/capa/blob/master/doc/img/explorer_expanded.png)
If you use Ghidra, you can use the Python 3 [Ghidra feature extractor](/capa/ghidra/). This integration enables capa to extract features directly from your Ghidra database, which can help you identify capabilities in programs that you analyze using Ghidra.
![capa + IDA Pro integration](doc/img/explorer_expanded.png)
# further information
## capa
- [Installation](https://github.com/mandiant/capa/blob/master/doc/installation.md)
- [Usage](https://github.com/mandiant/capa/blob/master/doc/usage.md)
- [Limitations](https://github.com/mandiant/capa/blob/master/doc/limitations.md)
- [Contributing Guide](https://github.com/mandiant/capa/blob/master/.github/CONTRIBUTING.md)
- [doc/installation](doc/installation.md)
- [doc/usage](doc/usage.md)
- [doc/limitations](doc/limitations.md)
- [Contributing Guide](.github/CONTRIBUTING.md)
## capa rules
- [capa-rules repository](https://github.com/mandiant/capa-rules)
- [capa-rules rule format](https://github.com/mandiant/capa-rules/blob/master/doc/format.md)
## capa testfiles
The [capa-testfiles repository](https://github.com/mandiant/capa-testfiles) contains the data we use to test capa's code and rules
- [capa-rules repository](https://github.com/fireeye/capa-rules)
- [capa-rules rule format](https://github.com/fireeye/capa-rules/blob/master/doc/format.md)

View File

@@ -1,4 +1,4 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
@@ -8,29 +8,11 @@
import copy
import collections
from typing import TYPE_CHECKING, Set, Dict, List, Tuple, Union, Mapping, Iterable, Iterator
import capa.perf
import capa.features.common
from capa.features.common import Result, Feature
from capa.features.address import Address
if TYPE_CHECKING:
# circular import, otherwise
import capa.rules
import capa.features
# a collection of features and the locations at which they are found.
#
# used throughout matching as the context in which features are searched:
# to check if a feature exists, do: `Number(0x10) in features`.
# to collect the locations of a feature, do: `features[Number(0x10)]`
#
# aliased here so that the type can be documented and xref'd.
FeatureSet = Dict[Feature, Set[Address]]
class Statement:
class Statement(object):
"""
superclass for structural nodes, such as and/or/not.
this exists to provide a default impl for `__str__` and `__repr__`,
@@ -38,194 +20,157 @@ class Statement:
"""
def __init__(self, description=None):
super().__init__()
super(Statement, self).__init__()
self.name = self.__class__.__name__
self.description = description
def __str__(self):
name = self.name.lower()
children = ",".join(map(str, self.get_children()))
if self.description:
return f"{name}({children} = {self.description})"
return "%s(%s = %s)" % (self.name.lower(), ",".join(map(str, self.get_children())), self.description)
else:
return f"{name}({children})"
return "%s(%s)" % (self.name.lower(), ",".join(map(str, self.get_children())))
def __repr__(self):
return str(self)
def evaluate(self, features: FeatureSet, short_circuit=True) -> Result:
def evaluate(self, ctx):
"""
classes that inherit `Statement` must implement `evaluate`
args:
short_circuit (bool): if true, then statements like and/or/some may short circuit.
ctx (defaultdict[Feature, set[VA]])
returns:
Result
"""
raise NotImplementedError()
def get_children(self) -> Iterator[Union["Statement", Feature]]:
def get_children(self):
if hasattr(self, "child"):
# this really confuses mypy because the property may not exist
# since its defined in the subclasses.
child = self.child # type: ignore
assert isinstance(child, (Statement, Feature))
yield child
yield self.child
if hasattr(self, "children"):
for child in self.children:
assert isinstance(child, (Statement, Feature))
yield child
def replace_child(self, existing, new):
if hasattr(self, "child"):
# this really confuses mypy because the property may not exist
# since its defined in the subclasses.
if self.child is existing: # type: ignore
if self.child is existing:
self.child = new
if hasattr(self, "children"):
children = self.children
for i, child in enumerate(children):
for i, child in enumerate(self.children):
if child is existing:
children[i] = new
self.children[i] = new
class Result(object):
"""
represents the results of an evaluation of statements against features.
instances of this class should behave like a bool,
e.g. `assert Result(True, ...) == True`
instances track additional metadata about evaluation results.
they contain references to the statement node (e.g. an And statement),
as well as the children Result instances.
we need this so that we can render the tree of expressions and their results.
"""
def __init__(self, success, statement, children, locations=None):
"""
args:
success (bool)
statement (capa.engine.Statement or capa.features.Feature)
children (list[Result])
locations (iterable[VA])
"""
super(Result, self).__init__()
self.success = success
self.statement = statement
self.children = children
self.locations = locations if locations is not None else ()
def __eq__(self, other):
if isinstance(other, bool):
return self.success == other
return False
def __bool__(self):
return self.success
def __nonzero__(self):
return self.success
class And(Statement):
"""
match if all of the children evaluate to True.
the order of evaluation is dictated by the property
`And.children` (type: List[Statement|Feature]).
a query optimizer may safely manipulate the order of these children.
"""
"""match if all of the children evaluate to True."""
def __init__(self, children, description=None):
super().__init__(description=description)
super(And, self).__init__(description=description)
self.children = children
def evaluate(self, ctx, short_circuit=True):
capa.perf.counters["evaluate.feature"] += 1
capa.perf.counters["evaluate.feature.and"] += 1
if short_circuit:
results = []
for child in self.children:
result = child.evaluate(ctx, short_circuit=short_circuit)
results.append(result)
if not result:
# short circuit
return Result(False, self, results)
return Result(True, self, results)
else:
results = [child.evaluate(ctx, short_circuit=short_circuit) for child in self.children]
success = all(results)
return Result(success, self, results)
def evaluate(self, ctx):
results = [child.evaluate(ctx) for child in self.children]
success = all(results)
return Result(success, self, results)
class Or(Statement):
"""
match if any of the children evaluate to True.
the order of evaluation is dictated by the property
`Or.children` (type: List[Statement|Feature]).
a query optimizer may safely manipulate the order of these children.
"""
"""match if any of the children evaluate to True."""
def __init__(self, children, description=None):
super().__init__(description=description)
super(Or, self).__init__(description=description)
self.children = children
def evaluate(self, ctx, short_circuit=True):
capa.perf.counters["evaluate.feature"] += 1
capa.perf.counters["evaluate.feature.or"] += 1
if short_circuit:
results = []
for child in self.children:
result = child.evaluate(ctx, short_circuit=short_circuit)
results.append(result)
if result:
# short circuit as soon as we hit one match
return Result(True, self, results)
return Result(False, self, results)
else:
results = [child.evaluate(ctx, short_circuit=short_circuit) for child in self.children]
success = any(results)
return Result(success, self, results)
def evaluate(self, ctx):
results = [child.evaluate(ctx) for child in self.children]
success = any(results)
return Result(success, self, results)
class Not(Statement):
"""match only if the child evaluates to False."""
def __init__(self, child, description=None):
super().__init__(description=description)
super(Not, self).__init__(description=description)
self.child = child
def evaluate(self, ctx, short_circuit=True):
capa.perf.counters["evaluate.feature"] += 1
capa.perf.counters["evaluate.feature.not"] += 1
results = [self.child.evaluate(ctx, short_circuit=short_circuit)]
def evaluate(self, ctx):
results = [self.child.evaluate(ctx)]
success = not results[0]
return Result(success, self, results)
class Some(Statement):
"""
match if at least N of the children evaluate to True.
the order of evaluation is dictated by the property
`Some.children` (type: List[Statement|Feature]).
a query optimizer may safely manipulate the order of these children.
"""
"""match if at least N of the children evaluate to True."""
def __init__(self, count, children, description=None):
super().__init__(description=description)
super(Some, self).__init__(description=description)
self.count = count
self.children = children
def evaluate(self, ctx, short_circuit=True):
capa.perf.counters["evaluate.feature"] += 1
capa.perf.counters["evaluate.feature.some"] += 1
if short_circuit:
results = []
satisfied_children_count = 0
for child in self.children:
result = child.evaluate(ctx, short_circuit=short_circuit)
results.append(result)
if result:
satisfied_children_count += 1
if satisfied_children_count >= self.count:
# short circuit as soon as we hit the threshold
return Result(True, self, results)
return Result(False, self, results)
else:
results = [child.evaluate(ctx, short_circuit=short_circuit) for child in self.children]
# note that here we cast the child result as a bool
# because we've overridden `__bool__` above.
#
# we can't use `if child is True` because the instance is not True.
success = sum([1 for child in results if bool(child) is True]) >= self.count
return Result(success, self, results)
def evaluate(self, ctx):
results = [child.evaluate(ctx) for child in self.children]
# note that here we cast the child result as a bool
# because we've overridden `__bool__` above.
#
# we can't use `if child is True` because the instance is not True.
success = sum([1 for child in results if bool(child) is True]) >= self.count
return Result(success, self, results)
class Range(Statement):
"""match if the child is contained in the ctx set with a count in the given range."""
def __init__(self, child, min=None, max=None, description=None):
super().__init__(description=description)
super(Range, self).__init__(description=description)
self.child = child
self.min = min if min is not None else 0
self.max = max if max is not None else (1 << 64 - 1)
def evaluate(self, ctx, **kwargs):
capa.perf.counters["evaluate.feature"] += 1
capa.perf.counters["evaluate.feature.range"] += 1
def evaluate(self, ctx):
count = len(ctx.get(self.child, []))
if self.min == 0 and count == 0:
return Result(True, self, [])
@@ -234,9 +179,9 @@ class Range(Statement):
def __str__(self):
if self.max == (1 << 64 - 1):
return f"range({str(self.child)}, min={self.min}, max=infinity)"
return "range(%s, min=%d, max=infinity)" % (str(self.child), self.min)
else:
return f"range({str(self.child)}, min={self.min}, max={self.max})"
return "range(%s, min=%d, max=%d)" % (str(self.child), self.min, self.max)
class Subscope(Statement):
@@ -245,66 +190,59 @@ class Subscope(Statement):
the engine should preprocess rules to extract subscope statements into their own rules.
"""
def __init__(self, scope, child, description=None):
super().__init__(description=description)
def __init__(self, scope, child):
super(Subscope, self).__init__()
self.scope = scope
self.child = child
def evaluate(self, ctx, **kwargs):
def evaluate(self, ctx):
raise ValueError("cannot evaluate a subscope directly!")
# mapping from rule name to list of: (location of match, result object)
#
# used throughout matching and rendering to collection the results
# of statement evaluation and their locations.
#
# to check if a rule matched, do: `"TCP client" in matches`.
# to find where a rule matched, do: `map(first, matches["TCP client"])`
# to see how a rule matched, do:
#
# for address, match_details in matches["TCP client"]:
# inspect(match_details)
#
# aliased here so that the type can be documented and xref'd.
MatchResults = Mapping[str, List[Tuple[Address, Result]]]
def index_rule_matches(features: FeatureSet, rule: "capa.rules.Rule", locations: Iterable[Address]):
def topologically_order_rules(rules):
"""
record into the given featureset that the given rule matched at the given locations.
order the given rules such that dependencies show up before dependents.
this means that as we match rules, we can add features for the matches, and these
will be matched by subsequent rules if they follow this order.
naively, this is just adding a MatchedRule feature;
however, we also want to record matches for the rule's namespaces.
updates `features` in-place. doesn't modify the remaining arguments.
assumes that the rule dependency graph is a DAG.
"""
features[capa.features.common.MatchedRule(rule.name)].update(locations)
namespace = rule.meta.get("namespace")
if namespace:
while namespace:
features[capa.features.common.MatchedRule(namespace)].update(locations)
namespace, _, _ = namespace.rpartition("/")
# we evaluate `rules` multiple times, so if its a generator, realize it into a list.
rules = list(rules)
namespaces = capa.rules.index_rules_by_namespace(rules)
rules = {rule.name: rule for rule in rules}
seen = set([])
ret = []
def rec(rule):
if rule.name in seen:
return
for dep in rule.get_dependencies(namespaces):
rec(rules[dep])
ret.append(rule)
seen.add(rule.name)
for rule in rules.values():
rec(rule)
return ret
def match(rules: List["capa.rules.Rule"], features: FeatureSet, addr: Address) -> Tuple[FeatureSet, MatchResults]:
def match(rules, features, va):
"""
match the given rules against the given features,
returning an updated set of features and the matches.
Args:
rules (List[capa.rules.Rule]): these must already be ordered topologically by dependency.
features (Mapping[capa.features.Feature, int]):
va (int): location of the features
the updated features are just like the input,
but extended to include the match features (e.g. names of rules that matched).
the given feature set is not modified; an updated copy is returned.
the given list of rules must be ordered topologically by dependency,
or else `match` statements will not be handled correctly.
this routine should be fairly optimized, but is not guaranteed to be the fastest matcher possible.
it has a particularly convenient signature: (rules, features) -> matches
other strategies can be imagined that match differently; implement these elsewhere.
specifically, this routine does "top down" matching of the given rules against the feature set.
Returns:
Tuple[List[capa.features.Feature], Dict[str, Tuple[int, capa.engine.Result]]]: two-tuple with entries:
- list of features used for matching (which may be greater than argument, due to rule match features), and
- mapping from rule name to (location of match, result object)
"""
results = collections.defaultdict(list) # type: MatchResults
results = collections.defaultdict(list)
# copy features so that we can modify it
# without affecting the caller (keep this function pure)
@@ -313,22 +251,15 @@ def match(rules: List["capa.rules.Rule"], features: FeatureSet, addr: Address) -
features = collections.defaultdict(set, copy.copy(features))
for rule in rules:
res = rule.evaluate(features, short_circuit=True)
res = rule.evaluate(features)
if res:
# we first matched the rule with short circuiting enabled.
# this is much faster than without short circuiting.
# however, we want to collect all results thoroughly,
# so once we've found a match quickly,
# go back and capture results without short circuiting.
res = rule.evaluate(features, short_circuit=False)
results[rule.name].append((va, res))
features[capa.features.MatchedRule(rule.name)].add(va)
# sanity check
assert bool(res) is True
results[rule.name].append((addr, res))
# we need to update the current `features`
# because subsequent iterations of this loop may use newly added features,
# such as rule or namespace matches.
index_rule_matches(features, rule, [addr])
namespace = rule.meta.get("namespace")
if namespace:
while namespace:
features[capa.features.MatchedRule(namespace)].add(va)
namespace, _, _ = namespace.rpartition("/")
return (features, results)

View File

@@ -1,21 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
class UnsupportedRuntimeError(RuntimeError):
pass
class UnsupportedFormatError(ValueError):
pass
class UnsupportedArchError(ValueError):
pass
class UnsupportedOSError(ValueError):
pass

View File

@@ -0,0 +1,236 @@
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import re
import sys
import codecs
import logging
import capa.engine
logger = logging.getLogger(__name__)
MAX_BYTES_FEATURE_SIZE = 0x100
# thunks may be chained so we specify a delta to control the depth to which these chains are explored
THUNK_CHAIN_DEPTH_DELTA = 5
# identifiers for supported architectures names that tweak a feature
# for example, offset/x32
ARCH_X32 = "x32"
ARCH_X64 = "x64"
VALID_ARCH = (ARCH_X32, ARCH_X64)
def bytes_to_str(b):
if sys.version_info[0] >= 3:
return str(codecs.encode(b, "hex").decode("utf-8"))
else:
return codecs.encode(b, "hex")
def hex_string(h):
""" render hex string e.g. "0a40b1" as "0A 40 B1" """
return " ".join(h[i : i + 2] for i in range(0, len(h), 2)).upper()
def escape_string(s):
"""escape special characters"""
s = repr(s)
if not s.startswith(('"', "'")):
# u'hello\r\nworld' -> hello\\r\\nworld
s = s[2:-1]
else:
# 'hello\r\nworld' -> hello\\r\\nworld
s = s[1:-1]
s = s.replace("\\'", "'") # repr() may escape "'" in some edge cases, remove
s = s.replace('"', '\\"') # repr() does not escape '"', add
return s
class Feature(object):
def __init__(self, value, arch=None, description=None):
"""
Args:
value (any): the value of the feature, such as the number or string.
arch (str): one of the VALID_ARCH values, or None.
When None, then the feature applies to any architecture.
Modifies the feature name from `feature` to `feature/arch`, like `offset/x32`.
description (str): a human-readable description that explains the feature value.
"""
super(Feature, self).__init__()
if arch is not None:
if arch not in VALID_ARCH:
raise ValueError("arch '%s' must be one of %s" % (arch, VALID_ARCH))
self.name = self.__class__.__name__.lower() + "/" + arch
else:
self.name = self.__class__.__name__.lower()
self.value = value
self.arch = arch
self.description = description
def __hash__(self):
return hash((self.name, self.value, self.arch))
def __eq__(self, other):
return self.name == other.name and self.value == other.value and self.arch == other.arch
def get_value_str(self):
"""
render the value of this feature, for use by `__str__` and friends.
subclasses should override to customize the rendering.
Returns: any
"""
return self.value
def __str__(self):
if self.value is not None:
if self.description:
return "%s(%s = %s)" % (self.name, self.get_value_str(), self.description)
else:
return "%s(%s)" % (self.name, self.get_value_str())
else:
return "%s" % self.name
def __repr__(self):
return str(self)
def evaluate(self, ctx):
return capa.engine.Result(self in ctx, self, [], locations=ctx.get(self, []))
def freeze_serialize(self):
if self.arch is not None:
return (self.__class__.__name__, [self.value, {"arch": self.arch}])
else:
return (self.__class__.__name__, [self.value])
@classmethod
def freeze_deserialize(cls, args):
# as you can see below in code,
# if the last argument is a dictionary,
# consider it to be kwargs passed to the feature constructor.
if len(args) == 1:
return cls(*args)
elif isinstance(args[-1], dict):
kwargs = args[-1]
args = args[:-1]
return cls(*args, **kwargs)
class MatchedRule(Feature):
def __init__(self, value, description=None):
super(MatchedRule, self).__init__(value, description=description)
self.name = "match"
class Characteristic(Feature):
def __init__(self, value, description=None):
super(Characteristic, self).__init__(value, description=description)
class String(Feature):
def __init__(self, value, description=None):
super(String, self).__init__(value, description=description)
class Regex(String):
def __init__(self, value, description=None):
super(Regex, self).__init__(value, description=description)
pat = self.value[len("/") : -len("/")]
flags = re.DOTALL
if value.endswith("/i"):
pat = self.value[len("/") : -len("/i")]
flags |= re.IGNORECASE
try:
self.re = re.compile(pat, flags)
except re.error:
if value.endswith("/i"):
value = value[: -len("i")]
raise ValueError(
"invalid regular expression: %s it should use Python syntax, try it at https://pythex.org" % value
)
def evaluate(self, ctx):
for feature, locations in ctx.items():
if not isinstance(feature, (capa.features.String,)):
continue
# `re.search` finds a match anywhere in the given string
# which implies leading and/or trailing whitespace.
# using this mode cleans is more convenient for rule authors,
# so that they don't have to prefix/suffix their terms like: /.*foo.*/.
if self.re.search(feature.value):
# unlike other features, we cannot return put a reference to `self` directly in a `Result`.
# this is because `self` may match on many strings, so we can't stuff the matched value into it.
# instead, return a new instance that has a reference to both the regex and the matched value.
# see #262.
return capa.engine.Result(True, _MatchedRegex(self, feature.value), [], locations=locations)
return capa.engine.Result(False, _MatchedRegex(self, None), [])
def __str__(self):
return "regex(string =~ %s)" % self.value
class _MatchedRegex(Regex):
"""
this represents a specific instance of a regular expression feature match.
treat it the same as a `Regex` except it has the `match` field that contains the complete string that matched.
note: this type should only ever be constructed by `Regex.evaluate()`. it is not part of the public API.
"""
def __init__(self, regex, match):
"""
args:
regex (Regex): the regex feature that matches
match (string|None): the matching string or None if it doesn't match
"""
super(_MatchedRegex, self).__init__(regex.value, description=regex.description)
# we want this to collide with the name of `Regex` above,
# so that it works nicely with the renderers.
self.name = "regex"
# this may be None if the regex doesn't match
self.match = match
def __str__(self):
return 'regex(string =~ %s, matched = "%s")' % (self.value, self.match)
class StringFactory(object):
def __new__(self, value, description=None):
if value.startswith("/") and (value.endswith("/") or value.endswith("/i")):
return Regex(value, description=description)
return String(value, description=description)
class Bytes(Feature):
def __init__(self, value, description=None):
super(Bytes, self).__init__(value, description=description)
def evaluate(self, ctx):
for feature, locations in ctx.items():
if not isinstance(feature, (capa.features.Bytes,)):
continue
if feature.value.startswith(self.value):
return capa.engine.Result(True, self, [], locations=locations)
return capa.engine.Result(False, self, [])
def get_value_str(self):
return hex_string(bytes_to_str(self.value))
def freeze_serialize(self):
return (self.__class__.__name__, [bytes_to_str(self.value).upper()])
@classmethod
def freeze_deserialize(cls, args):
return cls(*[codecs.decode(x, "hex") for x in args])

View File

@@ -1,121 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import abc
class Address(abc.ABC):
@abc.abstractmethod
def __eq__(self, other):
...
@abc.abstractmethod
def __lt__(self, other):
# implement < so that addresses can be sorted from low to high
...
@abc.abstractmethod
def __hash__(self):
# implement hash so that addresses can be used in sets and dicts
...
@abc.abstractmethod
def __repr__(self):
# implement repr to help during debugging
...
class AbsoluteVirtualAddress(int, Address):
"""an absolute memory address"""
def __new__(cls, v):
assert v >= 0
return int.__new__(cls, v)
def __repr__(self):
return f"absolute(0x{self:x})"
def __hash__(self):
return int.__hash__(self)
class RelativeVirtualAddress(int, Address):
"""a memory address relative to a base address"""
def __repr__(self):
return f"relative(0x{self:x})"
def __hash__(self):
return int.__hash__(self)
class FileOffsetAddress(int, Address):
"""an address relative to the start of a file"""
def __new__(cls, v):
assert v >= 0
return int.__new__(cls, v)
def __repr__(self):
return f"file(0x{self:x})"
def __hash__(self):
return int.__hash__(self)
class DNTokenAddress(int, Address):
"""a .NET token"""
def __new__(cls, token: int):
return int.__new__(cls, token)
def __repr__(self):
return f"token(0x{self:x})"
def __hash__(self):
return int.__hash__(self)
class DNTokenOffsetAddress(Address):
"""an offset into an object specified by a .NET token"""
def __init__(self, token: int, offset: int):
assert offset >= 0
self.token = token
self.offset = offset
def __eq__(self, other):
return (self.token, self.offset) == (other.token, other.offset)
def __lt__(self, other):
return (self.token, self.offset) < (other.token, other.offset)
def __hash__(self):
return hash((self.token, self.offset))
def __repr__(self):
return f"token(0x{self.token:x})+(0x{self.offset:x})"
def __index__(self):
return self.token + self.offset
class _NoAddress(Address):
def __eq__(self, other):
return True
def __lt__(self, other):
return False
def __hash__(self):
return hash(0)
def __repr__(self):
return "no address"
NO_ADDRESS = _NoAddress()

View File

@@ -1,4 +1,4 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
@@ -6,15 +6,22 @@
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
from capa.features.common import Feature
from capa.features import Feature
class BasicBlock(Feature):
def __init__(self, description=None):
super().__init__(0, description=description)
def __init__(self):
super(BasicBlock, self).__init__(None)
def __str__(self):
return "basic block"
def get_value_str(self):
return ""
def freeze_serialize(self):
return (self.__class__.__name__, [])
@classmethod
def freeze_deserialize(cls, args):
return cls()

View File

@@ -1,476 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import re
import abc
import codecs
import typing
import logging
import collections
from typing import TYPE_CHECKING, Set, Dict, List, Union, Optional
if TYPE_CHECKING:
# circular import, otherwise
import capa.engine
import capa.perf
import capa.features
import capa.features.extractors.elf
from capa.features.address import Address
logger = logging.getLogger(__name__)
MAX_BYTES_FEATURE_SIZE = 0x100
# thunks may be chained so we specify a delta to control the depth to which these chains are explored
THUNK_CHAIN_DEPTH_DELTA = 5
class FeatureAccess:
READ = "read"
WRITE = "write"
VALID_FEATURE_ACCESS = (FeatureAccess.READ, FeatureAccess.WRITE)
def bytes_to_str(b: bytes) -> str:
return str(codecs.encode(b, "hex").decode("utf-8"))
def hex_string(h: str) -> str:
"""render hex string e.g. "0a40b1" as "0A 40 B1" """
return " ".join(h[i : i + 2] for i in range(0, len(h), 2)).upper()
def escape_string(s: str) -> str:
"""escape special characters"""
s = repr(s)
if not s.startswith(('"', "'")):
# u'hello\r\nworld' -> hello\\r\\nworld
s = s[2:-1]
else:
# 'hello\r\nworld' -> hello\\r\\nworld
s = s[1:-1]
s = s.replace("\\'", "'") # repr() may escape "'" in some edge cases, remove
s = s.replace('"', '\\"') # repr() does not escape '"', add
return s
class Result:
"""
represents the results of an evaluation of statements against features.
instances of this class should behave like a bool,
e.g. `assert Result(True, ...) == True`
instances track additional metadata about evaluation results.
they contain references to the statement node (e.g. an And statement),
as well as the children Result instances.
we need this so that we can render the tree of expressions and their results.
"""
def __init__(
self,
success: bool,
statement: Union["capa.engine.Statement", "Feature"],
children: List["Result"],
locations: Optional[Set[Address]] = None,
):
super().__init__()
self.success = success
self.statement = statement
self.children = children
self.locations = locations if locations is not None else set()
def __eq__(self, other):
if isinstance(other, bool):
return self.success == other
return False
def __bool__(self):
return self.success
def __nonzero__(self):
return self.success
class Feature(abc.ABC): # noqa: B024
# this is an abstract class, since we don't want anyone to instantiate it directly,
# but it doesn't have any abstract methods.
def __init__(
self,
value: Union[str, int, float, bytes],
description: Optional[str] = None,
):
"""
Args:
value (any): the value of the feature, such as the number or string.
description (str): a human-readable description that explains the feature value.
"""
super().__init__()
self.name = self.__class__.__name__.lower()
self.value = value
self.description = description
def __hash__(self):
return hash((self.name, self.value))
def __eq__(self, other):
return self.name == other.name and self.value == other.value
def __lt__(self, other):
# implementing sorting by serializing to JSON is a huge hack.
# its slow, inelegant, and probably doesn't work intuitively;
# however, we only use it for deterministic output, so it's good enough for now.
# circular import
# we should fix if this wasn't already a huge hack.
import capa.features.freeze.features
return (
capa.features.freeze.features.feature_from_capa(self).model_dump_json()
< capa.features.freeze.features.feature_from_capa(other).model_dump_json()
)
def get_name_str(self) -> str:
"""
render the name of this feature, for use by `__str__` and friends.
subclasses should override to customize the rendering.
"""
return self.name
def get_value_str(self) -> str:
"""
render the value of this feature, for use by `__str__` and friends.
subclasses should override to customize the rendering.
"""
return str(self.value)
def __str__(self):
if self.value is not None:
if self.description:
return f"{self.get_name_str()}({self.get_value_str()} = {self.description})"
else:
return f"{self.get_name_str()}({self.get_value_str()})"
else:
return f"{self.get_name_str()}"
def __repr__(self):
return str(self)
def evaluate(self, ctx: Dict["Feature", Set[Address]], **kwargs) -> Result:
capa.perf.counters["evaluate.feature"] += 1
capa.perf.counters["evaluate.feature." + self.name] += 1
return Result(self in ctx, self, [], locations=ctx.get(self, set()))
class MatchedRule(Feature):
def __init__(self, value: str, description=None):
super().__init__(value, description=description)
self.name = "match"
class Characteristic(Feature):
def __init__(self, value: str, description=None):
super().__init__(value, description=description)
class String(Feature):
def __init__(self, value: str, description=None):
super().__init__(value, description=description)
def get_value_str(self) -> str:
assert isinstance(self.value, str)
return escape_string(self.value)
class Class(Feature):
def __init__(self, value: str, description=None):
super().__init__(value, description=description)
class Namespace(Feature):
def __init__(self, value: str, description=None):
super().__init__(value, description=description)
class Substring(String):
def __init__(self, value: str, description=None):
super().__init__(value, description=description)
self.value = value
def evaluate(self, ctx, short_circuit=True):
capa.perf.counters["evaluate.feature"] += 1
capa.perf.counters["evaluate.feature.substring"] += 1
# mapping from string value to list of locations.
# will unique the locations later on.
matches: typing.DefaultDict[str, Set[Address]] = collections.defaultdict(set)
assert isinstance(self.value, str)
for feature, locations in ctx.items():
if not isinstance(feature, (String,)):
continue
if not isinstance(feature.value, str):
# this is a programming error: String should only contain str
raise ValueError("unexpected feature value type")
if self.value in feature.value:
matches[feature.value].update(locations)
if short_circuit:
# we found one matching string, thats sufficient to match.
# don't collect other matching strings in this mode.
break
if matches:
# collect all locations
locations = set()
for locs in matches.values():
locations.update(locs)
# unlike other features, we cannot return put a reference to `self` directly in a `Result`.
# this is because `self` may match on many strings, so we can't stuff the matched value into it.
# instead, return a new instance that has a reference to both the substring and the matched values.
return Result(True, _MatchedSubstring(self, dict(matches)), [], locations=locations)
else:
return Result(False, _MatchedSubstring(self, {}), [])
def get_value_str(self) -> str:
assert isinstance(self.value, str)
return escape_string(self.value)
def __str__(self):
assert isinstance(self.value, str)
return f"substring({escape_string(self.value)})"
class _MatchedSubstring(Substring):
"""
this represents specific match instances of a substring feature.
treat it the same as a `Substring` except it has the `matches` field that contains the complete strings that matched.
note: this type should only ever be constructed by `Substring.evaluate()`. it is not part of the public API.
"""
def __init__(self, substring: Substring, matches: Dict[str, Set[Address]]):
"""
args:
substring: the substring feature that matches.
match: mapping from matching string to its locations.
"""
super().__init__(str(substring.value), description=substring.description)
# we want this to collide with the name of `Substring` above,
# so that it works nicely with the renderers.
self.name = "substring"
# this may be None if the substring doesn't match
self.matches = matches
def __str__(self):
matches = ", ".join(f'"{s}"' for s in (self.matches or {}).keys())
assert isinstance(self.value, str)
return f'substring("{self.value}", matches = {matches})'
class Regex(String):
def __init__(self, value: str, description=None):
super().__init__(value, description=description)
self.value = value
pat = self.value[len("/") : -len("/")]
flags = re.DOTALL
if value.endswith("/i"):
pat = self.value[len("/") : -len("/i")]
flags |= re.IGNORECASE
try:
self.re = re.compile(pat, flags)
except re.error as exc:
if value.endswith("/i"):
value = value[: -len("i")]
raise ValueError(
f"invalid regular expression: {value} it should use Python syntax, try it at https://pythex.org"
) from exc
def evaluate(self, ctx, short_circuit=True):
capa.perf.counters["evaluate.feature"] += 1
capa.perf.counters["evaluate.feature.regex"] += 1
# mapping from string value to list of locations.
# will unique the locations later on.
matches: typing.DefaultDict[str, Set[Address]] = collections.defaultdict(set)
for feature, locations in ctx.items():
if not isinstance(feature, (String,)):
continue
if not isinstance(feature.value, str):
# this is a programming error: String should only contain str
raise ValueError("unexpected feature value type")
# `re.search` finds a match anywhere in the given string
# which implies leading and/or trailing whitespace.
# using this mode cleans is more convenient for rule authors,
# so that they don't have to prefix/suffix their terms like: /.*foo.*/.
if self.re.search(feature.value):
matches[feature.value].update(locations)
if short_circuit:
# we found one matching string, thats sufficient to match.
# don't collect other matching strings in this mode.
break
if matches:
# collect all locations
locations = set()
for locs in matches.values():
locations.update(locs)
# unlike other features, we cannot return put a reference to `self` directly in a `Result`.
# this is because `self` may match on many strings, so we can't stuff the matched value into it.
# instead, return a new instance that has a reference to both the regex and the matched values.
# see #262.
return Result(True, _MatchedRegex(self, dict(matches)), [], locations=locations)
else:
return Result(False, _MatchedRegex(self, {}), [])
def __str__(self):
assert isinstance(self.value, str)
return f"regex(string =~ {self.value})"
class _MatchedRegex(Regex):
"""
this represents specific match instances of a regular expression feature.
treat it the same as a `Regex` except it has the `matches` field that contains the complete strings that matched.
note: this type should only ever be constructed by `Regex.evaluate()`. it is not part of the public API.
"""
def __init__(self, regex: Regex, matches: Dict[str, Set[Address]]):
"""
args:
regex: the regex feature that matches.
matches: mapping from matching string to its locations.
"""
super().__init__(str(regex.value), description=regex.description)
# we want this to collide with the name of `Regex` above,
# so that it works nicely with the renderers.
self.name = "regex"
# this may be None if the regex doesn't match
self.matches = matches
def __str__(self):
matches = ", ".join(f'"{s}"' for s in (self.matches or {}).keys())
assert isinstance(self.value, str)
return f"regex(string =~ {self.value}, matches = {matches})"
class StringFactory:
def __new__(cls, value: str, description=None):
if value.startswith("/") and (value.endswith("/") or value.endswith("/i")):
return Regex(value, description=description)
return String(value, description=description)
class Bytes(Feature):
def __init__(self, value: bytes, description=None):
super().__init__(value, description=description)
self.value = value
def evaluate(self, ctx, **kwargs):
capa.perf.counters["evaluate.feature"] += 1
capa.perf.counters["evaluate.feature.bytes"] += 1
assert isinstance(self.value, bytes)
for feature, locations in ctx.items():
if not isinstance(feature, (Bytes,)):
continue
assert isinstance(feature.value, bytes)
if feature.value.startswith(self.value):
return Result(True, self, [], locations=locations)
return Result(False, self, [])
def get_value_str(self):
assert isinstance(self.value, bytes)
return hex_string(bytes_to_str(self.value))
# other candidates here: https://docs.microsoft.com/en-us/windows/win32/debug/pe-format#machine-types
ARCH_I386 = "i386"
ARCH_AMD64 = "amd64"
# dotnet
ARCH_ANY = "any"
VALID_ARCH = (ARCH_I386, ARCH_AMD64, ARCH_ANY)
class Arch(Feature):
def __init__(self, value: str, description=None):
super().__init__(value, description=description)
self.name = "arch"
OS_WINDOWS = "windows"
OS_LINUX = "linux"
OS_MACOS = "macos"
# dotnet
OS_ANY = "any"
VALID_OS = {os.value for os in capa.features.extractors.elf.OS}
VALID_OS.update({OS_WINDOWS, OS_LINUX, OS_MACOS, OS_ANY})
# internal only, not to be used in rules
OS_AUTO = "auto"
class OS(Feature):
def __init__(self, value: str, description=None):
super().__init__(value, description=description)
self.name = "os"
def evaluate(self, ctx, **kwargs):
capa.perf.counters["evaluate.feature"] += 1
capa.perf.counters["evaluate.feature." + self.name] += 1
for feature, locations in ctx.items():
if not isinstance(feature, (OS,)):
continue
assert isinstance(feature.value, str)
if OS_ANY in (self.value, feature.value) or self.value == feature.value:
return Result(True, self, [], locations=locations)
return Result(False, self, [])
FORMAT_PE = "pe"
FORMAT_ELF = "elf"
FORMAT_DOTNET = "dotnet"
VALID_FORMAT = (FORMAT_PE, FORMAT_ELF, FORMAT_DOTNET)
# internal only, not to be used in rules
FORMAT_AUTO = "auto"
FORMAT_SC32 = "sc32"
FORMAT_SC64 = "sc64"
FORMAT_FREEZE = "freeze"
FORMAT_RESULT = "result"
FORMAT_UNKNOWN = "unknown"
class Format(Feature):
def __init__(self, value: str, description=None):
super().__init__(value, description=description)
self.name = "format"
def is_global_feature(feature):
"""
is this a feature that is extracted at every scope?
today, these are OS and arch features.
"""
return isinstance(feature, (OS, Arch))

View File

@@ -0,0 +1,286 @@
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import abc
class FeatureExtractor(object):
"""
FeatureExtractor defines the interface for fetching features from a sample.
There may be multiple backends that support fetching features for capa.
For example, we use vivisect by default, but also want to support saving
and restoring features from a JSON file.
When we restore the features, we'd like to use exactly the same matching logic
to find matching rules.
Therefore, we can define a FeatureExtractor that provides features from the
serialized JSON file and do matching without a binary analysis pass.
Also, this provides a way to hook in an IDA backend.
This class is not instantiated directly; it is the base class for other implementations.
"""
__metaclass__ = abc.ABCMeta
def __init__(self):
#
# note: a subclass should define ctor parameters for its own use.
# for example, the Vivisect feature extract might require the vw and/or path.
# this base class doesn't know what to do with that info, though.
#
super(FeatureExtractor, self).__init__()
@abc.abstractmethod
def get_base_address(self):
"""
fetch the preferred load address at which the sample was analyzed.
returns: int
"""
raise NotImplemented
@abc.abstractmethod
def extract_file_features(self):
"""
extract file-scope features.
example::
extractor = VivisectFeatureExtractor(vw, path)
for feature, va in extractor.get_file_features():
print('0x%x: %s', va, feature)
yields:
Tuple[capa.features.Feature, int]: feature and its location
"""
raise NotImplemented
@abc.abstractmethod
def get_functions(self):
"""
enumerate the functions and provide opaque values that will
subsequently be provided to `.extract_function_features()`, etc.
by "opaque value", we mean that this can be any object, as long as it
provides enough context to `.extract_function_features()`.
the opaque value should support casting to int (`__int__`) for the function start address.
yields:
any: the opaque function value.
"""
raise NotImplemented
@abc.abstractmethod
def extract_function_features(self, f):
"""
extract function-scope features.
the arguments are opaque values previously provided by `.get_functions()`, etc.
example::
extractor = VivisectFeatureExtractor(vw, path)
for function in extractor.get_functions():
for feature, va in extractor.extract_function_features(function):
print('0x%x: %s', va, feature)
args:
f [any]: an opaque value previously fetched from `.get_functions()`.
yields:
Tuple[capa.features.Feature, int]: feature and its location
"""
raise NotImplemented
@abc.abstractmethod
def get_basic_blocks(self, f):
"""
enumerate the basic blocks in the given function and provide opaque values that will
subsequently be provided to `.extract_basic_block_features()`, etc.
by "opaque value", we mean that this can be any object, as long as it
provides enough context to `.extract_basic_block_features()`.
the opaque value should support casting to int (`__int__`) for the basic block start address.
yields:
any: the opaque basic block value.
"""
raise NotImplemented
@abc.abstractmethod
def extract_basic_block_features(self, f, bb):
"""
extract basic block-scope features.
the arguments are opaque values previously provided by `.get_functions()`, etc.
example::
extractor = VivisectFeatureExtractor(vw, path)
for function in extractor.get_functions():
for bb in extractor.get_basic_blocks(function):
for feature, va in extractor.extract_basic_block_features(function, bb):
print('0x%x: %s', va, feature)
args:
f [any]: an opaque value previously fetched from `.get_functions()`.
bb [any]: an opaque value previously fetched from `.get_basic_blocks()`.
yields:
Tuple[capa.features.Feature, int]: feature and its location
"""
raise NotImplemented
@abc.abstractmethod
def get_instructions(self, f, bb):
"""
enumerate the instructions in the given basic block and provide opaque values that will
subsequently be provided to `.extract_insn_features()`, etc.
by "opaque value", we mean that this can be any object, as long as it
provides enough context to `.extract_insn_features()`.
the opaque value should support casting to int (`__int__`) for the instruction address.
yields:
any: the opaque function value.
"""
raise NotImplemented
@abc.abstractmethod
def extract_insn_features(self, f, bb, insn):
"""
extract instruction-scope features.
the arguments are opaque values previously provided by `.get_functions()`, etc.
example::
extractor = VivisectFeatureExtractor(vw, path)
for function in extractor.get_functions():
for bb in extractor.get_basic_blocks(function):
for insn in extractor.get_instructions(function, bb):
for feature, va in extractor.extract_insn_features(function, bb, insn):
print('0x%x: %s', va, feature)
args:
f [any]: an opaque value previously fetched from `.get_functions()`.
bb [any]: an opaque value previously fetched from `.get_basic_blocks()`.
insn [any]: an opaque value previously fetched from `.get_instructions()`.
yields:
Tuple[capa.features.Feature, int]: feature and its location
"""
raise NotImplemented
class NullFeatureExtractor(FeatureExtractor):
"""
An extractor that extracts some user-provided features.
The structure of the single parameter is demonstrated in the example below.
This is useful for testing, as we can provide expected values and see if matching works.
Also, this is how we represent features deserialized from a freeze file.
example::
extractor = NullFeatureExtractor({
'base address: 0x401000,
'file features': [
(0x402345, capa.features.Characteristic('embedded pe')),
],
'functions': {
0x401000: {
'features': [
(0x401000, capa.features.Characteristic('nzxor')),
],
'basic blocks': {
0x401000: {
'features': [
(0x401000, capa.features.Characteristic('tight-loop')),
],
'instructions': {
0x401000: {
'features': [
(0x401000, capa.features.Characteristic('nzxor')),
],
},
0x401002: ...
}
},
0x401005: ...
}
},
0x40200: ...
}
)
"""
def __init__(self, features):
super(NullFeatureExtractor, self).__init__()
self.features = features
def get_base_address(self):
return self.features["base address"]
def extract_file_features(self):
for p in self.features.get("file features", []):
va, feature = p
yield feature, va
def get_functions(self):
for va in sorted(self.features["functions"].keys()):
yield va
def extract_function_features(self, f):
for p in self.features.get("functions", {}).get(f, {}).get("features", []): # noqa: E127 line over-indented
va, feature = p
yield feature, va
def get_basic_blocks(self, f):
for va in sorted(
self.features.get("functions", {}) # noqa: E127 line over-indented
.get(f, {})
.get("basic blocks", {})
.keys()
):
yield va
def extract_basic_block_features(self, f, bb):
for p in (
self.features.get("functions", {}) # noqa: E127 line over-indented
.get(f, {})
.get("basic blocks", {})
.get(bb, {})
.get("features", [])
):
va, feature = p
yield feature, va
def get_instructions(self, f, bb):
for va in sorted(
self.features.get("functions", {}) # noqa: E127 line over-indented
.get(f, {})
.get("basic blocks", {})
.get(bb, {})
.get("instructions", {})
.keys()
):
yield va
def extract_insn_features(self, f, bb, insn):
for p in (
self.features.get("functions", {}) # noqa: E127 line over-indented
.get(f, {})
.get("basic blocks", {})
.get(bb, {})
.get("instructions", {})
.get(insn, {})
.get("features", [])
):
va, feature = p
yield feature, va

View File

@@ -1,264 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import abc
import dataclasses
from typing import Any, Dict, Tuple, Union, Iterator
from dataclasses import dataclass
import capa.features.address
from capa.features.common import Feature
from capa.features.address import Address, AbsoluteVirtualAddress
# feature extractors may reference functions, BBs, insns by opaque handle values.
# you can use the `.address` property to get and render the address of the feature.
#
# these handles are only consumed by routines on
# the feature extractor from which they were created.
@dataclass
class FunctionHandle:
"""reference to a function recognized by a feature extractor.
Attributes:
address: the address of the function.
inner: extractor-specific data.
ctx: a context object for the extractor.
"""
address: Address
inner: Any
ctx: Dict[str, Any] = dataclasses.field(default_factory=dict)
@dataclass
class BBHandle:
"""reference to a basic block recognized by a feature extractor.
Attributes:
address: the address of the basic block start address.
inner: extractor-specific data.
"""
address: Address
inner: Any
@dataclass
class InsnHandle:
"""reference to a instruction recognized by a feature extractor.
Attributes:
address: the address of the instruction address.
inner: extractor-specific data.
"""
address: Address
inner: Any
class FeatureExtractor:
"""
FeatureExtractor defines the interface for fetching features from a sample.
There may be multiple backends that support fetching features for capa.
For example, we use vivisect by default, but also want to support saving
and restoring features from a JSON file.
When we restore the features, we'd like to use exactly the same matching logic
to find matching rules.
Therefore, we can define a FeatureExtractor that provides features from the
serialized JSON file and do matching without a binary analysis pass.
Also, this provides a way to hook in an IDA backend.
This class is not instantiated directly; it is the base class for other implementations.
"""
__metaclass__ = abc.ABCMeta
def __init__(self):
#
# note: a subclass should define ctor parameters for its own use.
# for example, the Vivisect feature extract might require the vw and/or path.
# this base class doesn't know what to do with that info, though.
#
super().__init__()
@abc.abstractmethod
def get_base_address(self) -> Union[AbsoluteVirtualAddress, capa.features.address._NoAddress]:
"""
fetch the preferred load address at which the sample was analyzed.
when the base address is `NO_ADDRESS`, then the loader has no concept of a preferred load address.
such as: shellcode, .NET modules, etc.
in these scenarios, RelativeVirtualAddresses aren't used.
"""
raise NotImplementedError()
@abc.abstractmethod
def extract_global_features(self) -> Iterator[Tuple[Feature, Address]]:
"""
extract features found at every scope ("global").
example::
extractor = VivisectFeatureExtractor(vw, path)
for feature, va in extractor.get_global_features():
print('0x%x: %s', va, feature)
yields:
Tuple[Feature, Address]: feature and its location
"""
raise NotImplementedError()
@abc.abstractmethod
def extract_file_features(self) -> Iterator[Tuple[Feature, Address]]:
"""
extract file-scope features.
example::
extractor = VivisectFeatureExtractor(vw, path)
for feature, va in extractor.get_file_features():
print('0x%x: %s', va, feature)
yields:
Tuple[Feature, Address]: feature and its location
"""
raise NotImplementedError()
@abc.abstractmethod
def get_functions(self) -> Iterator[FunctionHandle]:
"""
enumerate the functions and provide opaque values that will
subsequently be provided to `.extract_function_features()`, etc.
"""
raise NotImplementedError()
def is_library_function(self, addr: Address) -> bool:
"""
is the given address a library function?
the backend may implement its own function matching algorithm, or none at all.
we accept an address here, rather than function object,
to handle addresses identified in instructions.
this information is used to:
- filter out matches in library functions (by default), and
- recognize when to fetch symbol names for called (non-API) functions
args:
addr (Address): the address of a function.
returns:
bool: True if the given address is the start of a library function.
"""
return False
def get_function_name(self, addr: Address) -> str:
"""
fetch any recognized name for the given address.
this is only guaranteed to return a value when the given function is a recognized library function.
we accept a VA here, rather than function object, to handle addresses identified in instructions.
args:
addr (Address): the address of a function.
returns:
str: the function name
raises:
KeyError: when the given function does not have a name.
"""
raise KeyError(addr)
@abc.abstractmethod
def extract_function_features(self, f: FunctionHandle) -> Iterator[Tuple[Feature, Address]]:
"""
extract function-scope features.
the arguments are opaque values previously provided by `.get_functions()`, etc.
example::
extractor = VivisectFeatureExtractor(vw, path)
for function in extractor.get_functions():
for feature, address in extractor.extract_function_features(function):
print('0x%x: %s', address, feature)
args:
f [FunctionHandle]: an opaque value previously fetched from `.get_functions()`.
yields:
Tuple[Feature, Address]: feature and its location
"""
raise NotImplementedError()
@abc.abstractmethod
def get_basic_blocks(self, f: FunctionHandle) -> Iterator[BBHandle]:
"""
enumerate the basic blocks in the given function and provide opaque values that will
subsequently be provided to `.extract_basic_block_features()`, etc.
"""
raise NotImplementedError()
@abc.abstractmethod
def extract_basic_block_features(self, f: FunctionHandle, bb: BBHandle) -> Iterator[Tuple[Feature, Address]]:
"""
extract basic block-scope features.
the arguments are opaque values previously provided by `.get_functions()`, etc.
example::
extractor = VivisectFeatureExtractor(vw, path)
for function in extractor.get_functions():
for bb in extractor.get_basic_blocks(function):
for feature, address in extractor.extract_basic_block_features(function, bb):
print('0x%x: %s', address, feature)
args:
f [FunctionHandle]: an opaque value previously fetched from `.get_functions()`.
bb [BBHandle]: an opaque value previously fetched from `.get_basic_blocks()`.
yields:
Tuple[Feature, Address]: feature and its location
"""
raise NotImplementedError()
@abc.abstractmethod
def get_instructions(self, f: FunctionHandle, bb: BBHandle) -> Iterator[InsnHandle]:
"""
enumerate the instructions in the given basic block and provide opaque values that will
subsequently be provided to `.extract_insn_features()`, etc.
"""
raise NotImplementedError()
@abc.abstractmethod
def extract_insn_features(
self, f: FunctionHandle, bb: BBHandle, insn: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
"""
extract instruction-scope features.
the arguments are opaque values previously provided by `.get_functions()`, etc.
example::
extractor = VivisectFeatureExtractor(vw, path)
for function in extractor.get_functions():
for bb in extractor.get_basic_blocks(function):
for insn in extractor.get_instructions(function, bb):
for feature, address in extractor.extract_insn_features(function, bb, insn):
print('0x%x: %s', address, feature)
args:
f [FunctionHandle]: an opaque value previously fetched from `.get_functions()`.
bb [BBHandle]: an opaque value previously fetched from `.get_basic_blocks()`.
insn [InsnHandle]: an opaque value previously fetched from `.get_instructions()`.
yields:
Tuple[Feature, Address]: feature and its location
"""
raise NotImplementedError()

View File

@@ -1,184 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import string
import struct
from typing import Tuple, Iterator
from binaryninja import Function, Settings
from binaryninja import BasicBlock as BinjaBasicBlock
from binaryninja import (
BinaryView,
SymbolType,
RegisterValueType,
VariableSourceType,
MediumLevelILSetVar,
MediumLevelILOperation,
MediumLevelILBasicBlock,
MediumLevelILInstruction,
)
from capa.features.common import Feature, Characteristic
from capa.features.address import Address
from capa.features.basicblock import BasicBlock
from capa.features.extractors.helpers import MIN_STACKSTRING_LEN
from capa.features.extractors.base_extractor import BBHandle, FunctionHandle
use_const_outline: bool = False
settings: Settings = Settings()
if settings.contains("analysis.outlining.builtins") and settings.get_bool("analysis.outlining.builtins"):
use_const_outline = True
def get_printable_len_ascii(s: bytes) -> int:
"""Return string length if all operand bytes are ascii or utf16-le printable"""
count = 0
for c in s:
if c == 0:
return count
if c < 127 and chr(c) in string.printable:
count += 1
return count
def get_printable_len_wide(s: bytes) -> int:
"""Return string length if all operand bytes are ascii or utf16-le printable"""
if all(c == 0x00 for c in s[1::2]):
return get_printable_len_ascii(s[::2])
return 0
def get_stack_string_len(f: Function, il: MediumLevelILInstruction) -> int:
bv: BinaryView = f.view
if il.operation != MediumLevelILOperation.MLIL_CALL:
return 0
target = il.dest
if target.operation not in [MediumLevelILOperation.MLIL_CONST, MediumLevelILOperation.MLIL_CONST_PTR]:
return 0
addr = target.value.value
sym = bv.get_symbol_at(addr)
if not sym or sym.type != SymbolType.LibraryFunctionSymbol:
return 0
if sym.name not in ["__builtin_strncpy", "__builtin_strcpy", "__builtin_wcscpy"]:
return 0
if len(il.params) < 2:
return 0
dest = il.params[0]
if dest.operation in [MediumLevelILOperation.MLIL_ADDRESS_OF, MediumLevelILOperation.MLIL_VAR]:
var = dest.src
else:
return 0
if var.source_type != VariableSourceType.StackVariableSourceType:
return 0
src = il.params[1]
if src.value.type != RegisterValueType.ConstantDataAggregateValue:
return 0
s = f.get_constant_data(RegisterValueType.ConstantDataAggregateValue, src.value.value)
return max(get_printable_len_ascii(bytes(s)), get_printable_len_wide(bytes(s)))
def get_printable_len(il: MediumLevelILSetVar) -> int:
"""Return string length if all operand bytes are ascii or utf16-le printable"""
width = il.dest.type.width
value = il.src.value.value
if width == 1:
chars = struct.pack("<B", value & 0xFF)
elif width == 2:
chars = struct.pack("<H", value & 0xFFFF)
elif width == 4:
chars = struct.pack("<I", value & 0xFFFFFFFF)
elif width == 8:
chars = struct.pack("<Q", value & 0xFFFFFFFFFFFFFFFF)
else:
return 0
def is_printable_ascii(chars_: bytes):
return all(c < 127 and chr(c) in string.printable for c in chars_)
def is_printable_utf16le(chars_: bytes):
if all(c == 0x00 for c in chars_[1::2]):
return is_printable_ascii(chars_[::2])
if is_printable_ascii(chars):
return width
if is_printable_utf16le(chars):
return width // 2
return 0
def is_mov_imm_to_stack(il: MediumLevelILInstruction) -> bool:
"""verify instruction moves immediate onto stack"""
if il.operation != MediumLevelILOperation.MLIL_SET_VAR:
return False
if il.src.operation != MediumLevelILOperation.MLIL_CONST:
return False
if il.dest.source_type != VariableSourceType.StackVariableSourceType:
return False
return True
def bb_contains_stackstring(f: Function, bb: MediumLevelILBasicBlock) -> bool:
"""check basic block for stackstring indicators
true if basic block contains enough moves of constant bytes to the stack
"""
count = 0
for il in bb:
if use_const_outline:
count += get_stack_string_len(f, il)
else:
if is_mov_imm_to_stack(il):
count += get_printable_len(il)
if count > MIN_STACKSTRING_LEN:
return True
return False
def extract_bb_stackstring(fh: FunctionHandle, bbh: BBHandle) -> Iterator[Tuple[Feature, Address]]:
"""extract stackstring indicators from basic block"""
bb: Tuple[BinjaBasicBlock, MediumLevelILBasicBlock] = bbh.inner
if bb[1] is not None and bb_contains_stackstring(fh.inner, bb[1]):
yield Characteristic("stack string"), bbh.address
def extract_bb_tight_loop(fh: FunctionHandle, bbh: BBHandle) -> Iterator[Tuple[Feature, Address]]:
"""extract tight loop indicators from a basic block"""
bb: Tuple[BinjaBasicBlock, MediumLevelILBasicBlock] = bbh.inner
for edge in bb[0].outgoing_edges:
if edge.target.start == bb[0].start:
yield Characteristic("tight loop"), bbh.address
def extract_features(fh: FunctionHandle, bbh: BBHandle) -> Iterator[Tuple[Feature, Address]]:
"""extract basic block features"""
for bb_handler in BASIC_BLOCK_HANDLERS:
for feature, addr in bb_handler(fh, bbh):
yield feature, addr
yield BasicBlock(), bbh.address
BASIC_BLOCK_HANDLERS = (
extract_bb_tight_loop,
extract_bb_stackstring,
)

View File

@@ -1,75 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
from typing import List, Tuple, Iterator
import binaryninja as binja
import capa.features.extractors.elf
import capa.features.extractors.binja.file
import capa.features.extractors.binja.insn
import capa.features.extractors.binja.global_
import capa.features.extractors.binja.function
import capa.features.extractors.binja.basicblock
from capa.features.common import Feature
from capa.features.address import Address, AbsoluteVirtualAddress
from capa.features.extractors.base_extractor import BBHandle, InsnHandle, FunctionHandle, FeatureExtractor
class BinjaFeatureExtractor(FeatureExtractor):
def __init__(self, bv: binja.BinaryView):
super().__init__()
self.bv = bv
self.global_features: List[Tuple[Feature, Address]] = []
self.global_features.extend(capa.features.extractors.binja.file.extract_file_format(self.bv))
self.global_features.extend(capa.features.extractors.binja.global_.extract_os(self.bv))
self.global_features.extend(capa.features.extractors.binja.global_.extract_arch(self.bv))
def get_base_address(self):
return AbsoluteVirtualAddress(self.bv.start)
def extract_global_features(self):
yield from self.global_features
def extract_file_features(self):
yield from capa.features.extractors.binja.file.extract_features(self.bv)
def get_functions(self) -> Iterator[FunctionHandle]:
for f in self.bv.functions:
yield FunctionHandle(address=AbsoluteVirtualAddress(f.start), inner=f)
def extract_function_features(self, fh: FunctionHandle) -> Iterator[Tuple[Feature, Address]]:
yield from capa.features.extractors.binja.function.extract_features(fh)
def get_basic_blocks(self, fh: FunctionHandle) -> Iterator[BBHandle]:
f: binja.Function = fh.inner
# Set up a MLIL basic block dict look up to associate the disassembly basic block with its MLIL basic block
mlil_lookup = {}
for mlil_bb in f.mlil.basic_blocks:
mlil_lookup[mlil_bb.source_block.start] = mlil_bb
for bb in f.basic_blocks:
mlil_bb = mlil_lookup.get(bb.start)
yield BBHandle(address=AbsoluteVirtualAddress(bb.start), inner=(bb, mlil_bb))
def extract_basic_block_features(self, fh: FunctionHandle, bbh: BBHandle) -> Iterator[Tuple[Feature, Address]]:
yield from capa.features.extractors.binja.basicblock.extract_features(fh, bbh)
def get_instructions(self, fh: FunctionHandle, bbh: BBHandle) -> Iterator[InsnHandle]:
import capa.features.extractors.binja.helpers as binja_helpers
bb: Tuple[binja.BasicBlock, binja.MediumLevelILBasicBlock] = bbh.inner
addr = bb[0].start
for text, length in bb[0]:
insn = binja_helpers.DisassemblyInstruction(addr, length, text)
yield InsnHandle(address=AbsoluteVirtualAddress(addr), inner=insn)
addr += length
def extract_insn_features(self, fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle):
yield from capa.features.extractors.binja.insn.extract_features(fh, bbh, ih)

View File

@@ -1,187 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import struct
from typing import Tuple, Iterator
from binaryninja import Segment, BinaryView, SymbolType, SymbolBinding
import capa.features.extractors.common
import capa.features.extractors.helpers
import capa.features.extractors.strings
from capa.features.file import Export, Import, Section, FunctionName
from capa.features.common import FORMAT_PE, FORMAT_ELF, Format, String, Feature, Characteristic
from capa.features.address import NO_ADDRESS, Address, FileOffsetAddress, AbsoluteVirtualAddress
from capa.features.extractors.binja.helpers import read_c_string, unmangle_c_name
def check_segment_for_pe(bv: BinaryView, seg: Segment) -> Iterator[Tuple[int, int]]:
"""check segment for embedded PE
adapted for binja from:
https://github.com/vivisect/vivisect/blob/7be4037b1cecc4551b397f840405a1fc606f9b53/PE/carve.py#L19
"""
mz_xor = [
(
capa.features.extractors.helpers.xor_static(b"MZ", i),
capa.features.extractors.helpers.xor_static(b"PE", i),
i,
)
for i in range(256)
]
todo = []
# If this is the first segment of the binary, skip the first bytes. Otherwise, there will always be a matched
# PE at the start of the binaryview.
start = seg.start
if bv.view_type == "PE" and start == bv.start:
start += 1
for mzx, pex, i in mz_xor:
for off, _ in bv.find_all_data(start, seg.end, mzx):
todo.append((off, mzx, pex, i))
while len(todo):
off, mzx, pex, i = todo.pop()
# The MZ header has one field we will check e_lfanew is at 0x3c
e_lfanew = off + 0x3C
if seg.end < (e_lfanew + 4):
continue
newoff = struct.unpack("<I", capa.features.extractors.helpers.xor_static(bv.read(e_lfanew, 4), i))[0]
peoff = off + newoff
if seg.end < (peoff + 2):
continue
if bv.read(peoff, 2) == pex:
yield off, i
def extract_file_embedded_pe(bv: BinaryView) -> Iterator[Tuple[Feature, Address]]:
"""extract embedded PE features"""
for seg in bv.segments:
for ea, _ in check_segment_for_pe(bv, seg):
yield Characteristic("embedded pe"), FileOffsetAddress(ea)
def extract_file_export_names(bv: BinaryView) -> Iterator[Tuple[Feature, Address]]:
"""extract function exports"""
for sym in bv.get_symbols_of_type(SymbolType.FunctionSymbol):
if sym.binding in [SymbolBinding.GlobalBinding, SymbolBinding.WeakBinding]:
name = sym.short_name
yield Export(name), AbsoluteVirtualAddress(sym.address)
unmangled_name = unmangle_c_name(name)
if name != unmangled_name:
yield Export(unmangled_name), AbsoluteVirtualAddress(sym.address)
for sym in bv.get_symbols_of_type(SymbolType.DataSymbol):
if sym.binding not in [SymbolBinding.GlobalBinding]:
continue
name = sym.short_name
if not name.startswith("__forwarder_name"):
continue
# Due to https://github.com/Vector35/binaryninja-api/issues/4641, in binja version 3.5, the symbol's name
# does not contain the DLL name. As a workaround, we read the C string at the symbol's address, which contains
# both the DLL name and the function name.
# Once the above issue is closed in the next binjs stable release, we can update the code here to use the
# symbol name directly.
name = read_c_string(bv, sym.address, 1024)
forwarded_name = capa.features.extractors.helpers.reformat_forwarded_export_name(name)
yield Export(forwarded_name), AbsoluteVirtualAddress(sym.address)
yield Characteristic("forwarded export"), AbsoluteVirtualAddress(sym.address)
def extract_file_import_names(bv: BinaryView) -> Iterator[Tuple[Feature, Address]]:
"""extract function imports
1. imports by ordinal:
- modulename.#ordinal
2. imports by name, results in two features to support importname-only
matching:
- modulename.importname
- importname
"""
for sym in bv.get_symbols_of_type(SymbolType.ImportAddressSymbol):
lib_name = str(sym.namespace)
addr = AbsoluteVirtualAddress(sym.address)
for name in capa.features.extractors.helpers.generate_symbols(lib_name, sym.short_name):
yield Import(name), addr
ordinal = sym.ordinal
if ordinal != 0 and (lib_name != ""):
ordinal_name = f"#{ordinal}"
for name in capa.features.extractors.helpers.generate_symbols(lib_name, ordinal_name):
yield Import(name), addr
def extract_file_section_names(bv: BinaryView) -> Iterator[Tuple[Feature, Address]]:
"""extract section names"""
for name, section in bv.sections.items():
yield Section(name), AbsoluteVirtualAddress(section.start)
def extract_file_strings(bv: BinaryView) -> Iterator[Tuple[Feature, Address]]:
"""extract ASCII and UTF-16 LE strings"""
for s in bv.strings:
yield String(s.value), FileOffsetAddress(s.start)
def extract_file_function_names(bv: BinaryView) -> Iterator[Tuple[Feature, Address]]:
"""
extract the names of statically-linked library functions.
"""
for sym_name in bv.symbols:
for sym in bv.symbols[sym_name]:
if sym.type not in [SymbolType.LibraryFunctionSymbol, SymbolType.FunctionSymbol]:
continue
name = sym.short_name
yield FunctionName(name), sym.address
if name.startswith("_"):
# some linkers may prefix linked routines with a `_` to avoid name collisions.
# extract features for both the mangled and un-mangled representations.
# e.g. `_fwrite` -> `fwrite`
# see: https://stackoverflow.com/a/2628384/87207
yield FunctionName(name[1:]), sym.address
def extract_file_format(bv: BinaryView) -> Iterator[Tuple[Feature, Address]]:
view_type = bv.view_type
if view_type in ["PE", "COFF"]:
yield Format(FORMAT_PE), NO_ADDRESS
elif view_type == "ELF":
yield Format(FORMAT_ELF), NO_ADDRESS
elif view_type == "Raw":
# no file type to return when processing a binary file, but we want to continue processing
return
else:
raise NotImplementedError(f"unexpected file format: {view_type}")
def extract_features(bv: BinaryView) -> Iterator[Tuple[Feature, Address]]:
"""extract file features"""
for file_handler in FILE_HANDLERS:
for feature, addr in file_handler(bv):
yield feature, addr
FILE_HANDLERS = (
extract_file_export_names,
extract_file_import_names,
extract_file_strings,
extract_file_section_names,
extract_file_embedded_pe,
extract_file_function_names,
extract_file_format,
)

View File

@@ -1,35 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import subprocess
from pathlib import Path
# When the script gets executed as a standalone executable (via PyInstaller), `import binaryninja` does not work because
# we have excluded the binaryninja module in `pyinstaller.spec`. The trick here is to call the system Python and try
# to find out the path of the binaryninja module that has been installed.
# Note, including the binaryninja module in the `pyintaller.spec` would not work, since the binaryninja module tries to
# find the binaryninja core e.g., `libbinaryninjacore.dylib`, using a relative path. And this does not work when the
# binaryninja module is extracted by the PyInstaller.
code = r"""
from pathlib import Path
from importlib import util
spec = util.find_spec('binaryninja')
if spec is not None:
if len(spec.submodule_search_locations) > 0:
path = Path(spec.submodule_search_locations[0])
# encode the path with utf8 then convert to hex, make sure it can be read and restored properly
print(str(path.parent).encode('utf8').hex())
"""
def find_binja_path() -> Path:
raw_output = subprocess.check_output(["python", "-c", code]).decode("ascii").strip()
return Path(bytes.fromhex(raw_output).decode("utf8"))
if __name__ == "__main__":
print(find_binja_path())

View File

@@ -1,104 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
from typing import Tuple, Iterator
from binaryninja import Function, BinaryView, SymbolType, RegisterValueType, LowLevelILOperation
from capa.features.file import FunctionName
from capa.features.common import Feature, Characteristic
from capa.features.address import Address, AbsoluteVirtualAddress
from capa.features.extractors import loops
from capa.features.extractors.base_extractor import FunctionHandle
def extract_function_calls_to(fh: FunctionHandle):
"""extract callers to a function"""
func: Function = fh.inner
for caller in func.caller_sites:
# Everything that is a code reference to the current function is considered a caller, which actually includes
# many other references that are NOT a caller. For example, an instruction `push function_start` will also be
# considered a caller to the function
llil = caller.llil
if (llil is None) or llil.operation not in [
LowLevelILOperation.LLIL_CALL,
LowLevelILOperation.LLIL_CALL_STACK_ADJUST,
LowLevelILOperation.LLIL_JUMP,
LowLevelILOperation.LLIL_TAILCALL,
]:
continue
if llil.dest.value.type not in [
RegisterValueType.ImportedAddressValue,
RegisterValueType.ConstantValue,
RegisterValueType.ConstantPointerValue,
]:
continue
address = llil.dest.value.value
if address != func.start:
continue
yield Characteristic("calls to"), AbsoluteVirtualAddress(caller.address)
def extract_function_loop(fh: FunctionHandle):
"""extract loop indicators from a function"""
func: Function = fh.inner
edges = []
# construct control flow graph
for bb in func.basic_blocks:
for edge in bb.outgoing_edges:
edges.append((bb.start, edge.target.start))
if loops.has_loop(edges):
yield Characteristic("loop"), fh.address
def extract_recursive_call(fh: FunctionHandle):
"""extract recursive function call"""
func: Function = fh.inner
bv: BinaryView = func.view
if bv is None:
return
for ref in bv.get_code_refs(func.start):
if ref.function == func:
yield Characteristic("recursive call"), fh.address
def extract_function_name(fh: FunctionHandle):
"""extract function names (e.g., symtab names)"""
func: Function = fh.inner
bv: BinaryView = func.view
if bv is None:
return
for sym in bv.get_symbols(func.start):
if sym.type not in [SymbolType.LibraryFunctionSymbol, SymbolType.FunctionSymbol]:
continue
name = sym.short_name
yield FunctionName(name), sym.address
if name.startswith("_"):
# some linkers may prefix linked routines with a `_` to avoid name collisions.
# extract features for both the mangled and un-mangled representations.
# e.g. `_fwrite` -> `fwrite`
# see: https://stackoverflow.com/a/2628384/87207
yield FunctionName(name[1:]), sym.address
def extract_features(fh: FunctionHandle) -> Iterator[Tuple[Feature, Address]]:
for func_handler in FUNCTION_HANDLERS:
for feature, addr in func_handler(fh):
yield feature, addr
FUNCTION_HANDLERS = (extract_function_calls_to, extract_function_loop, extract_recursive_call, extract_function_name)

View File

@@ -1,60 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import logging
from typing import Tuple, Iterator
from binaryninja import BinaryView
from capa.features.common import OS, OS_MACOS, ARCH_I386, ARCH_AMD64, OS_WINDOWS, Arch, Feature
from capa.features.address import NO_ADDRESS, Address
logger = logging.getLogger(__name__)
def extract_os(bv: BinaryView) -> Iterator[Tuple[Feature, Address]]:
name = bv.platform.name
if "-" in name:
name = name.split("-")[0]
if name == "windows":
yield OS(OS_WINDOWS), NO_ADDRESS
elif name == "macos":
yield OS(OS_MACOS), NO_ADDRESS
elif name in ["linux", "freebsd", "decree"]:
yield OS(name), NO_ADDRESS
else:
# we likely end up here:
# 1. handling shellcode, or
# 2. handling a new file format (e.g. macho)
#
# for (1) we can't do much - its shellcode and all bets are off.
# we could maybe accept a further CLI argument to specify the OS,
# but i think this would be rarely used.
# rules that rely on OS conditions will fail to match on shellcode.
#
# for (2), this logic will need to be updated as the format is implemented.
logger.debug("unsupported file format: %s, will not guess OS", name)
return
def extract_arch(bv: BinaryView) -> Iterator[Tuple[Feature, Address]]:
arch = bv.arch.name
if arch == "x86_64":
yield Arch(ARCH_AMD64), NO_ADDRESS
elif arch == "x86":
yield Arch(ARCH_I386), NO_ADDRESS
else:
# we likely end up here:
# 1. handling a new architecture (e.g. aarch64)
#
# for (1), this logic will need to be updated as the format is implemented.
logger.debug("unsupported architecture: %s", arch)
return

View File

@@ -1,69 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import re
from typing import List, Callable
from dataclasses import dataclass
from binaryninja import BinaryView, LowLevelILInstruction
from binaryninja.architecture import InstructionTextToken
@dataclass
class DisassemblyInstruction:
address: int
length: int
text: List[InstructionTextToken]
LLIL_VISITOR = Callable[[LowLevelILInstruction, LowLevelILInstruction, int], bool]
def visit_llil_exprs(il: LowLevelILInstruction, func: LLIL_VISITOR):
# BN does not really support operand index at the disassembly level, so use the LLIL operand index as a substitute.
# Note, this is NOT always guaranteed to be the same as disassembly operand.
for i, op in enumerate(il.operands):
if isinstance(op, LowLevelILInstruction) and func(op, il, i):
visit_llil_exprs(op, func)
def unmangle_c_name(name: str) -> str:
# https://learn.microsoft.com/en-us/cpp/build/reference/decorated-names?view=msvc-170#FormatC
# Possible variations for BaseThreadInitThunk:
# @BaseThreadInitThunk@12
# _BaseThreadInitThunk
# _BaseThreadInitThunk@12
# It is also possible for a function to have a `Stub` appended to its name:
# _lstrlenWStub@4
# A small optimization to avoid running the regex too many times
# this still increases the unit test execution time from 170s to 200s, should be able to accelerate it
#
# TODO(xusheng): performance optimizations to improve test execution time
# https://github.com/mandiant/capa/issues/1610
if name[0] in ["@", "_"]:
match = re.match(r"^[@|_](.*?)(Stub)?(@\d+)?$", name)
if match:
return match.group(1)
return name
def read_c_string(bv: BinaryView, offset: int, max_len: int) -> str:
s: List[str] = []
while len(s) < max_len:
try:
c = bv.read(offset + len(s), 1)[0]
except Exception:
break
if c == 0:
break
s.append(chr(c))
return "".join(s)

View File

@@ -1,586 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
from typing import Any, List, Tuple, Iterator, Optional
from binaryninja import Function
from binaryninja import BasicBlock as BinjaBasicBlock
from binaryninja import (
BinaryView,
ILRegister,
SymbolType,
BinaryReader,
RegisterValueType,
LowLevelILOperation,
LowLevelILInstruction,
)
import capa.features.extractors.helpers
from capa.features.insn import API, MAX_STRUCTURE_SIZE, Number, Offset, Mnemonic, OperandNumber, OperandOffset
from capa.features.common import MAX_BYTES_FEATURE_SIZE, Bytes, String, Feature, Characteristic
from capa.features.address import Address, AbsoluteVirtualAddress
from capa.features.extractors.binja.helpers import DisassemblyInstruction, visit_llil_exprs
from capa.features.extractors.base_extractor import BBHandle, InsnHandle, FunctionHandle
# security cookie checks may perform non-zeroing XORs, these are expected within a certain
# byte range within the first and returning basic blocks, this helps to reduce FP features
SECURITY_COOKIE_BYTES_DELTA = 0x40
# check if a function is a stub function to another function/symbol. The criteria is:
# 1. The function must only have one basic block
# 2. The function must only make one call/jump to another address
# If the function being checked is a stub function, returns the target address. Otherwise, return None.
def is_stub_function(bv: BinaryView, addr: int) -> Optional[int]:
funcs = bv.get_functions_at(addr)
for func in funcs:
if len(func.basic_blocks) != 1:
continue
call_count = 0
call_target = None
for il in func.llil.instructions:
if il.operation in [
LowLevelILOperation.LLIL_CALL,
LowLevelILOperation.LLIL_CALL_STACK_ADJUST,
LowLevelILOperation.LLIL_JUMP,
LowLevelILOperation.LLIL_TAILCALL,
]:
call_count += 1
if il.dest.value.type in [
RegisterValueType.ImportedAddressValue,
RegisterValueType.ConstantValue,
RegisterValueType.ConstantPointerValue,
]:
call_target = il.dest.value.value
if call_count == 1 and call_target is not None:
return call_target
return None
def extract_insn_api_features(fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
"""
parse instruction API features
example:
call dword [0x00473038]
"""
func: Function = fh.inner
bv: BinaryView = func.view
for llil in func.get_llils_at(ih.address):
if llil.operation in [
LowLevelILOperation.LLIL_CALL,
LowLevelILOperation.LLIL_CALL_STACK_ADJUST,
LowLevelILOperation.LLIL_JUMP,
LowLevelILOperation.LLIL_TAILCALL,
]:
if llil.dest.value.type not in [
RegisterValueType.ImportedAddressValue,
RegisterValueType.ConstantValue,
RegisterValueType.ConstantPointerValue,
]:
continue
address = llil.dest.value.value
candidate_addrs = [address]
stub_addr = is_stub_function(bv, address)
if stub_addr is not None:
candidate_addrs.append(stub_addr)
for address in candidate_addrs:
for sym in func.view.get_symbols(address):
if sym is None or sym.type not in [
SymbolType.ImportAddressSymbol,
SymbolType.ImportedFunctionSymbol,
SymbolType.FunctionSymbol,
]:
continue
sym_name = sym.short_name
lib_name = ""
import_lib = bv.lookup_imported_object_library(sym.address)
if import_lib is not None:
lib_name = import_lib[0].name
if lib_name.endswith(".dll"):
lib_name = lib_name[:-4]
elif lib_name.endswith(".so"):
lib_name = lib_name[:-3]
for name in capa.features.extractors.helpers.generate_symbols(lib_name, sym_name):
yield API(name), ih.address
if sym_name.startswith("_"):
for name in capa.features.extractors.helpers.generate_symbols(lib_name, sym_name[1:]):
yield API(name), ih.address
def extract_insn_number_features(
fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
"""
parse instruction number features
example:
push 3136B0h ; dwControlCode
"""
func: Function = fh.inner
results: List[Tuple[Any[Number, OperandNumber], Address]] = []
def llil_checker(il: LowLevelILInstruction, parent: LowLevelILInstruction, index: int) -> bool:
if il.operation == LowLevelILOperation.LLIL_LOAD:
return False
if il.operation not in [LowLevelILOperation.LLIL_CONST, LowLevelILOperation.LLIL_CONST_PTR]:
return True
for op in parent.operands:
if isinstance(op, ILRegister) and op.name in ["esp", "ebp", "rsp", "rbp", "sp"]:
return False
elif isinstance(op, LowLevelILInstruction) and op.operation == LowLevelILOperation.LLIL_REG:
if op.src.name in ["esp", "ebp", "rsp", "rbp", "sp"]:
return False
raw_value = il.value.value
if parent.operation == LowLevelILOperation.LLIL_SUB:
raw_value = -raw_value
results.append((Number(raw_value), ih.address))
results.append((OperandNumber(index, raw_value), ih.address))
return False
for llil in func.get_llils_at(ih.address):
visit_llil_exprs(llil, llil_checker)
yield from results
def extract_insn_bytes_features(fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
"""
parse referenced byte sequences
example:
push offset iid_004118d4_IShellLinkA ; riid
"""
func: Function = fh.inner
bv: BinaryView = func.view
candidate_addrs = set()
llil = func.get_llil_at(ih.address)
if llil is None or llil.operation in [LowLevelILOperation.LLIL_CALL, LowLevelILOperation.LLIL_CALL_STACK_ADJUST]:
return
for ref in bv.get_code_refs_from(ih.address):
if ref == ih.address:
continue
if len(bv.get_functions_containing(ref)) > 0:
continue
candidate_addrs.add(ref)
# collect candidate address by enumerating all integers, https://github.com/Vector35/binaryninja-api/issues/3966
def llil_checker(il: LowLevelILInstruction, parent: LowLevelILInstruction, index: int) -> bool:
if il.operation in [LowLevelILOperation.LLIL_CONST, LowLevelILOperation.LLIL_CONST_PTR]:
value = il.value.value
if value > 0:
candidate_addrs.add(value)
return False
return True
for llil in func.get_llils_at(ih.address):
visit_llil_exprs(llil, llil_checker)
for addr in candidate_addrs:
extracted_bytes = bv.read(addr, MAX_BYTES_FEATURE_SIZE)
if extracted_bytes and not capa.features.extractors.helpers.all_zeros(extracted_bytes):
if bv.get_string_at(addr) is None:
# don't extract byte features for obvious strings
yield Bytes(extracted_bytes), ih.address
def extract_insn_string_features(
fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
"""
parse instruction string features
example:
push offset aAcr ; "ACR > "
"""
func: Function = fh.inner
bv: BinaryView = func.view
candidate_addrs = set()
# collect candidate address from code refs directly
for ref in bv.get_code_refs_from(ih.address):
if ref == ih.address:
continue
if len(bv.get_functions_containing(ref)) > 0:
continue
candidate_addrs.add(ref)
# collect candidate address by enumerating all integers, https://github.com/Vector35/binaryninja-api/issues/3966
def llil_checker(il: LowLevelILInstruction, parent: LowLevelILInstruction, index: int) -> bool:
if il.operation in [LowLevelILOperation.LLIL_CONST, LowLevelILOperation.LLIL_CONST_PTR]:
value = il.value.value
if value > 0:
candidate_addrs.add(value)
return False
return True
for llil in func.get_llils_at(ih.address):
visit_llil_exprs(llil, llil_checker)
# Now we have all the candidate address, check them for string or pointer to string
br = BinaryReader(bv)
for addr in candidate_addrs:
found = bv.get_string_at(addr)
if found:
yield String(found.value), ih.address
br.seek(addr)
pointer = None
if bv.arch.address_size == 4:
pointer = br.read32()
elif bv.arch.address_size == 8:
pointer = br.read64()
if pointer is not None:
found = bv.get_string_at(pointer)
if found:
yield String(found.value), ih.address
def extract_insn_offset_features(
fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
"""
parse instruction structure offset features
example:
.text:0040112F cmp [esi+4], ebx
"""
func: Function = fh.inner
results: List[Tuple[Any[Offset, OperandOffset], Address]] = []
address_size = func.view.arch.address_size * 8
def llil_checker(il: LowLevelILInstruction, parent: LowLevelILInstruction, index: int) -> bool:
# The most common case, read/write dereference to something like `dword [eax+0x28]`
if il.operation in [LowLevelILOperation.LLIL_ADD, LowLevelILOperation.LLIL_SUB]:
left = il.left
right = il.right
# Exclude offsets based on stack/franme pointers
if left.operation == LowLevelILOperation.LLIL_REG and left.src.name in ["esp", "ebp", "rsp", "rbp", "sp"]:
return True
if right.operation != LowLevelILOperation.LLIL_CONST:
return True
raw_value = right.value.value
# If this is not a dereference, then this must be an add and the offset must be in the range \
# [0, MAX_STRUCTURE_SIZE]. For example,
# add eax, 0x10,
# lea ebx, [eax + 1]
if parent.operation not in [LowLevelILOperation.LLIL_LOAD, LowLevelILOperation.LLIL_STORE]:
if il.operation != LowLevelILOperation.LLIL_ADD or (not 0 < raw_value < MAX_STRUCTURE_SIZE):
return False
if address_size > 0:
# BN also encodes the constant value as two's complement, we need to restore its original value
value = capa.features.extractors.helpers.twos_complement(raw_value, address_size)
else:
value = raw_value
results.append((Offset(value), ih.address))
results.append((OperandOffset(index, value), ih.address))
return False
# An edge case: for code like `push dword [esi]`, we need to generate a feature for offset 0x0
elif il.operation in [LowLevelILOperation.LLIL_LOAD, LowLevelILOperation.LLIL_STORE]:
if il.operands[0].operation == LowLevelILOperation.LLIL_REG:
results.append((Offset(0), ih.address))
results.append((OperandOffset(index, 0), ih.address))
return False
return True
for llil in func.get_llils_at(ih.address):
visit_llil_exprs(llil, llil_checker)
yield from results
def is_nzxor_stack_cookie(f: Function, bb: BinjaBasicBlock, llil: LowLevelILInstruction) -> bool:
"""check if nzxor exists within stack cookie delta"""
# TODO(xusheng): use LLIL SSA to do more accurate analysis
# https://github.com/mandiant/capa/issues/1609
reg_names = []
if llil.left.operation == LowLevelILOperation.LLIL_REG:
reg_names.append(llil.left.src.name)
if llil.right.operation == LowLevelILOperation.LLIL_REG:
reg_names.append(llil.right.src.name)
# stack cookie reg should be stack/frame pointer
if not any(reg in ["ebp", "esp", "rbp", "rsp", "sp"] for reg in reg_names):
return False
# expect security cookie init in first basic block within first bytes (instructions)
if len(bb.incoming_edges) == 0 and llil.address < (bb.start + SECURITY_COOKIE_BYTES_DELTA):
return True
# ... or within last bytes (instructions) before a return
if len(bb.outgoing_edges) == 0 and llil.address > (bb.end - SECURITY_COOKIE_BYTES_DELTA):
return True
return False
def extract_insn_nzxor_characteristic_features(
fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
"""
parse instruction non-zeroing XOR instruction
ignore expected non-zeroing XORs, e.g. security cookies
"""
func: Function = fh.inner
results = []
def llil_checker(il: LowLevelILInstruction, parent: LowLevelILInstruction, index: int) -> bool:
# If the two operands of the xor instruction are the same, the LLIL will be translated to other instructions,
# e.g., <llil: eax = 0>, (LLIL_SET_REG). So we do not need to check whether the two operands are the same.
if il.operation == LowLevelILOperation.LLIL_XOR:
# Exclude cases related to the stack cookie
if is_nzxor_stack_cookie(fh.inner, bbh.inner[0], il):
return False
results.append((Characteristic("nzxor"), ih.address))
return False
else:
return True
for llil in func.get_llils_at(ih.address):
visit_llil_exprs(llil, llil_checker)
yield from results
def extract_insn_mnemonic_features(
fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
"""parse instruction mnemonic features"""
insn: DisassemblyInstruction = ih.inner
yield Mnemonic(insn.text[0].text), ih.address
def extract_insn_obfs_call_plus_5_characteristic_features(
fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
"""
parse call $+5 instruction from the given instruction.
"""
insn: DisassemblyInstruction = ih.inner
if insn.text[0].text == "call" and insn.text[2].text == "$+5" and insn.length == 5:
yield Characteristic("call $+5"), ih.address
def extract_insn_peb_access_characteristic_features(
fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
"""parse instruction peb access
fs:[0x30] on x86, gs:[0x60] on x64
"""
func: Function = fh.inner
results = []
def llil_checker(il: LowLevelILInstruction, parent: LowLevelILOperation, index: int) -> bool:
if il.operation != LowLevelILOperation.LLIL_LOAD:
return True
src = il.src
if src.operation != LowLevelILOperation.LLIL_ADD:
return True
left = src.left
right = src.right
if left.operation != LowLevelILOperation.LLIL_REG:
return True
reg = left.src.name
if right.operation != LowLevelILOperation.LLIL_CONST:
return True
value = right.value.value
if (reg, value) not in (("fsbase", 0x30), ("gsbase", 0x60)):
return True
results.append((Characteristic("peb access"), ih.address))
return False
for llil in func.get_llils_at(ih.address):
visit_llil_exprs(llil, llil_checker)
yield from results
def extract_insn_segment_access_features(
fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
"""parse instruction fs or gs access"""
func: Function = fh.inner
results = []
def llil_checker(il: LowLevelILInstruction, parent: LowLevelILInstruction, index: int) -> bool:
if il.operation == LowLevelILOperation.LLIL_REG:
reg = il.src.name
if reg == "fsbase":
results.append((Characteristic("fs access"), ih.address))
return False
elif reg == "gsbase":
results.append((Characteristic("gs access"), ih.address))
return False
return False
return True
for llil in func.get_llils_at(ih.address):
visit_llil_exprs(llil, llil_checker)
yield from results
def extract_insn_cross_section_cflow(
fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
"""inspect the instruction for a CALL or JMP that crosses section boundaries"""
func: Function = fh.inner
bv: BinaryView = func.view
if bv is None:
return
seg1 = bv.get_segment_at(ih.address)
sections1 = bv.get_sections_at(ih.address)
for ref in bv.get_code_refs_from(ih.address):
if len(bv.get_functions_at(ref)) == 0:
continue
seg2 = bv.get_segment_at(ref)
sections2 = bv.get_sections_at(ref)
if seg1 != seg2 or sections1 != sections2:
yield Characteristic("cross section flow"), ih.address
def extract_function_calls_from(fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
"""extract functions calls from features
most relevant at the function scope, however, its most efficient to extract at the instruction scope
"""
func: Function = fh.inner
bv: BinaryView = func.view
if bv is None:
return
for il in func.get_llils_at(ih.address):
if il.operation not in [
LowLevelILOperation.LLIL_CALL,
LowLevelILOperation.LLIL_CALL_STACK_ADJUST,
LowLevelILOperation.LLIL_TAILCALL,
]:
continue
dest = il.dest
if dest.operation == LowLevelILOperation.LLIL_CONST_PTR:
value = dest.value.value
yield Characteristic("calls from"), AbsoluteVirtualAddress(value)
elif dest.operation == LowLevelILOperation.LLIL_CONST:
yield Characteristic("calls from"), AbsoluteVirtualAddress(dest.value)
elif dest.operation == LowLevelILOperation.LLIL_LOAD:
indirect_src = dest.src
if indirect_src.operation == LowLevelILOperation.LLIL_CONST_PTR:
value = indirect_src.value.value
yield Characteristic("calls from"), AbsoluteVirtualAddress(value)
elif indirect_src.operation == LowLevelILOperation.LLIL_CONST:
yield Characteristic("calls from"), AbsoluteVirtualAddress(indirect_src.value)
elif dest.operation == LowLevelILOperation.LLIL_REG:
if dest.value.type in [
RegisterValueType.ImportedAddressValue,
RegisterValueType.ConstantValue,
RegisterValueType.ConstantPointerValue,
]:
yield Characteristic("calls from"), AbsoluteVirtualAddress(dest.value.value)
def extract_function_indirect_call_characteristic_features(
fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
"""extract indirect function calls (e.g., call eax or call dword ptr [edx+4])
does not include calls like => call ds:dword_ABD4974
most relevant at the function or basic block scope;
however, its most efficient to extract at the instruction scope
"""
func: Function = fh.inner
llil = func.get_llil_at(ih.address)
if llil is None or llil.operation not in [
LowLevelILOperation.LLIL_CALL,
LowLevelILOperation.LLIL_CALL_STACK_ADJUST,
LowLevelILOperation.LLIL_TAILCALL,
]:
return
if llil.dest.operation in [LowLevelILOperation.LLIL_CONST, LowLevelILOperation.LLIL_CONST_PTR]:
return
if llil.dest.operation == LowLevelILOperation.LLIL_LOAD:
src = llil.dest.src
if src.operation in [LowLevelILOperation.LLIL_CONST, LowLevelILOperation.LLIL_CONST_PTR]:
return
yield Characteristic("indirect call"), ih.address
def extract_features(f: FunctionHandle, bbh: BBHandle, insn: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
"""extract instruction features"""
for inst_handler in INSTRUCTION_HANDLERS:
for feature, ea in inst_handler(f, bbh, insn):
yield feature, ea
INSTRUCTION_HANDLERS = (
extract_insn_api_features,
extract_insn_number_features,
extract_insn_bytes_features,
extract_insn_string_features,
extract_insn_offset_features,
extract_insn_nzxor_characteristic_features,
extract_insn_mnemonic_features,
extract_insn_obfs_call_plus_5_characteristic_features,
extract_insn_peb_access_characteristic_features,
extract_insn_cross_section_cflow,
extract_insn_segment_access_features,
extract_function_calls_from,
extract_function_indirect_call_characteristic_features,
)

View File

@@ -1,135 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import io
import logging
import binascii
import contextlib
from typing import Tuple, Iterator
import pefile
import capa.features
import capa.features.extractors.elf
import capa.features.extractors.pefile
import capa.features.extractors.strings
from capa.features.common import (
OS,
OS_ANY,
OS_AUTO,
ARCH_ANY,
FORMAT_PE,
FORMAT_ELF,
OS_WINDOWS,
FORMAT_FREEZE,
FORMAT_RESULT,
Arch,
Format,
String,
Feature,
)
from capa.features.freeze import is_freeze
from capa.features.address import NO_ADDRESS, Address, FileOffsetAddress
logger = logging.getLogger(__name__)
# match strings for formats
MATCH_PE = b"MZ"
MATCH_ELF = b"\x7fELF"
MATCH_RESULT = b'{"meta":'
def extract_file_strings(buf, **kwargs) -> Iterator[Tuple[String, Address]]:
"""
extract ASCII and UTF-16 LE strings from file
"""
for s in capa.features.extractors.strings.extract_ascii_strings(buf):
yield String(s.s), FileOffsetAddress(s.offset)
for s in capa.features.extractors.strings.extract_unicode_strings(buf):
yield String(s.s), FileOffsetAddress(s.offset)
def extract_format(buf) -> Iterator[Tuple[Feature, Address]]:
if buf.startswith(MATCH_PE):
yield Format(FORMAT_PE), NO_ADDRESS
elif buf.startswith(MATCH_ELF):
yield Format(FORMAT_ELF), NO_ADDRESS
elif is_freeze(buf):
yield Format(FORMAT_FREEZE), NO_ADDRESS
elif buf.startswith(MATCH_RESULT):
yield Format(FORMAT_RESULT), NO_ADDRESS
else:
# we likely end up here:
# 1. handling a file format (e.g. macho)
#
# for (1), this logic will need to be updated as the format is implemented.
logger.debug("unsupported file format: %s", binascii.hexlify(buf[:4]).decode("ascii"))
return
def extract_arch(buf) -> Iterator[Tuple[Feature, Address]]:
if buf.startswith(MATCH_PE):
yield from capa.features.extractors.pefile.extract_file_arch(pe=pefile.PE(data=buf))
elif buf.startswith(MATCH_RESULT):
yield Arch(ARCH_ANY), NO_ADDRESS
elif buf.startswith(MATCH_ELF):
with contextlib.closing(io.BytesIO(buf)) as f:
arch = capa.features.extractors.elf.detect_elf_arch(f)
if arch not in capa.features.common.VALID_ARCH:
logger.debug("unsupported arch: %s", arch)
return
yield Arch(arch), NO_ADDRESS
else:
# we likely end up here:
# 1. handling shellcode, or
# 2. handling a new file format (e.g. macho)
#
# for (1) we can't do much - its shellcode and all bets are off.
# we could maybe accept a further CLI argument to specify the arch,
# but i think this would be rarely used.
# rules that rely on arch conditions will fail to match on shellcode.
#
# for (2), this logic will need to be updated as the format is implemented.
logger.debug("unsupported file format: %s, will not guess Arch", binascii.hexlify(buf[:4]).decode("ascii"))
return
def extract_os(buf, os=OS_AUTO) -> Iterator[Tuple[Feature, Address]]:
if os != OS_AUTO:
yield OS(os), NO_ADDRESS
if buf.startswith(MATCH_PE):
yield OS(OS_WINDOWS), NO_ADDRESS
elif buf.startswith(MATCH_RESULT):
yield OS(OS_ANY), NO_ADDRESS
elif buf.startswith(MATCH_ELF):
with contextlib.closing(io.BytesIO(buf)) as f:
os = capa.features.extractors.elf.detect_elf_os(f)
if os not in capa.features.common.VALID_OS:
logger.debug("unsupported os: %s", os)
return
yield OS(os), NO_ADDRESS
else:
# we likely end up here:
# 1. handling shellcode, or
# 2. handling a new file format (e.g. macho)
#
# for (1) we can't do much - its shellcode and all bets are off.
# rules that rely on OS conditions will fail to match on shellcode.
#
# for (2), this logic will need to be updated as the format is implemented.
logger.debug("unsupported file format: %s, will not guess OS", binascii.hexlify(buf[:4]).decode("ascii"))
return

View File

@@ -1,155 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
from __future__ import annotations
from typing import Dict, List, Tuple, Union, Iterator, Optional
from pathlib import Path
import dnfile
from dncil.cil.opcode import OpCodes
import capa.features.extractors
import capa.features.extractors.dotnetfile
import capa.features.extractors.dnfile.file
import capa.features.extractors.dnfile.insn
import capa.features.extractors.dnfile.function
from capa.features.common import Feature
from capa.features.address import NO_ADDRESS, Address, DNTokenAddress, DNTokenOffsetAddress
from capa.features.extractors.dnfile.types import DnType, DnUnmanagedMethod
from capa.features.extractors.base_extractor import BBHandle, InsnHandle, FunctionHandle, FeatureExtractor
from capa.features.extractors.dnfile.helpers import (
get_dotnet_types,
get_dotnet_fields,
get_dotnet_managed_imports,
get_dotnet_managed_methods,
get_dotnet_unmanaged_imports,
get_dotnet_managed_method_bodies,
)
class DnFileFeatureExtractorCache:
def __init__(self, pe: dnfile.dnPE):
self.imports: Dict[int, Union[DnType, DnUnmanagedMethod]] = {}
self.native_imports: Dict[int, Union[DnType, DnUnmanagedMethod]] = {}
self.methods: Dict[int, Union[DnType, DnUnmanagedMethod]] = {}
self.fields: Dict[int, Union[DnType, DnUnmanagedMethod]] = {}
self.types: Dict[int, Union[DnType, DnUnmanagedMethod]] = {}
for import_ in get_dotnet_managed_imports(pe):
self.imports[import_.token] = import_
for native_import in get_dotnet_unmanaged_imports(pe):
self.native_imports[native_import.token] = native_import
for method in get_dotnet_managed_methods(pe):
self.methods[method.token] = method
for field in get_dotnet_fields(pe):
self.fields[field.token] = field
for type_ in get_dotnet_types(pe):
self.types[type_.token] = type_
def get_import(self, token: int) -> Optional[Union[DnType, DnUnmanagedMethod]]:
return self.imports.get(token)
def get_native_import(self, token: int) -> Optional[Union[DnType, DnUnmanagedMethod]]:
return self.native_imports.get(token)
def get_method(self, token: int) -> Optional[Union[DnType, DnUnmanagedMethod]]:
return self.methods.get(token)
def get_field(self, token: int) -> Optional[Union[DnType, DnUnmanagedMethod]]:
return self.fields.get(token)
def get_type(self, token: int) -> Optional[Union[DnType, DnUnmanagedMethod]]:
return self.types.get(token)
class DnfileFeatureExtractor(FeatureExtractor):
def __init__(self, path: Path):
super().__init__()
self.pe: dnfile.dnPE = dnfile.dnPE(str(path))
# pre-compute .NET token lookup tables; each .NET method has access to this cache for feature extraction
# most relevant at instruction scope
self.token_cache: DnFileFeatureExtractorCache = DnFileFeatureExtractorCache(self.pe)
# pre-compute these because we'll yield them at *every* scope.
self.global_features: List[Tuple[Feature, Address]] = []
self.global_features.extend(capa.features.extractors.dotnetfile.extract_file_format())
self.global_features.extend(capa.features.extractors.dotnetfile.extract_file_os(pe=self.pe))
self.global_features.extend(capa.features.extractors.dotnetfile.extract_file_arch(pe=self.pe))
def get_base_address(self):
return NO_ADDRESS
def extract_global_features(self):
yield from self.global_features
def extract_file_features(self):
yield from capa.features.extractors.dnfile.file.extract_features(self.pe)
def get_functions(self) -> Iterator[FunctionHandle]:
# create a method lookup table
methods: Dict[Address, FunctionHandle] = {}
for token, method in get_dotnet_managed_method_bodies(self.pe):
fh: FunctionHandle = FunctionHandle(
address=DNTokenAddress(token),
inner=method,
ctx={"pe": self.pe, "calls_from": set(), "calls_to": set(), "cache": self.token_cache},
)
# method tokens should be unique
assert fh.address not in methods.keys()
methods[fh.address] = fh
# calculate unique calls to/from each method
for fh in methods.values():
for insn in fh.inner.instructions:
if insn.opcode not in (
OpCodes.Call,
OpCodes.Callvirt,
OpCodes.Jmp,
OpCodes.Newobj,
):
continue
address: DNTokenAddress = DNTokenAddress(insn.operand.value)
# record call to destination method; note: we only consider MethodDef methods for destinations
dest: Optional[FunctionHandle] = methods.get(address)
if dest is not None:
dest.ctx["calls_to"].add(fh.address)
# record call from source method; note: we record all unique calls from a MethodDef method, not just
# those calls to other MethodDef methods e.g. calls to imported MemberRef methods
fh.ctx["calls_from"].add(address)
yield from methods.values()
def extract_function_features(self, fh) -> Iterator[Tuple[Feature, Address]]:
yield from capa.features.extractors.dnfile.function.extract_features(fh)
def get_basic_blocks(self, f) -> Iterator[BBHandle]:
# each dotnet method is considered 1 basic block
yield BBHandle(
address=f.address,
inner=f.inner,
)
def extract_basic_block_features(self, fh, bbh):
# we don't support basic block features
yield from []
def get_instructions(self, fh, bbh):
for insn in bbh.inner.instructions:
yield InsnHandle(
address=DNTokenOffsetAddress(bbh.address, insn.offset - (fh.inner.offset + fh.inner.header_size)),
inner=insn,
)
def extract_insn_features(self, fh, bbh, ih) -> Iterator[Tuple[Feature, Address]]:
yield from capa.features.extractors.dnfile.insn.extract_features(fh, bbh, ih)

View File

@@ -1,63 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
from __future__ import annotations
from typing import Tuple, Iterator
import dnfile
import capa.features.extractors.dotnetfile
from capa.features.file import Import, FunctionName
from capa.features.common import Class, Format, String, Feature, Namespace, Characteristic
from capa.features.address import Address
def extract_file_import_names(pe: dnfile.dnPE) -> Iterator[Tuple[Import, Address]]:
yield from capa.features.extractors.dotnetfile.extract_file_import_names(pe=pe)
def extract_file_format(pe: dnfile.dnPE) -> Iterator[Tuple[Format, Address]]:
yield from capa.features.extractors.dotnetfile.extract_file_format(pe=pe)
def extract_file_function_names(pe: dnfile.dnPE) -> Iterator[Tuple[FunctionName, Address]]:
yield from capa.features.extractors.dotnetfile.extract_file_function_names(pe=pe)
def extract_file_strings(pe: dnfile.dnPE) -> Iterator[Tuple[String, Address]]:
yield from capa.features.extractors.dotnetfile.extract_file_strings(pe=pe)
def extract_file_mixed_mode_characteristic_features(pe: dnfile.dnPE) -> Iterator[Tuple[Characteristic, Address]]:
yield from capa.features.extractors.dotnetfile.extract_file_mixed_mode_characteristic_features(pe=pe)
def extract_file_namespace_features(pe: dnfile.dnPE) -> Iterator[Tuple[Namespace, Address]]:
yield from capa.features.extractors.dotnetfile.extract_file_namespace_features(pe=pe)
def extract_file_class_features(pe: dnfile.dnPE) -> Iterator[Tuple[Class, Address]]:
yield from capa.features.extractors.dotnetfile.extract_file_class_features(pe=pe)
def extract_features(pe: dnfile.dnPE) -> Iterator[Tuple[Feature, Address]]:
for file_handler in FILE_HANDLERS:
for feature, address in file_handler(pe):
yield feature, address
FILE_HANDLERS = (
extract_file_import_names,
extract_file_function_names,
extract_file_strings,
extract_file_format,
extract_file_mixed_mode_characteristic_features,
extract_file_namespace_features,
extract_file_class_features,
)

View File

@@ -1,50 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
from __future__ import annotations
import logging
from typing import Tuple, Iterator
from capa.features.common import Feature, Characteristic
from capa.features.address import Address
from capa.features.extractors.base_extractor import FunctionHandle
logger = logging.getLogger(__name__)
def extract_function_calls_to(fh: FunctionHandle) -> Iterator[Tuple[Characteristic, Address]]:
"""extract callers to a function"""
for dest in fh.ctx["calls_to"]:
yield Characteristic("calls to"), dest
def extract_function_calls_from(fh: FunctionHandle) -> Iterator[Tuple[Characteristic, Address]]:
"""extract callers from a function"""
for src in fh.ctx["calls_from"]:
yield Characteristic("calls from"), src
def extract_recursive_call(fh: FunctionHandle) -> Iterator[Tuple[Characteristic, Address]]:
"""extract recursive function call"""
if fh.address in fh.ctx["calls_to"]:
yield Characteristic("recursive call"), fh.address
def extract_function_loop(fh: FunctionHandle) -> Iterator[Tuple[Characteristic, Address]]:
"""extract loop indicators from a function"""
raise NotImplementedError()
def extract_features(fh: FunctionHandle) -> Iterator[Tuple[Feature, Address]]:
for func_handler in FUNCTION_HANDLERS:
for feature, addr in func_handler(fh):
yield feature, addr
FUNCTION_HANDLERS = (extract_function_calls_to, extract_function_calls_from, extract_recursive_call)

View File

@@ -1,335 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
from __future__ import annotations
import logging
from typing import Dict, Tuple, Union, Iterator, Optional
import dnfile
from dncil.cil.body import CilMethodBody
from dncil.cil.error import MethodBodyFormatError
from dncil.clr.token import Token, StringToken, InvalidToken
from dncil.cil.body.reader import CilMethodBodyReaderBase
from capa.features.common import FeatureAccess
from capa.features.extractors.dnfile.types import DnType, DnUnmanagedMethod
logger = logging.getLogger(__name__)
class DnfileMethodBodyReader(CilMethodBodyReaderBase):
def __init__(self, pe: dnfile.dnPE, row: dnfile.mdtable.MethodDefRow):
self.pe: dnfile.dnPE = pe
self.offset: int = self.pe.get_offset_from_rva(row.Rva)
def read(self, n: int) -> bytes:
data: bytes = self.pe.get_data(self.pe.get_rva_from_offset(self.offset), n)
self.offset += n
return data
def tell(self) -> int:
return self.offset
def seek(self, offset: int) -> int:
self.offset = offset
return self.offset
def resolve_dotnet_token(pe: dnfile.dnPE, token: Token) -> Union[dnfile.base.MDTableRow, InvalidToken, str]:
"""map generic token to string or table row"""
assert pe.net is not None
assert pe.net.mdtables is not None
if isinstance(token, StringToken):
user_string: Optional[str] = read_dotnet_user_string(pe, token)
if user_string is None:
return InvalidToken(token.value)
return user_string
table: Optional[dnfile.base.ClrMetaDataTable] = pe.net.mdtables.tables.get(token.table)
if table is None:
# table index is not valid
return InvalidToken(token.value)
try:
return table.rows[token.rid - 1]
except IndexError:
# table index is valid but row index is not valid
return InvalidToken(token.value)
def read_dotnet_method_body(pe: dnfile.dnPE, row: dnfile.mdtable.MethodDefRow) -> Optional[CilMethodBody]:
"""read dotnet method body"""
try:
return CilMethodBody(DnfileMethodBodyReader(pe, row))
except MethodBodyFormatError as e:
logger.debug("failed to parse managed method body @ 0x%08x (%s)", row.Rva, e)
return None
def read_dotnet_user_string(pe: dnfile.dnPE, token: StringToken) -> Optional[str]:
"""read user string from #US stream"""
assert pe.net is not None
if pe.net.user_strings is None:
# stream may not exist (seen in obfuscated .NET)
logger.debug("#US stream does not exist for stream index 0x%08x", token.rid)
return None
try:
user_string: Optional[dnfile.stream.UserString] = pe.net.user_strings.get_us(token.rid)
except UnicodeDecodeError as e:
logger.debug("failed to decode #US stream index 0x%08x (%s)", token.rid, e)
return None
if user_string is None:
return None
return user_string.value
def get_dotnet_managed_imports(pe: dnfile.dnPE) -> Iterator[DnType]:
"""get managed imports from MemberRef table
see https://www.ntcore.com/files/dotnetformat.htm
10 - MemberRef Table
Each row represents an imported method
Class (index into the TypeRef, ModuleRef, MethodDef, TypeSpec or TypeDef tables)
Name (index into String heap)
01 - TypeRef Table
Each row represents an imported class, its namespace and the assembly which contains it
TypeName (index into String heap)
TypeNamespace (index into String heap)
"""
for rid, member_ref in iter_dotnet_table(pe, dnfile.mdtable.MemberRef.number):
assert isinstance(member_ref, dnfile.mdtable.MemberRefRow)
if not isinstance(member_ref.Class.row, dnfile.mdtable.TypeRefRow):
# only process class imports from TypeRef table
continue
token: int = calculate_dotnet_token_value(dnfile.mdtable.MemberRef.number, rid)
access: Optional[str]
# assume .NET imports starting with get_/set_ are used to access a property
if member_ref.Name.startswith("get_"):
access = FeatureAccess.READ
elif member_ref.Name.startswith("set_"):
access = FeatureAccess.WRITE
else:
access = None
member_ref_name: str = member_ref.Name
if member_ref_name.startswith(("get_", "set_")):
# remove get_/set_ from MemberRef name
member_ref_name = member_ref_name[4:]
yield DnType(
token,
member_ref.Class.row.TypeName,
namespace=member_ref.Class.row.TypeNamespace,
member=member_ref_name,
access=access,
)
def get_dotnet_methoddef_property_accessors(pe: dnfile.dnPE) -> Iterator[Tuple[int, str]]:
"""get MethodDef methods used to access properties
see https://www.ntcore.com/files/dotnetformat.htm
24 - MethodSemantics Table
Links Events and Properties to specific methods. For example one Event can be associated to more methods. A property uses this table to associate get/set methods.
Semantics (a 2-byte bitmask of type MethodSemanticsAttributes)
Method (index into the MethodDef table)
Association (index into the Event or Property table; more precisely, a HasSemantics coded index)
"""
for rid, method_semantics in iter_dotnet_table(pe, dnfile.mdtable.MethodSemantics.number):
assert isinstance(method_semantics, dnfile.mdtable.MethodSemanticsRow)
if method_semantics.Association.row is None:
logger.debug("MethodSemantics[0x%X] Association row is None", rid)
continue
if isinstance(method_semantics.Association.row, dnfile.mdtable.EventRow):
# ignore events
logger.debug("MethodSemantics[0x%X] ignoring Event", rid)
continue
if method_semantics.Method.table is None:
logger.debug("MethodSemantics[0x%X] Method table is None", rid)
continue
token: int = calculate_dotnet_token_value(
method_semantics.Method.table.number, method_semantics.Method.row_index
)
if method_semantics.Semantics.msSetter:
yield token, FeatureAccess.WRITE
elif method_semantics.Semantics.msGetter:
yield token, FeatureAccess.READ
def get_dotnet_managed_methods(pe: dnfile.dnPE) -> Iterator[DnType]:
"""get managed method names from TypeDef table
see https://www.ntcore.com/files/dotnetformat.htm
02 - TypeDef Table
Each row represents a class in the current assembly.
TypeName (index into String heap)
TypeNamespace (index into String heap)
MethodList (index into MethodDef table; it marks the first of a contiguous run of Methods owned by this Type)
"""
accessor_map: Dict[int, str] = {}
for methoddef, methoddef_access in get_dotnet_methoddef_property_accessors(pe):
accessor_map[methoddef] = methoddef_access
for rid, typedef in iter_dotnet_table(pe, dnfile.mdtable.TypeDef.number):
assert isinstance(typedef, dnfile.mdtable.TypeDefRow)
for idx, method in enumerate(typedef.MethodList):
if method.table is None:
logger.debug("TypeDef[0x%X] MethodList[0x%X] table is None", rid, idx)
continue
if method.row is None:
logger.debug("TypeDef[0x%X] MethodList[0x%X] row is None", rid, idx)
continue
token: int = calculate_dotnet_token_value(method.table.number, method.row_index)
access: Optional[str] = accessor_map.get(token)
method_name: str = method.row.Name
if method_name.startswith(("get_", "set_")):
# remove get_/set_
method_name = method_name[4:]
yield DnType(token, typedef.TypeName, namespace=typedef.TypeNamespace, member=method_name, access=access)
def get_dotnet_fields(pe: dnfile.dnPE) -> Iterator[DnType]:
"""get fields from TypeDef table
see https://www.ntcore.com/files/dotnetformat.htm
02 - TypeDef Table
Each row represents a class in the current assembly.
TypeName (index into String heap)
TypeNamespace (index into String heap)
FieldList (index into Field table; it marks the first of a contiguous run of Fields owned by this Type)
"""
for rid, typedef in iter_dotnet_table(pe, dnfile.mdtable.TypeDef.number):
assert isinstance(typedef, dnfile.mdtable.TypeDefRow)
for idx, field in enumerate(typedef.FieldList):
if field.table is None:
logger.debug("TypeDef[0x%X] FieldList[0x%X] table is None", rid, idx)
continue
if field.row is None:
logger.debug("TypeDef[0x%X] FieldList[0x%X] row is None", rid, idx)
continue
token: int = calculate_dotnet_token_value(field.table.number, field.row_index)
yield DnType(token, typedef.TypeName, namespace=typedef.TypeNamespace, member=field.row.Name)
def get_dotnet_managed_method_bodies(pe: dnfile.dnPE) -> Iterator[Tuple[int, CilMethodBody]]:
"""get managed methods from MethodDef table"""
for rid, method_def in iter_dotnet_table(pe, dnfile.mdtable.MethodDef.number):
assert isinstance(method_def, dnfile.mdtable.MethodDefRow)
if not method_def.ImplFlags.miIL or any((method_def.Flags.mdAbstract, method_def.Flags.mdPinvokeImpl)):
# skip methods that do not have a method body
continue
body: Optional[CilMethodBody] = read_dotnet_method_body(pe, method_def)
if body is None:
logger.debug("MethodDef[0x%X] method body is None", rid)
continue
token: int = calculate_dotnet_token_value(dnfile.mdtable.MethodDef.number, rid)
yield token, body
def get_dotnet_unmanaged_imports(pe: dnfile.dnPE) -> Iterator[DnUnmanagedMethod]:
"""get unmanaged imports from ImplMap table
see https://www.ntcore.com/files/dotnetformat.htm
28 - ImplMap Table
ImplMap table holds information about unmanaged methods that can be reached from managed code, using PInvoke dispatch
MemberForwarded (index into the Field or MethodDef table; more precisely, a MemberForwarded coded index)
ImportName (index into the String heap)
ImportScope (index into the ModuleRef table)
"""
for rid, impl_map in iter_dotnet_table(pe, dnfile.mdtable.ImplMap.number):
assert isinstance(impl_map, dnfile.mdtable.ImplMapRow)
module: str
if impl_map.ImportScope.row is None:
logger.debug("ImplMap[0x%X] ImportScope row is None", rid)
module = ""
else:
module = impl_map.ImportScope.row.Name
method: str = impl_map.ImportName
member_forward_table: int
if impl_map.MemberForwarded.table is None:
logger.debug("ImplMap[0x%X] MemberForwarded table is None", rid)
continue
else:
member_forward_table = impl_map.MemberForwarded.table.number
member_forward_row: int = impl_map.MemberForwarded.row_index
# ECMA says "Each row of the ImplMap table associates a row in the MethodDef table (MemberForwarded) with the
# name of a routine (ImportName) in some unmanaged DLL (ImportScope)"; so we calculate and map the MemberForwarded
# MethodDef table token to help us later record native import method calls made from CIL
token: int = calculate_dotnet_token_value(member_forward_table, member_forward_row)
# like Kernel32.dll
if module and "." in module:
module = module.split(".")[0]
# like kernel32.CreateFileA
yield DnUnmanagedMethod(token, module, method)
def get_dotnet_types(pe: dnfile.dnPE) -> Iterator[DnType]:
"""get .NET types from TypeDef and TypeRef tables"""
for rid, typedef in iter_dotnet_table(pe, dnfile.mdtable.TypeDef.number):
assert isinstance(typedef, dnfile.mdtable.TypeDefRow)
typedef_token: int = calculate_dotnet_token_value(dnfile.mdtable.TypeDef.number, rid)
yield DnType(typedef_token, typedef.TypeName, namespace=typedef.TypeNamespace)
for rid, typeref in iter_dotnet_table(pe, dnfile.mdtable.TypeRef.number):
assert isinstance(typeref, dnfile.mdtable.TypeRefRow)
typeref_token: int = calculate_dotnet_token_value(dnfile.mdtable.TypeRef.number, rid)
yield DnType(typeref_token, typeref.TypeName, namespace=typeref.TypeNamespace)
def calculate_dotnet_token_value(table: int, rid: int) -> int:
return ((table & 0xFF) << Token.TABLE_SHIFT) | (rid & Token.RID_MASK)
def is_dotnet_mixed_mode(pe: dnfile.dnPE) -> bool:
assert pe.net is not None
assert pe.net.Flags is not None
return not bool(pe.net.Flags.CLR_ILONLY)
def iter_dotnet_table(pe: dnfile.dnPE, table_index: int) -> Iterator[Tuple[int, dnfile.base.MDTableRow]]:
assert pe.net is not None
assert pe.net.mdtables is not None
for rid, row in enumerate(pe.net.mdtables.tables.get(table_index, [])):
# .NET tables are 1-indexed
yield rid + 1, row

View File

@@ -1,227 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
from __future__ import annotations
import logging
from typing import TYPE_CHECKING, Tuple, Union, Iterator, Optional
if TYPE_CHECKING:
from capa.features.extractors.dnfile.extractor import DnFileFeatureExtractorCache
import dnfile
from dncil.clr.token import Token, StringToken, InvalidToken
from dncil.cil.opcode import OpCodes
import capa.features.extractors.helpers
from capa.features.insn import API, Number, Property
from capa.features.common import Class, String, Feature, Namespace, FeatureAccess, Characteristic
from capa.features.address import Address
from capa.features.extractors.dnfile.types import DnType, DnUnmanagedMethod
from capa.features.extractors.base_extractor import BBHandle, InsnHandle, FunctionHandle
from capa.features.extractors.dnfile.helpers import (
resolve_dotnet_token,
read_dotnet_user_string,
calculate_dotnet_token_value,
)
logger = logging.getLogger(__name__)
def get_callee(
pe: dnfile.dnPE, cache: DnFileFeatureExtractorCache, token: Token
) -> Optional[Union[DnType, DnUnmanagedMethod]]:
"""map .NET token to un/managed (generic) method"""
token_: int
if token.table == dnfile.mdtable.MethodSpec.number:
# map MethodSpec to MethodDef or MemberRef
row: Union[dnfile.base.MDTableRow, InvalidToken, str] = resolve_dotnet_token(pe, token)
assert isinstance(row, dnfile.mdtable.MethodSpecRow)
if row.Method.table is None:
logger.debug("MethodSpec[0x%X] Method table is None", token.rid)
return None
token_ = calculate_dotnet_token_value(row.Method.table.number, row.Method.row_index)
else:
token_ = token.value
callee: Optional[Union[DnType, DnUnmanagedMethod]] = cache.get_import(token_)
if callee is None:
# we must check unmanaged imports before managed methods because we map forwarded managed methods
# to their unmanaged imports; we prefer a forwarded managed method be mapped to its unmanaged import for analysis
callee = cache.get_native_import(token_)
if callee is None:
callee = cache.get_method(token_)
return callee
def extract_insn_api_features(fh: FunctionHandle, bh, ih: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
"""parse instruction API features"""
if ih.inner.opcode not in (
OpCodes.Call,
OpCodes.Callvirt,
OpCodes.Jmp,
OpCodes.Newobj,
):
return
callee: Optional[Union[DnType, DnUnmanagedMethod]] = get_callee(fh.ctx["pe"], fh.ctx["cache"], ih.inner.operand)
if isinstance(callee, DnType):
# ignore methods used to access properties
if callee.access is None:
# like System.IO.File::Delete
yield API(str(callee)), ih.address
elif isinstance(callee, DnUnmanagedMethod):
# like kernel32.CreateFileA
for name in capa.features.extractors.helpers.generate_symbols(callee.module, callee.method):
yield API(name), ih.address
def extract_insn_property_features(fh: FunctionHandle, bh, ih: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
"""parse instruction property features"""
name: Optional[str] = None
access: Optional[str] = None
if ih.inner.opcode in (OpCodes.Call, OpCodes.Callvirt, OpCodes.Jmp):
# property access via MethodDef or MemberRef
callee: Optional[Union[DnType, DnUnmanagedMethod]] = get_callee(fh.ctx["pe"], fh.ctx["cache"], ih.inner.operand)
if isinstance(callee, DnType):
if callee.access is not None:
name = str(callee)
access = callee.access
elif ih.inner.opcode in (OpCodes.Ldfld, OpCodes.Ldflda, OpCodes.Ldsfld, OpCodes.Ldsflda):
# property read via Field
read_field: Optional[Union[DnType, DnUnmanagedMethod]] = fh.ctx["cache"].get_field(ih.inner.operand.value)
if read_field is not None:
name = str(read_field)
access = FeatureAccess.READ
elif ih.inner.opcode in (OpCodes.Stfld, OpCodes.Stsfld):
# property write via Field
write_field: Optional[Union[DnType, DnUnmanagedMethod]] = fh.ctx["cache"].get_field(ih.inner.operand.value)
if write_field is not None:
name = str(write_field)
access = FeatureAccess.WRITE
if name is not None:
if access is not None:
yield Property(name, access=access), ih.address
yield Property(name), ih.address
def extract_insn_namespace_class_features(
fh: FunctionHandle, bh, ih: InsnHandle
) -> Iterator[Tuple[Union[Namespace, Class], Address]]:
"""parse instruction namespace and class features"""
type_: Optional[Union[DnType, DnUnmanagedMethod]] = None
if ih.inner.opcode in (
OpCodes.Call,
OpCodes.Callvirt,
OpCodes.Jmp,
OpCodes.Ldvirtftn,
OpCodes.Ldftn,
OpCodes.Newobj,
):
# method call - includes managed methods (MethodDef, TypeRef) and properties (MethodSemantics, TypeRef)
type_ = get_callee(fh.ctx["pe"], fh.ctx["cache"], ih.inner.operand)
elif ih.inner.opcode in (
OpCodes.Ldfld,
OpCodes.Ldflda,
OpCodes.Ldsfld,
OpCodes.Ldsflda,
OpCodes.Stfld,
OpCodes.Stsfld,
):
# field access
type_ = fh.ctx["cache"].get_field(ih.inner.operand.value)
# ECMA 335 VI.C.4.10
elif ih.inner.opcode in (
OpCodes.Initobj,
OpCodes.Box,
OpCodes.Castclass,
OpCodes.Cpobj,
OpCodes.Isinst,
OpCodes.Ldelem,
OpCodes.Ldelema,
OpCodes.Ldobj,
OpCodes.Mkrefany,
OpCodes.Newarr,
OpCodes.Refanyval,
OpCodes.Sizeof,
OpCodes.Stobj,
OpCodes.Unbox,
OpCodes.Constrained,
OpCodes.Stelem,
OpCodes.Unbox_Any,
):
# type access
type_ = fh.ctx["cache"].get_type(ih.inner.operand.value)
if isinstance(type_, DnType):
yield Class(DnType.format_name(type_.class_, namespace=type_.namespace)), ih.address
if type_.namespace:
yield Namespace(type_.namespace), ih.address
def extract_insn_number_features(fh, bh, ih: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
"""parse instruction number features"""
if ih.inner.is_ldc():
yield Number(ih.inner.get_ldc()), ih.address
def extract_insn_string_features(fh: FunctionHandle, bh, ih: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
"""parse instruction string features"""
if not ih.inner.is_ldstr():
return
if not isinstance(ih.inner.operand, StringToken):
return
user_string: Optional[str] = read_dotnet_user_string(fh.ctx["pe"], ih.inner.operand)
if user_string is None:
return
if len(user_string) >= 4:
yield String(user_string), ih.address
def extract_unmanaged_call_characteristic_features(
fh: FunctionHandle, bb: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Characteristic, Address]]:
if ih.inner.opcode not in (OpCodes.Call, OpCodes.Callvirt, OpCodes.Jmp):
return
row: Union[str, InvalidToken, dnfile.base.MDTableRow] = resolve_dotnet_token(fh.ctx["pe"], ih.inner.operand)
if not isinstance(row, dnfile.mdtable.MethodDefRow):
return
if any((row.Flags.mdPinvokeImpl, row.ImplFlags.miUnmanaged, row.ImplFlags.miNative)):
yield Characteristic("unmanaged call"), ih.address
def extract_features(fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
"""extract instruction features"""
for inst_handler in INSTRUCTION_HANDLERS:
for feature, addr in inst_handler(fh, bbh, ih):
assert isinstance(addr, Address)
yield feature, addr
INSTRUCTION_HANDLERS = (
extract_insn_api_features,
extract_insn_property_features,
extract_insn_number_features,
extract_insn_string_features,
extract_insn_namespace_class_features,
extract_unmanaged_call_characteristic_features,
)

View File

@@ -1,74 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
from typing import Optional
class DnType:
def __init__(self, token: int, class_: str, namespace: str = "", member: str = "", access: Optional[str] = None):
self.token: int = token
self.access: Optional[str] = access
self.namespace: str = namespace
self.class_: str = class_
if member == ".ctor":
member = "ctor"
if member == ".cctor":
member = "cctor"
self.member: str = member
def __hash__(self):
return hash((self.token, self.access, self.namespace, self.class_, self.member))
def __eq__(self, other):
return (
self.token == other.token
and self.access == other.access
and self.namespace == other.namespace
and self.class_ == other.class_
and self.member == other.member
)
def __str__(self):
return DnType.format_name(self.class_, namespace=self.namespace, member=self.member)
def __repr__(self):
return str(self)
@staticmethod
def format_name(class_: str, namespace: str = "", member: str = ""):
# like File::OpenRead
name: str = f"{class_}::{member}" if member else class_
if namespace:
# like System.IO.File::OpenRead
name = f"{namespace}.{name}"
return name
class DnUnmanagedMethod:
def __init__(self, token: int, module: str, method: str):
self.token: int = token
self.module: str = module
self.method: str = method
def __hash__(self):
return hash((self.token, self.module, self.method))
def __eq__(self, other):
return self.token == other.token and self.module == other.module and self.method == other.method
def __str__(self):
return DnUnmanagedMethod.format_name(self.module, self.method)
def __repr__(self):
return str(self)
@staticmethod
def format_name(module, method):
return f"{module}.{method}"

View File

@@ -1,158 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import logging
from typing import Tuple, Iterator
from pathlib import Path
import dnfile
import pefile
from capa.features.common import (
OS,
OS_ANY,
ARCH_ANY,
ARCH_I386,
FORMAT_PE,
ARCH_AMD64,
FORMAT_DOTNET,
Arch,
Format,
Feature,
)
from capa.features.address import NO_ADDRESS, Address, AbsoluteVirtualAddress
from capa.features.extractors.base_extractor import FeatureExtractor
logger = logging.getLogger(__name__)
def extract_file_format(**kwargs) -> Iterator[Tuple[Feature, Address]]:
yield Format(FORMAT_PE), NO_ADDRESS
yield Format(FORMAT_DOTNET), NO_ADDRESS
def extract_file_os(**kwargs) -> Iterator[Tuple[Feature, Address]]:
yield OS(OS_ANY), NO_ADDRESS
def extract_file_arch(pe: dnfile.dnPE, **kwargs) -> Iterator[Tuple[Feature, Address]]:
# to distinguish in more detail, see https://stackoverflow.com/a/23614024/10548020
# .NET 4.5 added option: any CPU, 32-bit preferred
assert pe.net is not None
assert pe.net.Flags is not None
if pe.net.Flags.CLR_32BITREQUIRED and pe.PE_TYPE == pefile.OPTIONAL_HEADER_MAGIC_PE:
yield Arch(ARCH_I386), NO_ADDRESS
elif not pe.net.Flags.CLR_32BITREQUIRED and pe.PE_TYPE == pefile.OPTIONAL_HEADER_MAGIC_PE_PLUS:
yield Arch(ARCH_AMD64), NO_ADDRESS
else:
yield Arch(ARCH_ANY), NO_ADDRESS
def extract_file_features(pe: dnfile.dnPE) -> Iterator[Tuple[Feature, Address]]:
for file_handler in FILE_HANDLERS:
for feature, address in file_handler(pe=pe): # type: ignore
yield feature, address
FILE_HANDLERS = (
# extract_file_export_names,
# extract_file_import_names,
# extract_file_section_names,
# extract_file_strings,
# extract_file_function_names,
extract_file_format,
)
def extract_global_features(pe: dnfile.dnPE) -> Iterator[Tuple[Feature, Address]]:
for handler in GLOBAL_HANDLERS:
for feature, addr in handler(pe=pe): # type: ignore
yield feature, addr
GLOBAL_HANDLERS = (
extract_file_os,
extract_file_arch,
)
class DnfileFeatureExtractor(FeatureExtractor):
def __init__(self, path: Path):
super().__init__()
self.path: Path = path
self.pe: dnfile.dnPE = dnfile.dnPE(str(path))
def get_base_address(self) -> AbsoluteVirtualAddress:
return AbsoluteVirtualAddress(0x0)
def get_entry_point(self) -> int:
# self.pe.net.Flags.CLT_NATIVE_ENTRYPOINT
# True: native EP: Token
# False: managed EP: RVA
assert self.pe.net is not None
assert self.pe.net.struct is not None
return self.pe.net.struct.EntryPointTokenOrRva
def extract_global_features(self):
yield from extract_global_features(self.pe)
def extract_file_features(self):
yield from extract_file_features(self.pe)
def is_dotnet_file(self) -> bool:
return bool(self.pe.net)
def is_mixed_mode(self) -> bool:
assert self.pe is not None
assert self.pe.net is not None
assert self.pe.net.Flags is not None
return not bool(self.pe.net.Flags.CLR_ILONLY)
def get_runtime_version(self) -> Tuple[int, int]:
assert self.pe is not None
assert self.pe.net is not None
assert self.pe.net.struct is not None
return self.pe.net.struct.MajorRuntimeVersion, self.pe.net.struct.MinorRuntimeVersion
def get_meta_version_string(self) -> str:
assert self.pe.net is not None
assert self.pe.net.metadata is not None
assert self.pe.net.metadata.struct is not None
assert self.pe.net.metadata.struct.Version is not None
vbuf = self.pe.net.metadata.struct.Version
assert isinstance(vbuf, bytes)
return vbuf.rstrip(b"\x00").decode("utf-8")
def get_functions(self):
raise NotImplementedError("DnfileFeatureExtractor can only be used to extract file features")
def extract_function_features(self, f):
raise NotImplementedError("DnfileFeatureExtractor can only be used to extract file features")
def get_basic_blocks(self, f):
raise NotImplementedError("DnfileFeatureExtractor can only be used to extract file features")
def extract_basic_block_features(self, f, bb):
raise NotImplementedError("DnfileFeatureExtractor can only be used to extract file features")
def get_instructions(self, f, bb):
raise NotImplementedError("DnfileFeatureExtractor can only be used to extract file features")
def extract_insn_features(self, f, bb, insn):
raise NotImplementedError("DnfileFeatureExtractor can only be used to extract file features")
def is_library_function(self, va):
raise NotImplementedError("DnfileFeatureExtractor can only be used to extract file features")
def get_function_name(self, va):
raise NotImplementedError("DnfileFeatureExtractor can only be used to extract file features")

View File

@@ -1,239 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import logging
from typing import Tuple, Iterator
from pathlib import Path
import dnfile
import pefile
import capa.features.extractors.helpers
from capa.features.file import Import, FunctionName
from capa.features.common import (
OS,
OS_ANY,
ARCH_ANY,
ARCH_I386,
FORMAT_PE,
ARCH_AMD64,
FORMAT_DOTNET,
Arch,
Class,
Format,
String,
Feature,
Namespace,
Characteristic,
)
from capa.features.address import NO_ADDRESS, Address, DNTokenAddress
from capa.features.extractors.base_extractor import FeatureExtractor
from capa.features.extractors.dnfile.helpers import (
DnType,
iter_dotnet_table,
is_dotnet_mixed_mode,
get_dotnet_managed_imports,
get_dotnet_managed_methods,
calculate_dotnet_token_value,
get_dotnet_unmanaged_imports,
)
logger = logging.getLogger(__name__)
def extract_file_format(**kwargs) -> Iterator[Tuple[Format, Address]]:
yield Format(FORMAT_PE), NO_ADDRESS
yield Format(FORMAT_DOTNET), NO_ADDRESS
def extract_file_import_names(pe: dnfile.dnPE, **kwargs) -> Iterator[Tuple[Import, Address]]:
for method in get_dotnet_managed_imports(pe):
# like System.IO.File::OpenRead
yield Import(str(method)), DNTokenAddress(method.token)
for imp in get_dotnet_unmanaged_imports(pe):
# like kernel32.CreateFileA
for name in capa.features.extractors.helpers.generate_symbols(imp.module, imp.method):
yield Import(name), DNTokenAddress(imp.token)
def extract_file_function_names(pe: dnfile.dnPE, **kwargs) -> Iterator[Tuple[FunctionName, Address]]:
for method in get_dotnet_managed_methods(pe):
yield FunctionName(str(method)), DNTokenAddress(method.token)
def extract_file_namespace_features(pe: dnfile.dnPE, **kwargs) -> Iterator[Tuple[Namespace, Address]]:
"""emit namespace features from TypeRef and TypeDef tables"""
# namespaces may be referenced multiple times, so we need to filter
namespaces = set()
for _, typedef in iter_dotnet_table(pe, dnfile.mdtable.TypeDef.number):
# emit internal .NET namespaces
assert isinstance(typedef, dnfile.mdtable.TypeDefRow)
namespaces.add(typedef.TypeNamespace)
for _, typeref in iter_dotnet_table(pe, dnfile.mdtable.TypeRef.number):
# emit external .NET namespaces
assert isinstance(typeref, dnfile.mdtable.TypeRefRow)
namespaces.add(typeref.TypeNamespace)
# namespaces may be empty, discard
namespaces.discard("")
for namespace in namespaces:
# namespace do not have an associated token, so we yield 0x0
yield Namespace(namespace), NO_ADDRESS
def extract_file_class_features(pe: dnfile.dnPE, **kwargs) -> Iterator[Tuple[Class, Address]]:
"""emit class features from TypeRef and TypeDef tables"""
for rid, typedef in iter_dotnet_table(pe, dnfile.mdtable.TypeDef.number):
# emit internal .NET classes
assert isinstance(typedef, dnfile.mdtable.TypeDefRow)
token = calculate_dotnet_token_value(dnfile.mdtable.TypeDef.number, rid)
yield Class(DnType.format_name(typedef.TypeName, namespace=typedef.TypeNamespace)), DNTokenAddress(token)
for rid, typeref in iter_dotnet_table(pe, dnfile.mdtable.TypeRef.number):
# emit external .NET classes
assert isinstance(typeref, dnfile.mdtable.TypeRefRow)
token = calculate_dotnet_token_value(dnfile.mdtable.TypeRef.number, rid)
yield Class(DnType.format_name(typeref.TypeName, namespace=typeref.TypeNamespace)), DNTokenAddress(token)
def extract_file_os(**kwargs) -> Iterator[Tuple[OS, Address]]:
yield OS(OS_ANY), NO_ADDRESS
def extract_file_arch(pe: dnfile.dnPE, **kwargs) -> Iterator[Tuple[Arch, Address]]:
# to distinguish in more detail, see https://stackoverflow.com/a/23614024/10548020
# .NET 4.5 added option: any CPU, 32-bit preferred
assert pe.net is not None
assert pe.net.Flags is not None
if pe.net.Flags.CLR_32BITREQUIRED and pe.PE_TYPE == pefile.OPTIONAL_HEADER_MAGIC_PE:
yield Arch(ARCH_I386), NO_ADDRESS
elif not pe.net.Flags.CLR_32BITREQUIRED and pe.PE_TYPE == pefile.OPTIONAL_HEADER_MAGIC_PE_PLUS:
yield Arch(ARCH_AMD64), NO_ADDRESS
else:
yield Arch(ARCH_ANY), NO_ADDRESS
def extract_file_strings(pe: dnfile.dnPE, **kwargs) -> Iterator[Tuple[String, Address]]:
yield from capa.features.extractors.common.extract_file_strings(pe.__data__)
def extract_file_mixed_mode_characteristic_features(
pe: dnfile.dnPE, **kwargs
) -> Iterator[Tuple[Characteristic, Address]]:
if is_dotnet_mixed_mode(pe):
yield Characteristic("mixed mode"), NO_ADDRESS
def extract_file_features(pe: dnfile.dnPE) -> Iterator[Tuple[Feature, Address]]:
for file_handler in FILE_HANDLERS:
for feature, addr in file_handler(pe=pe): # type: ignore
yield feature, addr
FILE_HANDLERS = (
extract_file_import_names,
extract_file_function_names,
extract_file_strings,
extract_file_format,
extract_file_mixed_mode_characteristic_features,
extract_file_namespace_features,
extract_file_class_features,
)
def extract_global_features(pe: dnfile.dnPE) -> Iterator[Tuple[Feature, Address]]:
for handler in GLOBAL_HANDLERS:
for feature, va in handler(pe=pe): # type: ignore
yield feature, va
GLOBAL_HANDLERS = (
extract_file_os,
extract_file_arch,
)
class DotnetFileFeatureExtractor(FeatureExtractor):
def __init__(self, path: Path):
super().__init__()
self.path: Path = path
self.pe: dnfile.dnPE = dnfile.dnPE(str(path))
def get_base_address(self):
return NO_ADDRESS
def get_entry_point(self) -> int:
# self.pe.net.Flags.CLT_NATIVE_ENTRYPOINT
# True: native EP: Token
# False: managed EP: RVA
assert self.pe.net is not None
assert self.pe.net.struct is not None
return self.pe.net.struct.EntryPointTokenOrRva
def extract_global_features(self):
yield from extract_global_features(self.pe)
def extract_file_features(self):
yield from extract_file_features(self.pe)
def is_dotnet_file(self) -> bool:
return bool(self.pe.net)
def is_mixed_mode(self) -> bool:
return is_dotnet_mixed_mode(self.pe)
def get_runtime_version(self) -> Tuple[int, int]:
assert self.pe.net is not None
assert self.pe.net.struct is not None
assert self.pe.net.struct.MajorRuntimeVersion is not None
assert self.pe.net.struct.MinorRuntimeVersion is not None
return self.pe.net.struct.MajorRuntimeVersion, self.pe.net.struct.MinorRuntimeVersion
def get_meta_version_string(self) -> str:
assert self.pe.net is not None
assert self.pe.net.metadata is not None
assert self.pe.net.metadata.struct is not None
assert self.pe.net.metadata.struct.Version is not None
vbuf = self.pe.net.metadata.struct.Version
assert isinstance(vbuf, bytes)
return vbuf.rstrip(b"\x00").decode("utf-8")
def get_functions(self):
raise NotImplementedError("DotnetFileFeatureExtractor can only be used to extract file features")
def extract_function_features(self, f):
raise NotImplementedError("DotnetFileFeatureExtractor can only be used to extract file features")
def get_basic_blocks(self, f):
raise NotImplementedError("DotnetFileFeatureExtractor can only be used to extract file features")
def extract_basic_block_features(self, f, bb):
raise NotImplementedError("DotnetFileFeatureExtractor can only be used to extract file features")
def get_instructions(self, f, bb):
raise NotImplementedError("DotnetFileFeatureExtractor can only be used to extract file features")
def extract_insn_features(self, f, bb, insn):
raise NotImplementedError("DotnetFileFeatureExtractor can only be used to extract file features")
def is_library_function(self, va):
raise NotImplementedError("DotnetFileFeatureExtractor can only be used to extract file features")
def get_function_name(self, va):
raise NotImplementedError("DotnetFileFeatureExtractor can only be used to extract file features")

View File

@@ -1,985 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import struct
import logging
import itertools
import collections
from enum import Enum
from typing import Set, Dict, List, Tuple, BinaryIO, Iterator, Optional
from dataclasses import dataclass
import Elf # from vivisect
logger = logging.getLogger(__name__)
def align(v, alignment):
remainder = v % alignment
if remainder == 0:
return v
else:
return v + (alignment - remainder)
def read_cstr(buf, offset) -> str:
s = buf[offset:]
s, _, _ = s.partition(b"\x00")
return s.decode("utf-8")
class CorruptElfFile(ValueError):
pass
class OS(str, Enum):
HPUX = "hpux"
NETBSD = "netbsd"
LINUX = "linux"
HURD = "hurd"
_86OPEN = "86open"
SOLARIS = "solaris"
AIX = "aix"
IRIX = "irix"
FREEBSD = "freebsd"
TRU64 = "tru64"
MODESTO = "modesto"
OPENBSD = "openbsd"
OPENVMS = "openvms"
NSK = "nsk"
AROS = "aros"
FENIXOS = "fenixos"
CLOUD = "cloud"
SYLLABLE = "syllable"
NACL = "nacl"
ANDROID = "android"
# via readelf: https://github.com/bminor/binutils-gdb/blob/c0e94211e1ac05049a4ce7c192c9d14d1764eb3e/binutils/readelf.c#L19635-L19658
# and here: https://github.com/bminor/binutils-gdb/blob/34c54daa337da9fadf87d2706d6a590ae1f88f4d/include/elf/common.h#L933-L939
GNU_ABI_TAG = {
0: OS.LINUX,
1: OS.HURD,
2: OS.SOLARIS,
3: OS.FREEBSD,
4: OS.NETBSD,
5: OS.SYLLABLE,
6: OS.NACL,
}
@dataclass
class Phdr:
type: int
offset: int
vaddr: int
paddr: int
filesz: int
buf: bytes
@dataclass
class Shdr:
name: int
type: int
flags: int
addr: int
offset: int
size: int
link: int
entsize: int
buf: bytes
@classmethod
def from_viv(cls, section, buf: bytes) -> "Shdr":
return cls(
section.sh_name,
section.sh_type,
section.sh_flags,
section.sh_addr,
section.sh_offset,
section.sh_size,
section.sh_link,
section.sh_entsize,
buf,
)
class ELF:
def __init__(self, f: BinaryIO):
self.f = f
# these will all be initialized in `_parse()`
self.bitness: int
self.endian: str
self.e_phentsize: int
self.e_phnum: int
self.e_shentsize: int
self.e_shnum: int
self.phbuf: bytes
self.shbuf: bytes
self._parse()
def _parse(self):
self.f.seek(0x0)
self.file_header = self.f.read(0x40)
if not self.file_header.startswith(b"\x7fELF"):
raise CorruptElfFile("missing magic header")
ei_class, ei_data = struct.unpack_from("BB", self.file_header, 4)
logger.debug("ei_class: 0x%02x ei_data: 0x%02x", ei_class, ei_data)
if ei_class == 1:
self.bitness = 32
elif ei_class == 2:
self.bitness = 64
else:
raise CorruptElfFile(f"invalid ei_class: 0x{ei_class:02x}")
if ei_data == 1:
self.endian = "<"
elif ei_data == 2:
self.endian = ">"
else:
raise CorruptElfFile(f"not an ELF file: invalid ei_data: 0x{ei_data:02x}")
if self.bitness == 32:
e_phoff, e_shoff = struct.unpack_from(self.endian + "II", self.file_header, 0x1C)
self.e_phentsize, self.e_phnum = struct.unpack_from(self.endian + "HH", self.file_header, 0x2A)
self.e_shentsize, self.e_shnum = struct.unpack_from(self.endian + "HH", self.file_header, 0x2E)
elif self.bitness == 64:
e_phoff, e_shoff = struct.unpack_from(self.endian + "QQ", self.file_header, 0x20)
self.e_phentsize, self.e_phnum = struct.unpack_from(self.endian + "HH", self.file_header, 0x36)
self.e_shentsize, self.e_shnum = struct.unpack_from(self.endian + "HH", self.file_header, 0x3A)
else:
raise NotImplementedError()
logger.debug("e_phoff: 0x%02x e_phentsize: 0x%02x e_phnum: %d", e_phoff, self.e_phentsize, self.e_phnum)
self.f.seek(e_phoff)
program_header_size = self.e_phnum * self.e_phentsize
self.phbuf = self.f.read(program_header_size)
if len(self.phbuf) != program_header_size:
logger.warning("failed to read program headers")
self.e_phnum = 0
self.f.seek(e_shoff)
section_header_size = self.e_shnum * self.e_shentsize
self.shbuf = self.f.read(section_header_size)
if len(self.shbuf) != section_header_size:
logger.warning("failed to read section headers")
self.e_shnum = 0
OSABI = {
# via pyelftools: https://github.com/eliben/pyelftools/blob/0664de05ed2db3d39041e2d51d19622a8ef4fb0f/elftools/elf/enums.py#L35-L58
# some candidates are commented out because the are not useful values,
# at least when guessing OSes
# 0: "SYSV", # too often used when OS is not SYSV
1: OS.HPUX,
2: OS.NETBSD,
3: OS.LINUX,
4: OS.HURD,
5: OS._86OPEN,
6: OS.SOLARIS,
7: OS.AIX,
8: OS.IRIX,
9: OS.FREEBSD,
10: OS.TRU64,
11: OS.MODESTO,
12: OS.OPENBSD,
13: OS.OPENVMS,
14: OS.NSK,
15: OS.AROS,
16: OS.FENIXOS,
17: OS.CLOUD,
# 53: "SORTFIX", # i can't find any reference to this OS, i dont think it exists
# 64: "ARM_AEABI", # not an OS
# 97: "ARM", # not an OS
# 255: "STANDALONE", # not an OS
}
@property
def ei_osabi(self) -> Optional[OS]:
(ei_osabi,) = struct.unpack_from(self.endian + "B", self.file_header, 7)
return ELF.OSABI.get(ei_osabi)
MACHINE = {
# via https://refspecs.linuxfoundation.org/elf/gabi4+/ch4.eheader.html
1: "M32",
2: "SPARC",
3: "i386",
4: "68K",
5: "88K",
6: "486",
7: "860",
8: "MIPS",
9: "S370",
10: "MIPS_RS3_LE",
11: "RS6000",
15: "PA_RISC",
16: "nCUBE",
17: "VPP500",
18: "SPARC32PLUS",
19: "960",
20: "PPC",
21: "PPC64",
22: "S390",
23: "SPU",
36: "V800",
37: "FR20",
38: "RH32",
39: "RCE",
40: "ARM",
41: "ALPHA",
42: "SH",
43: "SPARCV9",
44: "TRICORE",
45: "ARC",
46: "H8_300",
47: "H8_300H",
48: "H8S",
49: "H8_500",
50: "IA_64",
51: "MIPS_X",
52: "COLDFIRE",
53: "68HC12",
54: "MMA",
55: "PCP",
56: "NCPU",
57: "NDR1",
58: "STARCORE",
59: "ME16",
60: "ST100",
61: "TINYJ",
62: "amd64",
63: "PDSP",
64: "PDP10",
65: "PDP11",
66: "FX66",
67: "ST9PLUS",
68: "ST7",
69: "68HC16",
70: "68HC11",
71: "68HC08",
72: "68HC05",
73: "SVX",
74: "ST19",
75: "VAX",
76: "CRIS",
77: "JAVELIN",
78: "FIREPATH",
79: "ZSP",
80: "MMIX",
81: "HUANY",
82: "PRISM",
83: "AVR",
84: "FR30",
85: "D10V",
86: "D30V",
87: "V850",
88: "M32R",
89: "MN10300",
90: "MN10200",
91: "PJ",
92: "OPENRISC",
93: "ARC_A5",
94: "XTENSA",
95: "VIDEOCORE",
96: "TMM_GPP",
97: "NS32K",
98: "TPC",
99: "SNP1K",
100: "ST200",
}
@property
def e_machine(self) -> Optional[str]:
(e_machine,) = struct.unpack_from(self.endian + "H", self.file_header, 0x12)
return ELF.MACHINE.get(e_machine)
def parse_program_header(self, i) -> Phdr:
phent_offset = i * self.e_phentsize
phent = self.phbuf[phent_offset : phent_offset + self.e_phentsize]
(p_type,) = struct.unpack_from(self.endian + "I", phent, 0x0)
logger.debug("ph:p_type: 0x%04x", p_type)
if self.bitness == 32:
p_offset, p_vaddr, p_paddr, p_filesz = struct.unpack_from(self.endian + "IIII", phent, 0x4)
elif self.bitness == 64:
p_offset, p_vaddr, p_paddr, p_filesz = struct.unpack_from(self.endian + "QQQQ", phent, 0x8)
else:
raise NotImplementedError()
logger.debug("ph:p_offset: 0x%02x p_filesz: 0x%04x", p_offset, p_filesz)
self.f.seek(p_offset)
buf = self.f.read(p_filesz)
if len(buf) != p_filesz:
raise ValueError("failed to read program header content")
return Phdr(p_type, p_offset, p_vaddr, p_paddr, p_filesz, buf)
@property
def program_headers(self):
for i in range(self.e_phnum):
try:
yield self.parse_program_header(i)
except ValueError:
continue
def parse_section_header(self, i) -> Shdr:
shent_offset = i * self.e_shentsize
shent = self.shbuf[shent_offset : shent_offset + self.e_shentsize]
if self.bitness == 32:
sh_name, sh_type, sh_flags, sh_addr, sh_offset, sh_size, sh_link, _, _, sh_entsize = struct.unpack_from(
self.endian + "IIIIIIIIII", shent, 0x0
)
elif self.bitness == 64:
sh_name, sh_type, sh_flags, sh_addr, sh_offset, sh_size, sh_link, _, _, sh_entsize = struct.unpack_from(
self.endian + "IIQQQQIIQQ", shent, 0x0
)
else:
raise NotImplementedError()
logger.debug("sh:sh_offset: 0x%02x sh_size: 0x%04x", sh_offset, sh_size)
self.f.seek(sh_offset)
buf = self.f.read(sh_size)
if len(buf) != sh_size:
raise ValueError("failed to read section header content")
return Shdr(sh_name, sh_type, sh_flags, sh_addr, sh_offset, sh_size, sh_link, sh_entsize, buf)
@property
def section_headers(self):
for i in range(self.e_shnum):
try:
yield self.parse_section_header(i)
except ValueError:
continue
@property
def linker(self):
PT_INTERP = 0x3
for phdr in self.program_headers:
if phdr.type != PT_INTERP:
continue
return read_cstr(phdr.buf, 0)
@property
def versions_needed(self) -> Dict[str, Set[str]]:
# symbol version requirements are stored in the .gnu.version_r section,
# which has type SHT_GNU_verneed (0x6ffffffe).
#
# this contains a linked list of ElfXX_Verneed structs,
# each referencing a linked list of ElfXX_Vernaux structs.
# strings are stored in the section referenced by the sh_link field of the section header.
# each Verneed struct contains a reference to the name of the library,
# each Vernaux struct contains a reference to the name of a symbol.
SHT_GNU_VERNEED = 0x6FFFFFFE
for shdr in self.section_headers:
if shdr.type != SHT_GNU_VERNEED:
continue
# the linked section contains strings referenced by the verneed structures.
linked_shdr = self.parse_section_header(shdr.link)
versions_needed = collections.defaultdict(set)
# read verneed structures from the start of the section
# until the vn_next link is 0x0.
# each entry describes a shared object that is required by this binary.
vn_offset = 0x0
while True:
# ElfXX_Verneed layout is the same on 32 and 64 bit
vn_version, vn_cnt, vn_file, vn_aux, vn_next = struct.unpack_from(
self.endian + "HHIII", shdr.buf, vn_offset
)
if vn_version != 1:
# unexpected format, don't try to keep parsing
break
# shared object names, like: "libdl.so.2"
so_name = read_cstr(linked_shdr.buf, vn_file)
# read vernaux structures linked from the verneed structure.
# there should be vn_cnt of these.
# each entry describes an ABI name required by the shared object.
vna_offset = vn_offset + vn_aux
for _ in range(vn_cnt):
# ElfXX_Vernaux layout is the same on 32 and 64 bit
_, _, _, vna_name, vna_next = struct.unpack_from(self.endian + "IHHII", shdr.buf, vna_offset)
# ABI names, like: "GLIBC_2.2.5"
abi = read_cstr(linked_shdr.buf, vna_name)
versions_needed[so_name].add(abi)
vna_offset += vna_next
vn_offset += vn_next
if vn_next == 0:
break
return dict(versions_needed)
return {}
@property
def dynamic_entries(self) -> Iterator[Tuple[int, int]]:
"""
read the entries from the dynamic section,
yielding the tag and value for each entry.
"""
DT_NULL = 0x0
PT_DYNAMIC = 0x2
for phdr in self.program_headers:
if phdr.type != PT_DYNAMIC:
continue
offset = 0x0
while True:
if self.bitness == 32:
d_tag, d_val = struct.unpack_from(self.endian + "II", phdr.buf, offset)
offset += 8
elif self.bitness == 64:
d_tag, d_val = struct.unpack_from(self.endian + "QQ", phdr.buf, offset)
offset += 16
else:
raise NotImplementedError()
if d_tag == DT_NULL:
break
yield d_tag, d_val
@property
def strtab(self) -> Optional[bytes]:
"""
fetch the bytes of the string table
referenced by the dynamic section.
"""
DT_STRTAB = 0x5
DT_STRSZ = 0xA
strtab_addr = None
strtab_size = None
for d_tag, d_val in self.dynamic_entries:
if d_tag == DT_STRTAB:
strtab_addr = d_val
break
for d_tag, d_val in self.dynamic_entries:
if d_tag == DT_STRSZ:
strtab_size = d_val
break
if strtab_addr is None:
return None
if strtab_size is None:
return None
strtab_offset = None
for shdr in self.section_headers:
# the section header address should be defined
if shdr.addr and shdr.addr <= strtab_addr < shdr.addr + shdr.size:
strtab_offset = shdr.offset + (strtab_addr - shdr.addr)
break
if strtab_offset is None:
return None
self.f.seek(strtab_offset)
strtab_buf = self.f.read(strtab_size)
if len(strtab_buf) != strtab_size:
return None
return strtab_buf
@property
def needed(self) -> Iterator[str]:
"""
read the names of DT_NEEDED entries from the dynamic section,
which correspond to dependencies on other shared objects,
like: `libpthread.so.0`
"""
DT_NEEDED = 0x1
strtab = self.strtab
if not strtab:
return
for d_tag, d_val in self.dynamic_entries:
if d_tag != DT_NEEDED:
continue
try:
yield read_cstr(strtab, d_val)
except UnicodeDecodeError as e:
logger.warning("failed to read DT_NEEDED entry: %s", str(e))
@property
def symtab(self) -> Optional[Tuple[Shdr, Shdr]]:
"""
fetch the Shdr for the symtab and the associated strtab.
"""
SHT_SYMTAB = 0x2
for shdr in self.section_headers:
if shdr.type != SHT_SYMTAB:
continue
# the linked section contains strings referenced by the symtab structures.
strtab_shdr = self.parse_section_header(shdr.link)
return shdr, strtab_shdr
return None
@dataclass
class ABITag:
os: OS
kmajor: int
kminor: int
kpatch: int
class PHNote:
def __init__(self, endian: str, buf: bytes):
self.endian = endian
self.buf = buf
# these will be initialized in `_parse()`
self.type_: int
self.descsz: int
self.name: str
self._parse()
def _parse(self):
namesz, self.descsz, self.type_ = struct.unpack_from(self.endian + "III", self.buf, 0x0)
name_offset = 0xC
self.desc_offset = name_offset + align(namesz, 0x4)
logger.debug("ph:namesz: 0x%02x descsz: 0x%02x type: 0x%04x", namesz, self.descsz, self.type_)
self.name = self.buf[name_offset : name_offset + namesz].partition(b"\x00")[0].decode("ascii")
logger.debug("name: %s", self.name)
@property
def abi_tag(self) -> Optional[ABITag]:
if self.type_ != 1:
# > The type field shall be 1.
# Linux Standard Base Specification 1.2
# ref: https://refspecs.linuxfoundation.org/LSB_1.2.0/gLSB/noteabitag.html
return None
if self.name != "GNU":
return None
if self.descsz < 16:
return None
desc = self.buf[self.desc_offset : self.desc_offset + self.descsz]
abi_tag, kmajor, kminor, kpatch = struct.unpack_from(self.endian + "IIII", desc, 0x0)
logger.debug("GNU_ABI_TAG: 0x%02x", abi_tag)
os = GNU_ABI_TAG.get(abi_tag)
if not os:
return None
logger.debug("abi tag: %s earliest compatible kernel: %d.%d.%d", os, kmajor, kminor, kpatch)
return ABITag(os, kmajor, kminor, kpatch)
class SHNote:
def __init__(self, endian: str, buf: bytes):
self.endian = endian
self.buf = buf
# these will be initialized in `_parse()`
self.type_: int
self.descsz: int
self.name: str
self._parse()
def _parse(self):
namesz, self.descsz, self.type_ = struct.unpack_from(self.endian + "III", self.buf, 0x0)
name_offset = 0xC
self.desc_offset = name_offset + align(namesz, 0x4)
logger.debug("sh:namesz: 0x%02x descsz: 0x%02x type: 0x%04x", namesz, self.descsz, self.type_)
name_buf = self.buf[name_offset : name_offset + namesz]
self.name = read_cstr(name_buf, 0x0)
logger.debug("sh:name: %s", self.name)
@property
def abi_tag(self) -> Optional[ABITag]:
if self.name != "GNU":
return None
if self.descsz < 16:
return None
desc = self.buf[self.desc_offset : self.desc_offset + self.descsz]
abi_tag, kmajor, kminor, kpatch = struct.unpack_from(self.endian + "IIII", desc, 0x0)
logger.debug("GNU_ABI_TAG: 0x%02x", abi_tag)
os = GNU_ABI_TAG.get(abi_tag)
if not os:
return None
logger.debug("abi tag: %s earliest compatible kernel: %d.%d.%d", os, kmajor, kminor, kpatch)
return ABITag(os, kmajor, kminor, kpatch)
@dataclass
class Symbol:
name_offset: int
value: int
size: int
info: int
other: int
shndx: int
class SymTab:
def __init__(
self,
endian: str,
bitness: int,
symtab: Shdr,
strtab: Shdr,
) -> None:
self.symbols: List[Symbol] = []
self.symtab = symtab
self.strtab = strtab
self._parse(endian, bitness, symtab.buf)
def _parse(self, endian: str, bitness: int, symtab_buf: bytes) -> None:
"""
return the symbol's information in
the order specified by sys/elf32.h
"""
if self.symtab.entsize == 0:
return
for i in range(int(len(self.symtab.buf) / self.symtab.entsize)):
if bitness == 32:
name_offset, value, size, info, other, shndx = struct.unpack_from(
endian + "IIIBBH", symtab_buf, i * self.symtab.entsize
)
elif bitness == 64:
name_offset, info, other, shndx, value, size = struct.unpack_from(
endian + "IBBHQQ", symtab_buf, i * self.symtab.entsize
)
self.symbols.append(Symbol(name_offset, value, size, info, other, shndx))
def get_name(self, symbol: Symbol) -> str:
"""
fetch a symbol's name from symtab's
associated strings' section (SHT_STRTAB)
"""
if not self.strtab:
raise ValueError("no strings found")
for i in range(symbol.name_offset, self.strtab.size):
if self.strtab.buf[i] == 0:
return self.strtab.buf[symbol.name_offset : i].decode("utf-8")
raise ValueError("symbol name not found")
def get_symbols(self) -> Iterator[Symbol]:
"""
return a tuple: (name, value, size, info, other, shndx)
for each symbol contained in the symbol table
"""
yield from self.symbols
@classmethod
def from_viv(cls, elf: Elf.Elf) -> Optional["SymTab"]:
endian = "<" if elf.getEndian() == 0 else ">"
bitness = elf.bits
SHT_SYMTAB = 0x2
for section in elf.sections:
if section.sh_type == SHT_SYMTAB:
strtab_section = elf.sections[section.sh_link]
sh_symtab = Shdr.from_viv(section, elf.readAtOffset(section.sh_offset, section.sh_size))
sh_strtab = Shdr.from_viv(
strtab_section, elf.readAtOffset(strtab_section.sh_offset, strtab_section.sh_size)
)
try:
return cls(endian, bitness, sh_symtab, sh_strtab)
except NameError:
return None
except Exception:
# all exceptions that could be encountered by
# cls._parse() imply a faulty symbol's table.
raise CorruptElfFile("malformed symbol's table")
def guess_os_from_osabi(elf: ELF) -> Optional[OS]:
return elf.ei_osabi
def guess_os_from_ph_notes(elf: ELF) -> Optional[OS]:
# search for PT_NOTE sections that specify an OS
# for example, on Linux there is a GNU section with minimum kernel version
PT_NOTE = 0x4
for phdr in elf.program_headers:
if phdr.type != PT_NOTE:
continue
note = PHNote(elf.endian, phdr.buf)
if note.type_ != 1:
# > The type field shall be 1.
# Linux Standard Base Specification 1.2
# ref: https://refspecs.linuxfoundation.org/LSB_1.2.0/gLSB/noteabitag.html
continue
if note.name == "Linux":
logger.debug("note owner: %s", "LINUX")
return OS.LINUX
elif note.name == "OpenBSD":
logger.debug("note owner: %s", "OPENBSD")
return OS.OPENBSD
elif note.name == "NetBSD":
logger.debug("note owner: %s", "NETBSD")
return OS.NETBSD
elif note.name == "FreeBSD":
logger.debug("note owner: %s", "FREEBSD")
return OS.FREEBSD
elif note.name == "Android":
logger.debug("note owner: %s", "Android")
# see the following for parsing the structure:
# https://android.googlesource.com/platform/ndk/+/master/parse_elfnote.py
return OS.ANDROID
elif note.name == "GNU":
abi_tag = note.abi_tag
if abi_tag:
return abi_tag.os
else:
# cannot make a guess about the OS, but probably linux or hurd
pass
return None
def guess_os_from_sh_notes(elf: ELF) -> Optional[OS]:
# search for notes stored in sections that aren't visible in program headers.
# e.g. .note.Linux in Linux kernel modules.
SHT_NOTE = 0x7
for shdr in elf.section_headers:
if shdr.type != SHT_NOTE:
continue
note = SHNote(elf.endian, shdr.buf)
if note.name == "Linux":
logger.debug("note owner: %s", "LINUX")
return OS.LINUX
elif note.name == "OpenBSD":
logger.debug("note owner: %s", "OPENBSD")
return OS.OPENBSD
elif note.name == "NetBSD":
logger.debug("note owner: %s", "NETBSD")
return OS.NETBSD
elif note.name == "FreeBSD":
logger.debug("note owner: %s", "FREEBSD")
return OS.FREEBSD
elif note.name == "GNU":
abi_tag = note.abi_tag
if abi_tag:
return abi_tag.os
else:
# cannot make a guess about the OS, but probably linux or hurd
pass
return None
def guess_os_from_linker(elf: ELF) -> Optional[OS]:
# search for recognizable dynamic linkers (interpreters)
# for example, on linux, we see file paths like: /lib64/ld-linux-x86-64.so.2
linker = elf.linker
if linker and "ld-linux" in elf.linker:
return OS.LINUX
return None
def guess_os_from_abi_versions_needed(elf: ELF) -> Optional[OS]:
# then lets look for GLIBC symbol versioning requirements.
# this will let us guess about linux/hurd in some cases.
versions_needed = elf.versions_needed
if any(abi.startswith("GLIBC") for abi in itertools.chain(*versions_needed.values())):
# there are any GLIBC versions needed
if elf.e_machine != "i386":
# GLIBC runs on Linux and Hurd.
# for Hurd, its *only* on i386.
# so if we're not on i386, then we're on Linux.
return OS.LINUX
else:
# we're on i386, so we could be on either Linux or Hurd.
linker = elf.linker
if linker and "ld-linux" in linker:
return OS.LINUX
elif linker and "/ld.so" in linker:
return OS.HURD
else:
# we don't have any good guesses based on versions needed
pass
return None
def guess_os_from_needed_dependencies(elf: ELF) -> Optional[OS]:
for needed in elf.needed:
if needed.startswith("libmachuser.so"):
return OS.HURD
if needed.startswith("libhurduser.so"):
return OS.HURD
if needed.startswith("libandroid.so"):
return OS.ANDROID
return None
def guess_os_from_symtab(elf: ELF) -> Optional[OS]:
shdrs = elf.symtab
if not shdrs:
# executable does not contain a symbol table
# or the symbol's names are stripped
return None
symtab_shdr, strtab_shdr = shdrs
symtab = SymTab(elf.endian, elf.bitness, symtab_shdr, strtab_shdr)
keywords = {
OS.LINUX: [
"linux",
"/linux/",
],
}
for symbol in symtab.get_symbols():
sym_name = symtab.get_name(symbol)
for os, hints in keywords.items():
if any(hint in sym_name for hint in hints):
return os
return None
def detect_elf_os(f) -> str:
"""
f: type Union[BinaryIO, IDAIO, GHIDRAIO]
"""
try:
elf = ELF(f)
except Exception as e:
logger.warning("Error parsing ELF file: %s", e)
return "unknown"
try:
osabi_guess = guess_os_from_osabi(elf)
logger.debug("guess: osabi: %s", osabi_guess)
except Exception as e:
logger.warning("Error guessing OS from OSABI: %s", e)
osabi_guess = None
try:
ph_notes_guess = guess_os_from_ph_notes(elf)
logger.debug("guess: ph notes: %s", ph_notes_guess)
except Exception as e:
logger.warning("Error guessing OS from program header notes: %s", e)
ph_notes_guess = None
try:
sh_notes_guess = guess_os_from_sh_notes(elf)
logger.debug("guess: sh notes: %s", sh_notes_guess)
except Exception as e:
logger.warning("Error guessing OS from section header notes: %s", e)
sh_notes_guess = None
try:
linker_guess = guess_os_from_linker(elf)
logger.debug("guess: linker: %s", linker_guess)
except Exception as e:
logger.warning("Error guessing OS from linker: %s", e)
linker_guess = None
try:
abi_versions_needed_guess = guess_os_from_abi_versions_needed(elf)
logger.debug("guess: ABI versions needed: %s", abi_versions_needed_guess)
except Exception as e:
logger.warning("Error guessing OS from ABI versions needed: %s", e)
abi_versions_needed_guess = None
try:
needed_dependencies_guess = guess_os_from_needed_dependencies(elf)
logger.debug("guess: needed dependencies: %s", needed_dependencies_guess)
except Exception as e:
logger.warning("Error guessing OS from needed dependencies: %s", e)
needed_dependencies_guess = None
try:
symtab_guess = guess_os_from_symtab(elf)
logger.debug("guess: pertinent symbol name: %s", symtab_guess)
except Exception as e:
logger.warning("Error guessing OS from symbol table: %s", e)
symtab_guess = None
ret = None
if osabi_guess:
ret = osabi_guess
elif ph_notes_guess:
ret = ph_notes_guess
elif sh_notes_guess:
ret = sh_notes_guess
elif linker_guess:
ret = linker_guess
elif abi_versions_needed_guess:
ret = abi_versions_needed_guess
elif needed_dependencies_guess:
ret = needed_dependencies_guess
elif symtab_guess:
ret = symtab_guess
return ret.value if ret is not None else "unknown"
def detect_elf_arch(f: BinaryIO) -> str:
return ELF(f).e_machine or "unknown"

View File

@@ -1,203 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import io
import logging
from typing import Tuple, Iterator
from pathlib import Path
from elftools.elf.elffile import ELFFile, SymbolTableSection
from elftools.elf.relocation import RelocationSection
import capa.features.extractors.common
from capa.features.file import Export, Import, Section
from capa.features.common import OS, FORMAT_ELF, Arch, Format, Feature
from capa.features.address import NO_ADDRESS, FileOffsetAddress, AbsoluteVirtualAddress
from capa.features.extractors.base_extractor import FeatureExtractor
logger = logging.getLogger(__name__)
def extract_file_export_names(elf: ELFFile, **kwargs):
for section in elf.iter_sections():
if not isinstance(section, SymbolTableSection):
continue
if section["sh_entsize"] == 0:
logger.debug("Symbol table '%s' has a sh_entsize of zero!", section.name)
continue
logger.debug("Symbol table '%s' contains %s entries:", section.name, section.num_symbols())
for symbol in section.iter_symbols():
# The following conditions are based on the following article
# http://www.m4b.io/elf/export/binary/analysis/2015/05/25/what-is-an-elf-export.html
if not symbol.name:
continue
if symbol.entry.st_info.type not in ["STT_FUNC", "STT_OBJECT", "STT_IFUNC"]:
continue
if symbol.entry.st_value == 0:
continue
if symbol.entry.st_shndx == "SHN_UNDEF":
continue
yield Export(symbol.name), AbsoluteVirtualAddress(symbol.entry.st_value)
def extract_file_import_names(elf: ELFFile, **kwargs):
# Create a dictionary to store symbol names by their index
symbol_names = {}
# Extract symbol names and store them in the dictionary
for section in elf.iter_sections():
if not isinstance(section, SymbolTableSection):
continue
for _, symbol in enumerate(section.iter_symbols()):
# The following conditions are based on the following article
# http://www.m4b.io/elf/export/binary/analysis/2015/05/25/what-is-an-elf-export.html
if not symbol.name:
continue
if symbol.entry.st_info.type not in ["STT_FUNC", "STT_OBJECT", "STT_IFUNC"]:
continue
if symbol.entry.st_value != 0:
continue
if symbol.entry.st_shndx != "SHN_UNDEF":
continue
if symbol.entry.st_name == 0:
continue
symbol_names[_] = symbol.name
for section in elf.iter_sections():
if not isinstance(section, RelocationSection):
continue
if section["sh_entsize"] == 0:
logger.debug("Symbol table '%s' has a sh_entsize of zero!", section.name)
continue
logger.debug("Symbol table '%s' contains %s entries:", section.name, section.num_relocations())
for relocation in section.iter_relocations():
# Extract the symbol name from the symbol table using the symbol index in the relocation
if relocation["r_info_sym"] not in symbol_names:
continue
yield Import(symbol_names[relocation["r_info_sym"]]), FileOffsetAddress(relocation["r_offset"])
def extract_file_section_names(elf: ELFFile, **kwargs):
for section in elf.iter_sections():
if section.name:
yield Section(section.name), AbsoluteVirtualAddress(section.header.sh_addr)
elif section.is_null():
yield Section("NULL"), AbsoluteVirtualAddress(section.header.sh_addr)
def extract_file_strings(buf, **kwargs):
yield from capa.features.extractors.common.extract_file_strings(buf)
def extract_file_os(elf: ELFFile, buf, **kwargs):
# our current approach does not always get an OS value, e.g. for packed samples
# for file limitation purposes, we're more lax here
try:
os_tuple = next(capa.features.extractors.common.extract_os(buf))
yield os_tuple
except StopIteration:
yield OS("unknown"), NO_ADDRESS
def extract_file_format(**kwargs):
yield Format(FORMAT_ELF), NO_ADDRESS
def extract_file_arch(elf: ELFFile, **kwargs):
arch = elf.get_machine_arch()
if arch == "x86":
yield Arch("i386"), NO_ADDRESS
elif arch == "x64":
yield Arch("amd64"), NO_ADDRESS
else:
logger.warning("unsupported architecture: %s", arch)
def extract_file_features(elf: ELFFile, buf: bytes) -> Iterator[Tuple[Feature, int]]:
for file_handler in FILE_HANDLERS:
for feature, addr in file_handler(elf=elf, buf=buf): # type: ignore
yield feature, addr
FILE_HANDLERS = (
extract_file_export_names,
extract_file_import_names,
extract_file_section_names,
extract_file_strings,
# no library matching
extract_file_format,
)
def extract_global_features(elf: ELFFile, buf: bytes) -> Iterator[Tuple[Feature, int]]:
for global_handler in GLOBAL_HANDLERS:
for feature, addr in global_handler(elf=elf, buf=buf): # type: ignore
yield feature, addr
GLOBAL_HANDLERS = (
extract_file_os,
extract_file_arch,
)
class ElfFeatureExtractor(FeatureExtractor):
def __init__(self, path: Path):
super().__init__()
self.path: Path = path
self.elf = ELFFile(io.BytesIO(path.read_bytes()))
def get_base_address(self):
# virtual address of the first segment with type LOAD
for segment in self.elf.iter_segments():
if segment.header.p_type == "PT_LOAD":
return AbsoluteVirtualAddress(segment.header.p_vaddr)
def extract_global_features(self):
buf = self.path.read_bytes()
for feature, addr in extract_global_features(self.elf, buf):
yield feature, addr
def extract_file_features(self):
buf = self.path.read_bytes()
for feature, addr in extract_file_features(self.elf, buf):
yield feature, addr
def get_functions(self):
raise NotImplementedError("ElfFeatureExtractor can only be used to extract file features")
def extract_function_features(self, f):
raise NotImplementedError("ElfFeatureExtractor can only be used to extract file features")
def get_basic_blocks(self, f):
raise NotImplementedError("ElfFeatureExtractor can only be used to extract file features")
def extract_basic_block_features(self, f, bb):
raise NotImplementedError("ElfFeatureExtractor can only be used to extract file features")
def get_instructions(self, f, bb):
raise NotImplementedError("ElfFeatureExtractor can only be used to extract file features")
def extract_insn_features(self, f, bb, insn):
raise NotImplementedError("ElfFeatureExtractor can only be used to extract file features")
def is_library_function(self, addr):
raise NotImplementedError("ElfFeatureExtractor can only be used to extract file features")
def get_function_name(self, addr):
raise NotImplementedError("ElfFeatureExtractor can only be used to extract file features")

View File

@@ -1,152 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import string
import struct
from typing import Tuple, Iterator
import ghidra
from ghidra.program.model.lang import OperandType
import capa.features.extractors.ghidra.helpers
from capa.features.common import Feature, Characteristic
from capa.features.address import Address
from capa.features.basicblock import BasicBlock
from capa.features.extractors.helpers import MIN_STACKSTRING_LEN
from capa.features.extractors.base_extractor import BBHandle, FunctionHandle
def get_printable_len(op: ghidra.program.model.scalar.Scalar) -> int:
"""Return string length if all operand bytes are ascii or utf16-le printable"""
op_bit_len = op.bitLength()
op_byte_len = op_bit_len // 8
op_val = op.getValue()
if op_bit_len == 8:
chars = struct.pack("<B", op_val & 0xFF)
elif op_bit_len == 16:
chars = struct.pack("<H", op_val & 0xFFFF)
elif op_bit_len == 32:
chars = struct.pack("<I", op_val & 0xFFFFFFFF)
elif op_bit_len == 64:
chars = struct.pack("<Q", op_val & 0xFFFFFFFFFFFFFFFF)
else:
raise ValueError(f"Unhandled operand data type 0x{op_bit_len:x}.")
def is_printable_ascii(chars_: bytes):
return all(c < 127 and chr(c) in string.printable for c in chars_)
def is_printable_utf16le(chars_: bytes):
if all(c == 0x00 for c in chars_[1::2]):
return is_printable_ascii(chars_[::2])
if is_printable_ascii(chars):
return op_byte_len
if is_printable_utf16le(chars):
return op_byte_len
return 0
def is_mov_imm_to_stack(insn: ghidra.program.database.code.InstructionDB) -> bool:
"""verify instruction moves immediate onto stack"""
# Ghidra will Bitwise OR the OperandTypes to assign multiple
# i.e., the first operand is a stackvar (dynamically allocated),
# and the second is a scalar value (single int/char/float/etc.)
mov_its_ops = [(OperandType.ADDRESS | OperandType.DYNAMIC), OperandType.SCALAR]
found = False
# MOV dword ptr [EBP + local_*], 0x65
if insn.getMnemonicString().startswith("MOV"):
found = all(insn.getOperandType(i) == mov_its_ops[i] for i in range(2))
return found
def bb_contains_stackstring(bb: ghidra.program.model.block.CodeBlock) -> bool:
"""check basic block for stackstring indicators
true if basic block contains enough moves of constant bytes to the stack
"""
count = 0
for insn in currentProgram().getListing().getInstructions(bb, True): # type: ignore [name-defined] # noqa: F821
if is_mov_imm_to_stack(insn):
count += get_printable_len(insn.getScalar(1))
if count > MIN_STACKSTRING_LEN:
return True
return False
def _bb_has_tight_loop(bb: ghidra.program.model.block.CodeBlock):
"""
parse tight loops, true if last instruction in basic block branches to bb start
"""
# Reverse Ordered, first InstructionDB
last_insn = currentProgram().getListing().getInstructions(bb, False).next() # type: ignore [name-defined] # noqa: F821
if last_insn.getFlowType().isJump():
return last_insn.getAddress(0) == bb.getMinAddress()
return False
def extract_bb_stackstring(fh: FunctionHandle, bbh: BBHandle) -> Iterator[Tuple[Feature, Address]]:
"""extract stackstring indicators from basic block"""
bb: ghidra.program.model.block.CodeBlock = bbh.inner
if bb_contains_stackstring(bb):
yield Characteristic("stack string"), bbh.address
def extract_bb_tight_loop(fh: FunctionHandle, bbh: BBHandle) -> Iterator[Tuple[Feature, Address]]:
"""check basic block for tight loop indicators"""
bb: ghidra.program.model.block.CodeBlock = bbh.inner
if _bb_has_tight_loop(bb):
yield Characteristic("tight loop"), bbh.address
BASIC_BLOCK_HANDLERS = (
extract_bb_tight_loop,
extract_bb_stackstring,
)
def extract_features(fh: FunctionHandle, bbh: BBHandle) -> Iterator[Tuple[Feature, Address]]:
"""
extract features from the given basic block.
args:
bb: the basic block to process.
yields:
Tuple[Feature, int]: the features and their location found in this basic block.
"""
yield BasicBlock(), bbh.address
for bb_handler in BASIC_BLOCK_HANDLERS:
for feature, addr in bb_handler(fh, bbh):
yield feature, addr
def main():
features = []
from capa.features.extractors.ghidra.extractor import GhidraFeatureExtractor
for fh in GhidraFeatureExtractor().get_functions():
for bbh in capa.features.extractors.ghidra.helpers.get_function_blocks(fh):
features.extend(list(extract_features(fh, bbh)))
import pprint
pprint.pprint(features) # noqa: T203
if __name__ == "__main__":
main()

View File

@@ -1,75 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
from typing import List, Tuple, Iterator
import capa.features.extractors.ghidra.file
import capa.features.extractors.ghidra.insn
import capa.features.extractors.ghidra.global_
import capa.features.extractors.ghidra.function
import capa.features.extractors.ghidra.basicblock
from capa.features.common import Feature
from capa.features.address import Address, AbsoluteVirtualAddress
from capa.features.extractors.base_extractor import BBHandle, InsnHandle, FunctionHandle, FeatureExtractor
class GhidraFeatureExtractor(FeatureExtractor):
def __init__(self):
super().__init__()
import capa.features.extractors.ghidra.helpers as ghidra_helpers
self.global_features: List[Tuple[Feature, Address]] = []
self.global_features.extend(capa.features.extractors.ghidra.file.extract_file_format())
self.global_features.extend(capa.features.extractors.ghidra.global_.extract_os())
self.global_features.extend(capa.features.extractors.ghidra.global_.extract_arch())
self.imports = ghidra_helpers.get_file_imports()
self.externs = ghidra_helpers.get_file_externs()
self.fakes = ghidra_helpers.map_fake_import_addrs()
def get_base_address(self):
return AbsoluteVirtualAddress(currentProgram().getImageBase().getOffset()) # type: ignore [name-defined] # noqa: F821
def extract_global_features(self):
yield from self.global_features
def extract_file_features(self):
yield from capa.features.extractors.ghidra.file.extract_features()
def get_functions(self) -> Iterator[FunctionHandle]:
import capa.features.extractors.ghidra.helpers as ghidra_helpers
for fhandle in ghidra_helpers.get_function_symbols():
fh: FunctionHandle = FunctionHandle(
address=AbsoluteVirtualAddress(fhandle.getEntryPoint().getOffset()),
inner=fhandle,
ctx={"imports_cache": self.imports, "externs_cache": self.externs, "fakes_cache": self.fakes},
)
yield fh
@staticmethod
def get_function(addr: int) -> FunctionHandle:
func = getFunctionContaining(toAddr(addr)) # type: ignore [name-defined] # noqa: F821
return FunctionHandle(address=AbsoluteVirtualAddress(func.getEntryPoint().getOffset()), inner=func)
def extract_function_features(self, fh: FunctionHandle) -> Iterator[Tuple[Feature, Address]]:
yield from capa.features.extractors.ghidra.function.extract_features(fh)
def get_basic_blocks(self, fh: FunctionHandle) -> Iterator[BBHandle]:
import capa.features.extractors.ghidra.helpers as ghidra_helpers
yield from ghidra_helpers.get_function_blocks(fh)
def extract_basic_block_features(self, fh: FunctionHandle, bbh: BBHandle) -> Iterator[Tuple[Feature, Address]]:
yield from capa.features.extractors.ghidra.basicblock.extract_features(fh, bbh)
def get_instructions(self, fh: FunctionHandle, bbh: BBHandle) -> Iterator[InsnHandle]:
import capa.features.extractors.ghidra.helpers as ghidra_helpers
yield from ghidra_helpers.get_insn_in_range(bbh)
def extract_insn_features(self, fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle):
yield from capa.features.extractors.ghidra.insn.extract_features(fh, bbh, ih)

View File

@@ -1,202 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import re
import struct
from typing import List, Tuple, Iterator
from ghidra.program.model.symbol import SourceType, SymbolType
import capa.features.extractors.common
import capa.features.extractors.helpers
import capa.features.extractors.strings
import capa.features.extractors.ghidra.helpers
from capa.features.file import Export, Import, Section, FunctionName
from capa.features.common import FORMAT_PE, FORMAT_ELF, Format, String, Feature, Characteristic
from capa.features.address import NO_ADDRESS, Address, FileOffsetAddress, AbsoluteVirtualAddress
MAX_OFFSET_PE_AFTER_MZ = 0x200
def find_embedded_pe(block_bytez: bytes, mz_xor: List[Tuple[bytes, bytes, int]]) -> Iterator[Tuple[int, int]]:
"""check segment for embedded PE
adapted for Ghidra from:
https://github.com/vivisect/vivisect/blob/91e8419a861f4977https://github.com/vivisect/vivisect/blob/91e8419a861f49779f18316f155311967e696836/PE/carve.py#L259f18316f155311967e696836/PE/carve.py#L25
"""
todo = []
for mzx, pex, i in mz_xor:
for match in re.finditer(re.escape(mzx), block_bytez):
todo.append((match.start(), mzx, pex, i))
seg_max = len(block_bytez) # type: ignore [name-defined] # noqa: F821
while len(todo):
off, mzx, pex, i = todo.pop()
# MZ header has one field we will check e_lfanew is at 0x3c
e_lfanew = off + 0x3C
if seg_max < e_lfanew + 4:
continue
e_lfanew_bytes = block_bytez[e_lfanew : e_lfanew + 4]
newoff = struct.unpack("<I", capa.features.extractors.helpers.xor_static(e_lfanew_bytes, i))[0]
# assume XOR'd "PE" bytes exist within threshold
if newoff > MAX_OFFSET_PE_AFTER_MZ:
continue
peoff = off + newoff
if seg_max < peoff + 2:
continue
pe_bytes = block_bytez[peoff : peoff + 2]
if pe_bytes == pex:
yield off, i
def extract_file_embedded_pe() -> Iterator[Tuple[Feature, Address]]:
"""extract embedded PE features"""
# pre-compute XOR pairs
mz_xor: List[Tuple[bytes, bytes, int]] = [
(
capa.features.extractors.helpers.xor_static(b"MZ", i),
capa.features.extractors.helpers.xor_static(b"PE", i),
i,
)
for i in range(256)
]
for block in currentProgram().getMemory().getBlocks(): # type: ignore [name-defined] # noqa: F821
if not all((block.isLoaded(), block.isInitialized(), "Headers" not in block.getName())):
continue
for off, _ in find_embedded_pe(capa.features.extractors.ghidra.helpers.get_block_bytes(block), mz_xor):
# add offset back to block start
ea: int = block.getStart().add(off).getOffset()
yield Characteristic("embedded pe"), FileOffsetAddress(ea)
def extract_file_export_names() -> Iterator[Tuple[Feature, Address]]:
"""extract function exports"""
st = currentProgram().getSymbolTable() # type: ignore [name-defined] # noqa: F821
for addr in st.getExternalEntryPointIterator():
yield Export(st.getPrimarySymbol(addr).getName()), AbsoluteVirtualAddress(addr.getOffset())
def extract_file_import_names() -> Iterator[Tuple[Feature, Address]]:
"""extract function imports
1. imports by ordinal:
- modulename.#ordinal
2. imports by name, results in two features to support importname-only
matching:
- modulename.importname
- importname
"""
for f in currentProgram().getFunctionManager().getExternalFunctions(): # type: ignore [name-defined] # noqa: F821
for r in f.getSymbol().getReferences():
if r.getReferenceType().isData():
addr = r.getFromAddress().getOffset() # gets pointer to fake external addr
fstr = f.toString().split("::") # format: MODULE.dll::import / MODULE::Ordinal_*
if "Ordinal_" in fstr[1]:
fstr[1] = f"#{fstr[1].split('_')[1]}"
for name in capa.features.extractors.helpers.generate_symbols(fstr[0][:-4], fstr[1]):
yield Import(name), AbsoluteVirtualAddress(addr)
def extract_file_section_names() -> Iterator[Tuple[Feature, Address]]:
"""extract section names"""
for block in currentProgram().getMemory().getBlocks(): # type: ignore [name-defined] # noqa: F821
yield Section(block.getName()), AbsoluteVirtualAddress(block.getStart().getOffset())
def extract_file_strings() -> Iterator[Tuple[Feature, Address]]:
"""extract ASCII and UTF-16 LE strings"""
for block in currentProgram().getMemory().getBlocks(): # type: ignore [name-defined] # noqa: F821
if block.isInitialized():
p_bytes = capa.features.extractors.ghidra.helpers.get_block_bytes(block)
for s in capa.features.extractors.strings.extract_ascii_strings(p_bytes):
offset = block.getStart().getOffset() + s.offset
yield String(s.s), FileOffsetAddress(offset)
for s in capa.features.extractors.strings.extract_unicode_strings(p_bytes):
offset = block.getStart().getOffset() + s.offset
yield String(s.s), FileOffsetAddress(offset)
def extract_file_function_names() -> Iterator[Tuple[Feature, Address]]:
"""
extract the names of statically-linked library functions.
"""
for sym in currentProgram().getSymbolTable().getAllSymbols(True): # type: ignore [name-defined] # noqa: F821
# .isExternal() misses more than this config for the function symbols
if sym.getSymbolType() == SymbolType.FUNCTION and sym.getSource() == SourceType.ANALYSIS and sym.isGlobal():
name = sym.getName() # starts to resolve names based on Ghidra's FidDB
if name.startswith("FID_conflict:"): # format: FID_conflict:<function-name>
name = name[13:]
addr = AbsoluteVirtualAddress(sym.getAddress().getOffset())
yield FunctionName(name), addr
if name.startswith("_"):
# some linkers may prefix linked routines with a `_` to avoid name collisions.
# extract features for both the mangled and un-mangled representations.
# e.g. `_fwrite` -> `fwrite`
# see: https://stackoverflow.com/a/2628384/87207
yield FunctionName(name[1:]), addr
def extract_file_format() -> Iterator[Tuple[Feature, Address]]:
ef = currentProgram().getExecutableFormat() # type: ignore [name-defined] # noqa: F821
if "PE" in ef:
yield Format(FORMAT_PE), NO_ADDRESS
elif "ELF" in ef:
yield Format(FORMAT_ELF), NO_ADDRESS
elif "Raw" in ef:
# no file type to return when processing a binary file, but we want to continue processing
return
else:
raise NotImplementedError(f"unexpected file format: {ef}")
def extract_features() -> Iterator[Tuple[Feature, Address]]:
"""extract file features"""
for file_handler in FILE_HANDLERS:
for feature, addr in file_handler():
yield feature, addr
FILE_HANDLERS = (
extract_file_embedded_pe,
extract_file_export_names,
extract_file_import_names,
extract_file_section_names,
extract_file_strings,
extract_file_function_names,
extract_file_format,
)
def main():
""" """
import pprint
pprint.pprint(list(extract_features())) # noqa: T203
if __name__ == "__main__":
main()

View File

@@ -1,73 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
from typing import Tuple, Iterator
import ghidra
from ghidra.program.model.block import BasicBlockModel, SimpleBlockIterator
import capa.features.extractors.ghidra.helpers
from capa.features.common import Feature, Characteristic
from capa.features.address import Address, AbsoluteVirtualAddress
from capa.features.extractors import loops
from capa.features.extractors.base_extractor import FunctionHandle
def extract_function_calls_to(fh: FunctionHandle):
"""extract callers to a function"""
f: ghidra.program.database.function.FunctionDB = fh.inner
for ref in f.getSymbol().getReferences():
if ref.getReferenceType().isCall():
yield Characteristic("calls to"), AbsoluteVirtualAddress(ref.getFromAddress().getOffset())
def extract_function_loop(fh: FunctionHandle):
f: ghidra.program.database.function.FunctionDB = fh.inner
edges = []
for block in SimpleBlockIterator(BasicBlockModel(currentProgram()), f.getBody(), monitor()): # type: ignore [name-defined] # noqa: F821
dests = block.getDestinations(monitor()) # type: ignore [name-defined] # noqa: F821
s_addrs = block.getStartAddresses()
while dests.hasNext(): # For loop throws Python TypeError
for addr in s_addrs:
edges.append((addr.getOffset(), dests.next().getDestinationAddress().getOffset()))
if loops.has_loop(edges):
yield Characteristic("loop"), AbsoluteVirtualAddress(f.getEntryPoint().getOffset())
def extract_recursive_call(fh: FunctionHandle):
f: ghidra.program.database.function.FunctionDB = fh.inner
for func in f.getCalledFunctions(monitor()): # type: ignore [name-defined] # noqa: F821
if func.getEntryPoint().getOffset() == f.getEntryPoint().getOffset():
yield Characteristic("recursive call"), AbsoluteVirtualAddress(f.getEntryPoint().getOffset())
def extract_features(fh: FunctionHandle) -> Iterator[Tuple[Feature, Address]]:
for func_handler in FUNCTION_HANDLERS:
for feature, addr in func_handler(fh):
yield feature, addr
FUNCTION_HANDLERS = (extract_function_calls_to, extract_function_loop, extract_recursive_call)
def main():
""" """
features = []
for fhandle in capa.features.extractors.ghidra.helpers.get_function_symbols():
features.extend(list(extract_features(fhandle)))
import pprint
pprint.pprint(features) # noqa: T203
if __name__ == "__main__":
main()

View File

@@ -1,67 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import logging
import contextlib
from typing import Tuple, Iterator
import capa.ghidra.helpers
import capa.features.extractors.elf
import capa.features.extractors.ghidra.helpers
from capa.features.common import OS, ARCH_I386, ARCH_AMD64, OS_WINDOWS, Arch, Feature
from capa.features.address import NO_ADDRESS, Address
logger = logging.getLogger(__name__)
def extract_os() -> Iterator[Tuple[Feature, Address]]:
format_name: str = currentProgram().getExecutableFormat() # type: ignore [name-defined] # noqa: F821
if "PE" in format_name:
yield OS(OS_WINDOWS), NO_ADDRESS
elif "ELF" in format_name:
with contextlib.closing(capa.ghidra.helpers.GHIDRAIO()) as f:
os = capa.features.extractors.elf.detect_elf_os(f)
yield OS(os), NO_ADDRESS
else:
# we likely end up here:
# 1. handling shellcode, or
# 2. handling a new file format (e.g. macho)
#
# for (1) we can't do much - its shellcode and all bets are off.
# we could maybe accept a further CLI argument to specify the OS,
# but i think this would be rarely used.
# rules that rely on OS conditions will fail to match on shellcode.
#
# for (2), this logic will need to be updated as the format is implemented.
logger.debug("unsupported file format: %s, will not guess OS", format_name)
return
def extract_arch() -> Iterator[Tuple[Feature, Address]]:
lang_id = currentProgram().getMetadata().get("Language ID") # type: ignore [name-defined] # noqa: F821
if "x86" in lang_id and "64" in lang_id:
yield Arch(ARCH_AMD64), NO_ADDRESS
elif "x86" in lang_id and "32" in lang_id:
yield Arch(ARCH_I386), NO_ADDRESS
elif "x86" not in lang_id:
logger.debug("unsupported architecture: non-32-bit nor non-64-bit intel")
return
else:
# we likely end up here:
# 1. handling a new architecture (e.g. aarch64)
#
# for (1), this logic will need to be updated as the format is implemented.
logger.debug("unsupported architecture: %s", lang_id)
return

View File

@@ -1,277 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
from typing import Dict, List, Iterator
import ghidra
import java.lang
from ghidra.program.model.lang import OperandType
from ghidra.program.model.block import BasicBlockModel, SimpleBlockIterator
from ghidra.program.model.symbol import SourceType, SymbolType
from ghidra.program.model.address import AddressSpace
import capa.features.extractors.helpers
from capa.features.common import THUNK_CHAIN_DEPTH_DELTA
from capa.features.address import AbsoluteVirtualAddress
from capa.features.extractors.base_extractor import BBHandle, InsnHandle, FunctionHandle
def ints_to_bytes(bytez: List[int]) -> bytes:
"""convert Java signed ints to Python bytes
args:
bytez: list of Java signed ints
"""
return bytes([b & 0xFF for b in bytez])
def find_byte_sequence(addr: ghidra.program.model.address.Address, seq: bytes) -> Iterator[int]:
"""yield all ea of a given byte sequence
args:
addr: start address
seq: bytes to search e.g. b"\x01\x03"
"""
seqstr = "".join([f"\\x{b:02x}" for b in seq])
eas = findBytes(addr, seqstr, java.lang.Integer.MAX_VALUE, 1) # type: ignore [name-defined] # noqa: F821
yield from eas
def get_bytes(addr: ghidra.program.model.address.Address, length: int) -> bytes:
"""yield length bytes at addr
args:
addr: Address to begin pull from
length: length of bytes to pull
"""
try:
return ints_to_bytes(getBytes(addr, length)) # type: ignore [name-defined] # noqa: F821
except RuntimeError:
return b""
def get_block_bytes(block: ghidra.program.model.mem.MemoryBlock) -> bytes:
"""yield all bytes in a given block
args:
block: MemoryBlock to pull from
"""
return get_bytes(block.getStart(), block.getSize())
def get_function_symbols():
"""yield all non-external function symbols"""
yield from currentProgram().getFunctionManager().getFunctionsNoStubs(True) # type: ignore [name-defined] # noqa: F821
def get_function_blocks(fh: FunctionHandle) -> Iterator[BBHandle]:
"""yield BBHandle for each bb in a given function"""
func: ghidra.program.database.function.FunctionDB = fh.inner
for bb in SimpleBlockIterator(BasicBlockModel(currentProgram()), func.getBody(), monitor()): # type: ignore [name-defined] # noqa: F821
yield BBHandle(address=AbsoluteVirtualAddress(bb.getMinAddress().getOffset()), inner=bb)
def get_insn_in_range(bbh: BBHandle) -> Iterator[InsnHandle]:
"""yield InshHandle for each insn in a given basicblock"""
for insn in currentProgram().getListing().getInstructions(bbh.inner, True): # type: ignore [name-defined] # noqa: F821
yield InsnHandle(address=AbsoluteVirtualAddress(insn.getAddress().getOffset()), inner=insn)
def get_file_imports() -> Dict[int, List[str]]:
"""get all import names & addrs"""
import_dict: Dict[int, List[str]] = {}
for f in currentProgram().getFunctionManager().getExternalFunctions(): # type: ignore [name-defined] # noqa: F821
for r in f.getSymbol().getReferences():
if r.getReferenceType().isData():
addr = r.getFromAddress().getOffset() # gets pointer to fake external addr
ex_loc = f.getExternalLocation().getAddress() # map external locations as well (offset into module files)
fstr = f.toString().split("::") # format: MODULE.dll::import / MODULE::Ordinal_* / <EXTERNAL>::import
if "Ordinal_" in fstr[1]:
fstr[1] = f"#{fstr[1].split('_')[1]}"
# <EXTERNAL> mostly shows up in ELF files, otherwise, strip '.dll' w/ [:-4]
fstr[0] = "*" if "<EXTERNAL>" in fstr[0] else fstr[0][:-4]
for name in capa.features.extractors.helpers.generate_symbols(fstr[0], fstr[1]):
import_dict.setdefault(addr, []).append(name)
if ex_loc:
import_dict.setdefault(ex_loc.getOffset(), []).append(name)
return import_dict
def get_file_externs() -> Dict[int, List[str]]:
"""
Gets function names & addresses of statically-linked library functions
Ghidra's external namespace is mostly reserved for dynamically-linked
imports. Statically-linked functions are part of the global namespace.
Filtering on the type, source, and namespace of the symbols yield more
statically-linked library functions.
Example: (PMA Lab 16-01.exe_) 7faafc7e4a5c736ebfee6abbbc812d80:0x407490
- __aulldiv
- Note: See Symbol Table labels
"""
extern_dict: Dict[int, List[str]] = {}
for sym in currentProgram().getSymbolTable().getAllSymbols(True): # type: ignore [name-defined] # noqa: F821
# .isExternal() misses more than this config for the function symbols
if sym.getSymbolType() == SymbolType.FUNCTION and sym.getSource() == SourceType.ANALYSIS and sym.isGlobal():
name = sym.getName() # starts to resolve names based on Ghidra's FidDB
if name.startswith("FID_conflict:"): # format: FID_conflict:<function-name>
name = name[13:]
extern_dict.setdefault(sym.getAddress().getOffset(), []).append(name)
if name.startswith("_"):
# some linkers may prefix linked routines with a `_` to avoid name collisions.
# extract features for both the mangled and un-mangled representations.
# e.g. `_fwrite` -> `fwrite`
# see: https://stackoverflow.com/a/2628384/87207
extern_dict.setdefault(sym.getAddress().getOffset(), []).append(name[1:])
return extern_dict
def map_fake_import_addrs() -> Dict[int, List[int]]:
"""
Map ghidra's fake import entrypoints to their
real addresses
Helps as many Ghidra Scripting API calls end up returning
these external (fake) addresses.
Undocumented but intended Ghidra behavior:
- Import entryPoint fields are stored in the 'EXTERNAL:' AddressSpace.
'getEntryPoint()' returns the entryPoint field, which is an offset
from the beginning of the assigned AddressSpace. In the case of externals,
they start from 1 and increment.
https://github.com/NationalSecurityAgency/ghidra/blob/26d4bd9104809747c21f2528cab8aba9aef9acd5/Ghidra/Features/Base/src/test.slow/java/ghidra/program/database/function/ExternalFunctionDBTest.java#L90
Example: (mimikatz.exe_) 5f66b82558ca92e54e77f216ef4c066c:0x473090
- 0x473090 -> PTR_CreateServiceW_00473090
- 'EXTERNAL:00000025' -> External Address (ghidra.program.model.address.SpecialAddress)
"""
fake_dict: Dict[int, List[int]] = {}
for f in currentProgram().getFunctionManager().getExternalFunctions(): # type: ignore [name-defined] # noqa: F821
for r in f.getSymbol().getReferences():
if r.getReferenceType().isData():
fake_dict.setdefault(f.getEntryPoint().getOffset(), []).append(r.getFromAddress().getOffset())
return fake_dict
def check_addr_for_api(
addr: ghidra.program.model.address.Address,
fakes: Dict[int, List[int]],
imports: Dict[int, List[str]],
externs: Dict[int, List[str]],
) -> bool:
offset = addr.getOffset()
fake = fakes.get(offset)
if fake:
return True
imp = imports.get(offset)
if imp:
return True
extern = externs.get(offset)
if extern:
return True
return False
def is_call_or_jmp(insn: ghidra.program.database.code.InstructionDB) -> bool:
return any(mnem in insn.getMnemonicString() for mnem in ["CALL", "J"]) # JMP, JNE, JNZ, etc
def is_sp_modified(insn: ghidra.program.database.code.InstructionDB) -> bool:
for i in range(insn.getNumOperands()):
if insn.getOperandType(i) == OperandType.REGISTER:
return "SP" in insn.getRegister(i).getName() and insn.getOperandRefType(i).isWrite()
return False
def is_stack_referenced(insn: ghidra.program.database.code.InstructionDB) -> bool:
"""generic catch-all for stack references"""
for i in range(insn.getNumOperands()):
if insn.getOperandType(i) == OperandType.REGISTER:
if "BP" in insn.getRegister(i).getName():
return True
else:
continue
return any(ref.isStackReference() for ref in insn.getReferencesFrom())
def is_zxor(insn: ghidra.program.database.code.InstructionDB) -> bool:
# assume XOR insn
# XOR's against the same operand zero out
ops = []
operands = []
for i in range(insn.getNumOperands()):
ops.append(insn.getOpObjects(i))
# Operands stored in a 2D array
for j in range(len(ops)):
for k in range(len(ops[j])):
operands.append(ops[j][k])
return all(n == operands[0] for n in operands)
def handle_thunk(addr: ghidra.program.model.address.Address):
"""Follow thunk chains down to a reasonable depth"""
ref = addr
for _ in range(THUNK_CHAIN_DEPTH_DELTA):
thunk_jmp = getInstructionAt(ref) # type: ignore [name-defined] # noqa: F821
if thunk_jmp and is_call_or_jmp(thunk_jmp):
if OperandType.isAddress(thunk_jmp.getOperandType(0)):
ref = thunk_jmp.getAddress(0)
else:
thunk_dat = getDataContaining(ref) # type: ignore [name-defined] # noqa: F821
if thunk_dat and thunk_dat.isDefined() and thunk_dat.isPointer():
ref = thunk_dat.getValue()
break # end of thunk chain reached
return ref
def dereference_ptr(insn: ghidra.program.database.code.InstructionDB):
addr_code = OperandType.ADDRESS | OperandType.CODE
to_deref = insn.getAddress(0)
dat = getDataContaining(to_deref) # type: ignore [name-defined] # noqa: F821
if insn.getOperandType(0) == addr_code:
thfunc = getFunctionContaining(to_deref) # type: ignore [name-defined] # noqa: F821
if thfunc and thfunc.isThunk():
return handle_thunk(to_deref)
else:
# if it doesn't poin to a thunk, it's usually a jmp to a label
return to_deref
if not dat:
return to_deref
if dat.isDefined() and dat.isPointer():
addr = dat.getValue()
# now we need to check the addr space to see if it is truly resolvable
# ghidra sometimes likes to hand us direct RAM addrs, which typically point
# to api calls that we can't actually resolve as such
if addr.getAddressSpace().getType() == AddressSpace.TYPE_RAM:
return to_deref
else:
return addr
else:
return to_deref

View File

@@ -1,521 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
from typing import Any, Dict, Tuple, Iterator
import ghidra
from ghidra.program.model.lang import OperandType
from ghidra.program.model.block import SimpleBlockModel
import capa.features.extractors.helpers
import capa.features.extractors.ghidra.helpers
from capa.features.insn import API, MAX_STRUCTURE_SIZE, Number, Offset, Mnemonic, OperandNumber, OperandOffset
from capa.features.common import MAX_BYTES_FEATURE_SIZE, Bytes, String, Feature, Characteristic
from capa.features.address import Address, AbsoluteVirtualAddress
from capa.features.extractors.base_extractor import BBHandle, InsnHandle, FunctionHandle
# security cookie checks may perform non-zeroing XORs, these are expected within a certain
# byte range within the first and returning basic blocks, this helps to reduce FP features
SECURITY_COOKIE_BYTES_DELTA = 0x40
def get_imports(ctx: Dict[str, Any]) -> Dict[int, Any]:
"""Populate the import cache for this context"""
if "imports_cache" not in ctx:
ctx["imports_cache"] = capa.features.extractors.ghidra.helpers.get_file_imports()
return ctx["imports_cache"]
def get_externs(ctx: Dict[str, Any]) -> Dict[int, Any]:
"""Populate the externs cache for this context"""
if "externs_cache" not in ctx:
ctx["externs_cache"] = capa.features.extractors.ghidra.helpers.get_file_externs()
return ctx["externs_cache"]
def get_fakes(ctx: Dict[str, Any]) -> Dict[int, Any]:
"""Populate the fake import addrs cache for this context"""
if "fakes_cache" not in ctx:
ctx["fakes_cache"] = capa.features.extractors.ghidra.helpers.map_fake_import_addrs()
return ctx["fakes_cache"]
def check_for_api_call(
insn, externs: Dict[int, Any], fakes: Dict[int, Any], imports: Dict[int, Any], imp_or_ex: bool
) -> Iterator[Any]:
"""check instruction for API call
params:
externs - external library functions cache
fakes - mapped fake import addresses cache
imports - imported functions cache
imp_or_ex - flag to check imports or externs
yields:
matched api calls
"""
info = ()
funcs = imports if imp_or_ex else externs
# assume only CALLs or JMPs are passed
ref_type = insn.getOperandType(0)
addr_data = OperandType.ADDRESS | OperandType.DATA # needs dereferencing
addr_code = OperandType.ADDRESS | OperandType.CODE # needs dereferencing
if OperandType.isRegister(ref_type):
if OperandType.isAddress(ref_type):
# If it's an address in a register, check the mapped fake addrs
# since they're dereferenced to their fake addrs
op_ref = insn.getAddress(0).getOffset()
ref = fakes.get(op_ref) # obtain the real addr
if not ref:
return
else:
return
elif ref_type in (addr_data, addr_code) or (OperandType.isIndirect(ref_type) and OperandType.isAddress(ref_type)):
# we must dereference and check if the addr is a pointer to an api function
addr_ref = capa.features.extractors.ghidra.helpers.dereference_ptr(insn)
if not capa.features.extractors.ghidra.helpers.check_addr_for_api(addr_ref, fakes, imports, externs):
return
ref = addr_ref.getOffset()
elif ref_type == OperandType.DYNAMIC | OperandType.ADDRESS or ref_type == OperandType.DYNAMIC:
return # cannot resolve dynamics statically
else:
# pure address does not need to get dereferenced/ handled
addr_ref = insn.getAddress(0)
if not addr_ref:
# If it returned null, it was an indirect
# that had no address reference.
# This check is faster than checking for (indirect and not address)
return
if not capa.features.extractors.ghidra.helpers.check_addr_for_api(addr_ref, fakes, imports, externs):
return
ref = addr_ref.getOffset()
if isinstance(ref, list): # ref from REG | ADDR
for r in ref:
info = funcs.get(r) # type: ignore
if info:
yield info
else:
info = funcs.get(ref) # type: ignore
if info:
yield info
def extract_insn_api_features(fh: FunctionHandle, bb: BBHandle, ih: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
insn: ghidra.program.database.code.InstructionDB = ih.inner
if not capa.features.extractors.ghidra.helpers.is_call_or_jmp(insn):
return
externs = get_externs(fh.ctx)
fakes = get_fakes(fh.ctx)
imports = get_imports(fh.ctx)
# check calls to imported functions
for api in check_for_api_call(insn, externs, fakes, imports, True):
for imp in api:
yield API(imp), ih.address
# check calls to extern functions
for api in check_for_api_call(insn, externs, fakes, imports, False):
for ext in api:
yield API(ext), ih.address
def extract_insn_number_features(fh: FunctionHandle, bb: BBHandle, ih: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
"""
parse instruction number features
example:
push 3136B0h ; dwControlCode
"""
insn: ghidra.program.database.code.InstructionDB = ih.inner
if insn.getMnemonicString().startswith("RET"):
# skip things like:
# .text:0042250E retn 8
return
if capa.features.extractors.ghidra.helpers.is_sp_modified(insn):
# skip things like:
# .text:00401145 add esp, 0Ch
return
for i in range(insn.getNumOperands()):
# Exceptions for LEA insn:
# invalid operand encoding, considered numbers instead of offsets
# see: mimikatz.exe_:0x4018C0
if insn.getOperandType(i) == OperandType.DYNAMIC and insn.getMnemonicString().startswith("LEA"):
# Additional check, avoid yielding "wide" values (ex. mimikatz.exe:0x471EE6 LEA EBX, [ECX + EAX*0x4])
op_objs = insn.getOpObjects(i)
if len(op_objs) == 3: # ECX, EAX, 0x4
continue
if isinstance(op_objs[-1], ghidra.program.model.scalar.Scalar):
const = op_objs[-1].getUnsignedValue()
addr = ih.address
yield Number(const), addr
yield OperandNumber(i, const), addr
elif not OperandType.isScalar(insn.getOperandType(i)):
# skip things like:
# references, void types
continue
else:
const = insn.getScalar(i).getUnsignedValue()
addr = ih.address
yield Number(const), addr
yield OperandNumber(i, const), addr
if insn.getMnemonicString().startswith("ADD") and 0 < const < MAX_STRUCTURE_SIZE:
# for pattern like:
#
# add eax, 0x10
#
# assume 0x10 is also an offset (imagine eax is a pointer).
yield Offset(const), addr
yield OperandOffset(i, const), addr
def extract_insn_offset_features(fh: FunctionHandle, bb: BBHandle, ih: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
"""
parse instruction structure offset features
example:
.text:0040112F cmp [esi+4], ebx
"""
insn: ghidra.program.database.code.InstructionDB = ih.inner
if insn.getMnemonicString().startswith("LEA"):
return
# ignore any stack references
if not capa.features.extractors.ghidra.helpers.is_stack_referenced(insn):
# Ghidra stores operands in 2D arrays if they contain offsets
for i in range(insn.getNumOperands()):
if insn.getOperandType(i) == OperandType.DYNAMIC: # e.g. [esi + 4]
# manual extraction, since the default api calls only work on the 1st dimension of the array
op_objs = insn.getOpObjects(i)
if isinstance(op_objs[-1], ghidra.program.model.scalar.Scalar):
op_off = op_objs[-1].getValue()
yield Offset(op_off), ih.address
yield OperandOffset(i, op_off), ih.address
else:
yield Offset(0), ih.address
yield OperandOffset(i, 0), ih.address
def extract_insn_bytes_features(fh: FunctionHandle, bb: BBHandle, ih: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
"""
parse referenced byte sequences
example:
push offset iid_004118d4_IShellLinkA ; riid
"""
insn: ghidra.program.database.code.InstructionDB = ih.inner
if capa.features.extractors.ghidra.helpers.is_call_or_jmp(insn):
return
ref = insn.getAddress() # init to insn addr
for i in range(insn.getNumOperands()):
if OperandType.isAddress(insn.getOperandType(i)):
ref = insn.getAddress(i) # pulls pointer if there is one
if ref != insn.getAddress(): # bail out if there's no pointer
ghidra_dat = getDataAt(ref) # type: ignore [name-defined] # noqa: F821
if (
ghidra_dat and not ghidra_dat.hasStringValue() and not ghidra_dat.isPointer()
): # avoid if the data itself is a pointer
extracted_bytes = capa.features.extractors.ghidra.helpers.get_bytes(ref, MAX_BYTES_FEATURE_SIZE)
if extracted_bytes and not capa.features.extractors.helpers.all_zeros(extracted_bytes):
# don't extract byte features for obvious strings
yield Bytes(extracted_bytes), ih.address
def extract_insn_string_features(fh: FunctionHandle, bb: BBHandle, ih: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
"""
parse instruction string features
example:
push offset aAcr ; "ACR > "
"""
insn: ghidra.program.database.code.InstructionDB = ih.inner
dyn_addr = OperandType.DYNAMIC | OperandType.ADDRESS
ref = insn.getAddress()
for i in range(insn.getNumOperands()):
if OperandType.isScalarAsAddress(insn.getOperandType(i)):
ref = insn.getAddress(i)
# strings are also referenced dynamically via pointers & arrays, so we need to deref them
if insn.getOperandType(i) == dyn_addr:
ref = insn.getAddress(i)
dat = getDataAt(ref) # type: ignore [name-defined] # noqa: F821
if dat and dat.isPointer():
ref = dat.getValue()
if ref != insn.getAddress():
ghidra_dat = getDataAt(ref) # type: ignore [name-defined] # noqa: F821
if ghidra_dat and ghidra_dat.hasStringValue():
yield String(ghidra_dat.getValue()), ih.address
def extract_insn_mnemonic_features(
fh: FunctionHandle, bb: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
"""parse instruction mnemonic features"""
insn: ghidra.program.database.code.InstructionDB = ih.inner
yield Mnemonic(insn.getMnemonicString().lower()), ih.address
def extract_insn_obfs_call_plus_5_characteristic_features(
fh: FunctionHandle, bb: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
"""
parse call $+5 instruction from the given instruction.
"""
insn: ghidra.program.database.code.InstructionDB = ih.inner
if not capa.features.extractors.ghidra.helpers.is_call_or_jmp(insn):
return
code_ref = OperandType.ADDRESS | OperandType.CODE
ref = insn.getAddress()
for i in range(insn.getNumOperands()):
if insn.getOperandType(i) == code_ref:
ref = insn.getAddress(i)
if insn.getAddress().add(5) == ref:
yield Characteristic("call $+5"), ih.address
def extract_insn_segment_access_features(
fh: FunctionHandle, bb: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
"""parse instruction fs or gs access"""
insn: ghidra.program.database.code.InstructionDB = ih.inner
insn_str = insn.toString()
if "FS:" in insn_str:
yield Characteristic("fs access"), ih.address
if "GS:" in insn_str:
yield Characteristic("gs access"), ih.address
def extract_insn_peb_access_characteristic_features(
fh: FunctionHandle, bb: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
"""parse instruction peb access
fs:[0x30] on x86, gs:[0x60] on x64
"""
insn: ghidra.program.database.code.InstructionDB = ih.inner
insn_str = insn.toString()
if insn_str.startswith(("PUSH", "MOV")):
if "FS:[0x30]" in insn_str or "GS:[0x60]" in insn_str:
yield Characteristic("peb access"), ih.address
def extract_insn_cross_section_cflow(
fh: FunctionHandle, bb: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
"""inspect the instruction for a CALL or JMP that crosses section boundaries"""
insn: ghidra.program.database.code.InstructionDB = ih.inner
if not capa.features.extractors.ghidra.helpers.is_call_or_jmp(insn):
return
externs = get_externs(fh.ctx)
fakes = get_fakes(fh.ctx)
imports = get_imports(fh.ctx)
# OperandType to dereference
addr_data = OperandType.ADDRESS | OperandType.DATA
addr_code = OperandType.ADDRESS | OperandType.CODE
ref_type = insn.getOperandType(0)
# both OperandType flags must be present
# bail on REGISTER alone
if OperandType.isRegister(ref_type):
if OperandType.isAddress(ref_type):
ref = insn.getAddress(0) # Ghidra dereferences REG | ADDR
if capa.features.extractors.ghidra.helpers.check_addr_for_api(ref, fakes, imports, externs):
return
else:
return
elif ref_type in (addr_data, addr_code) or (OperandType.isIndirect(ref_type) and OperandType.isAddress(ref_type)):
# we must dereference and check if the addr is a pointer to an api function
ref = capa.features.extractors.ghidra.helpers.dereference_ptr(insn)
if capa.features.extractors.ghidra.helpers.check_addr_for_api(ref, fakes, imports, externs):
return
elif ref_type == OperandType.DYNAMIC | OperandType.ADDRESS or ref_type == OperandType.DYNAMIC:
return # cannot resolve dynamics statically
else:
# pure address does not need to get dereferenced/ handled
ref = insn.getAddress(0)
if not ref:
# If it returned null, it was an indirect
# that had no address reference.
# This check is faster than checking for (indirect and not address)
return
if capa.features.extractors.ghidra.helpers.check_addr_for_api(ref, fakes, imports, externs):
return
this_mem_block = getMemoryBlock(insn.getAddress()) # type: ignore [name-defined] # noqa: F821
ref_block = getMemoryBlock(ref) # type: ignore [name-defined] # noqa: F821
if ref_block != this_mem_block:
yield Characteristic("cross section flow"), ih.address
def extract_function_calls_from(
fh: FunctionHandle,
bb: BBHandle,
ih: InsnHandle,
) -> Iterator[Tuple[Feature, Address]]:
"""extract functions calls from features
most relevant at the function scope, however, its most efficient to extract at the instruction scope
"""
insn: ghidra.program.database.code.InstructionDB = ih.inner
if insn.getMnemonicString().startswith("CALL"):
# This method of "dereferencing" addresses/ pointers
# is not as robust as methods in other functions,
# but works just fine for this one
reference = 0
for ref in insn.getReferencesFrom():
addr = ref.getToAddress()
# avoid returning fake addrs
if not addr.isExternalAddress():
reference = addr.getOffset()
# if a reference is < 0, then ghidra pulled an offset from a DYNAMIC | ADDR (usually a stackvar)
# these cannot be resolved to actual addrs
if reference > 0:
yield Characteristic("calls from"), AbsoluteVirtualAddress(reference)
def extract_function_indirect_call_characteristic_features(
fh: FunctionHandle,
bb: BBHandle,
ih: InsnHandle,
) -> Iterator[Tuple[Feature, Address]]:
"""extract indirect function calls (e.g., call eax or call dword ptr [edx+4])
does not include calls like => call ds:dword_ABD4974
most relevant at the function or basic block scope;
however, its most efficient to extract at the instruction scope
"""
insn: ghidra.program.database.code.InstructionDB = ih.inner
if insn.getMnemonicString().startswith("CALL"):
if OperandType.isRegister(insn.getOperandType(0)):
yield Characteristic("indirect call"), ih.address
if OperandType.isIndirect(insn.getOperandType(0)):
yield Characteristic("indirect call"), ih.address
def check_nzxor_security_cookie_delta(
fh: ghidra.program.database.function.FunctionDB, insn: ghidra.program.database.code.InstructionDB
):
"""Get the function containing the insn
Get the last block of the function that contains the insn
Check the bb containing the insn
Check the last bb of the function containing the insn
"""
model = SimpleBlockModel(currentProgram()) # type: ignore [name-defined] # noqa: F821
insn_addr = insn.getAddress()
func_asv = fh.getBody()
first_addr = func_asv.getMinAddress()
last_addr = func_asv.getMaxAddress()
if model.getFirstCodeBlockContaining(
first_addr, monitor() # type: ignore [name-defined] # noqa: F821
) == model.getFirstCodeBlockContaining(
last_addr, monitor() # type: ignore [name-defined] # noqa: F821
):
if insn_addr < first_addr.add(SECURITY_COOKIE_BYTES_DELTA):
return True
else:
return insn_addr > last_addr.add(SECURITY_COOKIE_BYTES_DELTA * -1)
else:
return False
def extract_insn_nzxor_characteristic_features(
fh: FunctionHandle,
bb: BBHandle,
ih: InsnHandle,
) -> Iterator[Tuple[Feature, Address]]:
f: ghidra.program.database.function.FunctionDB = fh.inner
insn: ghidra.program.database.code.InstructionDB = ih.inner
if "XOR" not in insn.getMnemonicString():
return
if capa.features.extractors.ghidra.helpers.is_stack_referenced(insn):
return
if capa.features.extractors.ghidra.helpers.is_zxor(insn):
return
if check_nzxor_security_cookie_delta(f, insn):
return
yield Characteristic("nzxor"), ih.address
def extract_features(
fh: FunctionHandle,
bb: BBHandle,
insn: InsnHandle,
) -> Iterator[Tuple[Feature, Address]]:
for insn_handler in INSTRUCTION_HANDLERS:
for feature, addr in insn_handler(fh, bb, insn):
yield feature, addr
INSTRUCTION_HANDLERS = (
extract_insn_api_features,
extract_insn_number_features,
extract_insn_bytes_features,
extract_insn_string_features,
extract_insn_offset_features,
extract_insn_nzxor_characteristic_features,
extract_insn_mnemonic_features,
extract_insn_obfs_call_plus_5_characteristic_features,
extract_insn_peb_access_characteristic_features,
extract_insn_cross_section_cflow,
extract_insn_segment_access_features,
extract_function_calls_from,
extract_function_indirect_call_characteristic_features,
)
def main():
""" """
features = []
from capa.features.extractors.ghidra.extractor import GhidraFeatureExtractor
for fh in GhidraFeatureExtractor().get_functions():
for bb in capa.features.extractors.ghidra.helpers.get_function_blocks(fh):
for insn in capa.features.extractors.ghidra.helpers.get_insn_in_range(bb):
features.extend(list(extract_features(fh, bb, insn)))
import pprint
pprint.pprint(features) # noqa: T203
if __name__ == "__main__":
main()

View File

@@ -1,4 +1,4 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
@@ -6,18 +6,23 @@
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import struct
import sys
import builtins
from typing import Tuple, Iterator
from capa.features.file import Import
from capa.features.insn import API
MIN_STACKSTRING_LEN = 8
def xor_static(data: bytes, i: int) -> bytes:
return bytes(c ^ i for c in data)
def xor_static(data, i):
if sys.version_info >= (3, 0):
return bytes(c ^ i for c in data)
else:
return "".join(chr(ord(c) ^ i) for c in data)
def is_aw_function(symbol: str) -> bool:
def is_aw_function(symbol):
"""
is the given function name an A/W function?
these are variants of functions that, on Windows, accept either a narrow or wide string.
@@ -29,10 +34,11 @@ def is_aw_function(symbol: str) -> bool:
if symbol[-1] not in ("A", "W"):
return False
return True
# second to last character should be lowercase letter
return "a" <= symbol[-2] <= "z" or "0" <= symbol[-2] <= "9"
def is_ordinal(symbol: str) -> bool:
def is_ordinal(symbol):
"""
is the given symbol an ordinal that is prefixed by "#"?
"""
@@ -41,7 +47,7 @@ def is_ordinal(symbol: str) -> bool:
return False
def generate_symbols(dll: str, symbol: str) -> Iterator[str]:
def generate_symbols(dll, symbol):
"""
for a given dll and symbol name, generate variants.
we over-generate features to make matching easier.
@@ -51,11 +57,8 @@ def generate_symbols(dll: str, symbol: str) -> Iterator[str]:
- CreateFileA
- CreateFile
"""
# normalize dll name
dll = dll.lower()
# kernel32.CreateFileA
yield f"{dll}.{symbol}"
yield "%s.%s" % (dll, symbol)
if not is_ordinal(symbol):
# CreateFileA
@@ -63,35 +66,18 @@ def generate_symbols(dll: str, symbol: str) -> Iterator[str]:
if is_aw_function(symbol):
# kernel32.CreateFile
yield f"{dll}.{symbol[:-1]}"
yield "%s.%s" % (dll, symbol[:-1])
if not is_ordinal(symbol):
# CreateFile
yield symbol[:-1]
def reformat_forwarded_export_name(forwarded_name: str) -> str:
"""
a forwarded export has a DLL name/path an symbol name.
we want the former to be lowercase, and the latter to be verbatim.
"""
# use rpartition so we can split on separator between dll and name.
# the dll name can be a full path, like in the case of
# ef64d6d7c34250af8e21a10feb931c9b
# which i assume means the path can have embedded periods.
# so we don't want the first period, we want the last.
forwarded_dll, _, forwarded_symbol = forwarded_name.rpartition(".")
forwarded_dll = forwarded_dll.lower()
return f"{forwarded_dll}.{forwarded_symbol}"
def all_zeros(bytez: bytes) -> bool:
def all_zeros(bytez):
return all(b == 0 for b in builtins.bytes(bytez))
def twos_complement(val: int, bits: int) -> int:
def twos_complement(val, bits):
"""
compute the 2's complement of int value val
@@ -104,48 +90,3 @@ def twos_complement(val: int, bits: int) -> int:
else:
# return positive value as is
return val
def carve_pe(pbytes: bytes, offset: int = 0) -> Iterator[Tuple[int, int]]:
"""
Generate (offset, key) tuples of embedded PEs
Based on the version from vivisect:
https://github.com/vivisect/vivisect/blob/7be4037b1cecc4551b397f840405a1fc606f9b53/PE/carve.py#L19
And its IDA adaptation:
capa/features/extractors/ida/file.py
"""
mz_xor = [
(
xor_static(b"MZ", key),
xor_static(b"PE", key),
key,
)
for key in range(256)
]
pblen = len(pbytes)
todo = [(pbytes.find(mzx, offset), mzx, pex, key) for mzx, pex, key in mz_xor]
todo = [(off, mzx, pex, key) for (off, mzx, pex, key) in todo if off != -1]
while len(todo):
off, mzx, pex, key = todo.pop()
# The MZ header has one field we will check
# e_lfanew is at 0x3c
e_lfanew = off + 0x3C
if pblen < (e_lfanew + 4):
continue
newoff = struct.unpack("<I", xor_static(pbytes[e_lfanew : e_lfanew + 4], key))[0]
nextres = pbytes.find(mzx, off + 1)
if nextres != -1:
todo.append((nextres, mzx, pex, key))
peoff = off + newoff
if pblen < (peoff + 2):
continue
if pbytes[peoff : peoff + 2] == pex:
yield (off, key)

View File

@@ -0,0 +1,93 @@
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import sys
import types
import idaapi
import capa.features.extractors.ida.file
import capa.features.extractors.ida.insn
import capa.features.extractors.ida.function
import capa.features.extractors.ida.basicblock
from capa.features.extractors import FeatureExtractor
def get_ea(self):
""" """
if isinstance(self, (idaapi.BasicBlock, idaapi.func_t)):
return self.start_ea
if isinstance(self, idaapi.insn_t):
return self.ea
raise TypeError
def add_ea_int_cast(o):
"""
dynamically add a cast-to-int (`__int__`) method to the given object
that returns the value of the `.ea` property.
this bit of skullduggery lets use cast viv-utils objects as ints.
the correct way of doing this is to update viv-utils (or subclass the objects here).
"""
if sys.version_info[0] >= 3:
setattr(o, "__int__", types.MethodType(get_ea, o))
else:
setattr(o, "__int__", types.MethodType(get_ea, o, type(o)))
return o
class IdaFeatureExtractor(FeatureExtractor):
def __init__(self):
super(IdaFeatureExtractor, self).__init__()
def get_base_address(self):
return idaapi.get_imagebase()
def extract_file_features(self):
for (feature, ea) in capa.features.extractors.ida.file.extract_features():
yield feature, ea
def get_functions(self):
import capa.features.extractors.ida.helpers as ida_helpers
# data structure shared across functions yielded here.
# useful for caching analysis relevant across a single workspace.
ctx = {}
# ignore library functions and thunk functions as identified by IDA
for f in ida_helpers.get_functions(skip_thunks=True, skip_libs=True):
setattr(f, "ctx", ctx)
yield add_ea_int_cast(f)
@staticmethod
def get_function(ea):
f = idaapi.get_func(ea)
setattr(f, "ctx", {})
return add_ea_int_cast(f)
def extract_function_features(self, f):
for (feature, ea) in capa.features.extractors.ida.function.extract_features(f):
yield feature, ea
def get_basic_blocks(self, f):
for bb in capa.features.extractors.ida.helpers.get_function_blocks(f):
yield add_ea_int_cast(bb)
def extract_basic_block_features(self, f, bb):
for (feature, ea) in capa.features.extractors.ida.basicblock.extract_features(f, bb):
yield feature, ea
def get_instructions(self, f, bb):
import capa.features.extractors.ida.helpers as ida_helpers
for insn in ida_helpers.get_instructions_in_range(bb.start_ea, bb.end_ea):
yield add_ea_int_cast(insn)
def extract_insn_features(self, f, bb, insn):
for (feature, ea) in capa.features.extractors.ida.insn.extract_features(f, bb, insn):
yield feature, ea

View File

@@ -1,4 +1,4 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
@@ -6,23 +6,25 @@
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import sys
import string
import struct
from typing import Tuple, Iterator
import idaapi
import capa.features.extractors.ida.helpers
from capa.features.common import Feature, Characteristic
from capa.features.address import Address
from capa.features import Characteristic
from capa.features.basicblock import BasicBlock
from capa.features.extractors.ida import helpers
from capa.features.extractors.helpers import MIN_STACKSTRING_LEN
from capa.features.extractors.base_extractor import BBHandle, FunctionHandle
def get_printable_len(op: idaapi.op_t) -> int:
"""Return string length if all operand bytes are ascii or utf16-le printable"""
def get_printable_len(op):
"""Return string length if all operand bytes are ascii or utf16-le printable
args:
op (IDA op_t)
"""
op_val = capa.features.extractors.ida.helpers.mask_op_val(op)
if op.dtype == idaapi.dt_byte:
@@ -34,14 +36,21 @@ def get_printable_len(op: idaapi.op_t) -> int:
elif op.dtype == idaapi.dt_qword:
chars = struct.pack("<Q", op_val)
else:
raise ValueError(f"Unhandled operand data type 0x{op.dtype:x}.")
raise ValueError("Unhandled operand data type 0x%x." % op.dtype)
def is_printable_ascii(chars_: bytes):
return all(c < 127 and chr(c) in string.printable for c in chars_)
def is_printable_ascii(chars):
if sys.version_info[0] >= 3:
return all(c < 127 and chr(c) in string.printable for c in chars)
else:
return all(ord(c) < 127 and c in string.printable for c in chars)
def is_printable_utf16le(chars_: bytes):
if all(c == 0x00 for c in chars_[1::2]):
return is_printable_ascii(chars_[::2])
def is_printable_utf16le(chars):
if sys.version_info[0] >= 3:
if all(c == 0x00 for c in chars[1::2]):
return is_printable_ascii(chars[::2])
else:
if all(c == "\x00" for c in chars[1::2]):
return is_printable_ascii(chars[::2])
if is_printable_ascii(chars):
return idaapi.get_dtype_size(op.dtype)
@@ -52,8 +61,12 @@ def get_printable_len(op: idaapi.op_t) -> int:
return 0
def is_mov_imm_to_stack(insn: idaapi.insn_t) -> bool:
"""verify instruction moves immediate onto stack"""
def is_mov_imm_to_stack(insn):
"""verify instruction moves immediate onto stack
args:
insn (IDA insn_t)
"""
if insn.Op2.type != idaapi.o_imm:
return False
@@ -66,10 +79,14 @@ def is_mov_imm_to_stack(insn: idaapi.insn_t) -> bool:
return True
def bb_contains_stackstring(f: idaapi.func_t, bb: idaapi.BasicBlock) -> bool:
def bb_contains_stackstring(f, bb):
"""check basic block for stackstring indicators
true if basic block contains enough moves of constant bytes to the stack
args:
f (IDA func_t)
bb (IDA BasicBlock)
"""
count = 0
for insn in capa.features.extractors.ida.helpers.get_instructions_in_range(bb.start_ea, bb.end_ea):
@@ -80,27 +97,57 @@ def bb_contains_stackstring(f: idaapi.func_t, bb: idaapi.BasicBlock) -> bool:
return False
def extract_bb_stackstring(fh: FunctionHandle, bbh: BBHandle) -> Iterator[Tuple[Feature, Address]]:
"""extract stackstring indicators from basic block"""
if bb_contains_stackstring(fh.inner, bbh.inner):
yield Characteristic("stack string"), bbh.address
def extract_bb_stackstring(f, bb):
"""extract stackstring indicators from basic block
args:
f (IDA func_t)
bb (IDA BasicBlock)
"""
if bb_contains_stackstring(f, bb):
yield Characteristic("stack string"), bb.start_ea
def extract_bb_tight_loop(fh: FunctionHandle, bbh: BBHandle) -> Iterator[Tuple[Feature, Address]]:
"""extract tight loop indicators from a basic block"""
if capa.features.extractors.ida.helpers.is_basic_block_tight_loop(bbh.inner):
yield Characteristic("tight loop"), bbh.address
def extract_bb_tight_loop(f, bb):
"""extract tight loop indicators from a basic block
args:
f (IDA func_t)
bb (IDA BasicBlock)
"""
if capa.features.extractors.ida.helpers.is_basic_block_tight_loop(bb):
yield Characteristic("tight loop"), bb.start_ea
def extract_features(fh: FunctionHandle, bbh: BBHandle) -> Iterator[Tuple[Feature, Address]]:
"""extract basic block features"""
def extract_features(f, bb):
"""extract basic block features
args:
f (IDA func_t)
bb (IDA BasicBlock)
"""
for bb_handler in BASIC_BLOCK_HANDLERS:
for feature, addr in bb_handler(fh, bbh):
yield feature, addr
yield BasicBlock(), bbh.address
for (feature, ea) in bb_handler(f, bb):
yield feature, ea
yield BasicBlock(), bb.start_ea
BASIC_BLOCK_HANDLERS = (
extract_bb_tight_loop,
extract_bb_stackstring,
)
def main():
features = []
for f in helpers.get_functions(skip_thunks=True, skip_libs=True):
for bb in idaapi.FlowChart(f, flags=idaapi.FC_PREDS):
features.extend(list(extract_features(f, bb)))
import pprint
pprint.pprint(features)
if __name__ == "__main__":
main()

View File

@@ -1,71 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
from typing import List, Tuple, Iterator
import idaapi
import capa.ida.helpers
import capa.features.extractors.elf
import capa.features.extractors.ida.file
import capa.features.extractors.ida.insn
import capa.features.extractors.ida.global_
import capa.features.extractors.ida.function
import capa.features.extractors.ida.basicblock
from capa.features.common import Feature
from capa.features.address import Address, AbsoluteVirtualAddress
from capa.features.extractors.base_extractor import BBHandle, InsnHandle, FunctionHandle, FeatureExtractor
class IdaFeatureExtractor(FeatureExtractor):
def __init__(self):
super().__init__()
self.global_features: List[Tuple[Feature, Address]] = []
self.global_features.extend(capa.features.extractors.ida.file.extract_file_format())
self.global_features.extend(capa.features.extractors.ida.global_.extract_os())
self.global_features.extend(capa.features.extractors.ida.global_.extract_arch())
def get_base_address(self):
return AbsoluteVirtualAddress(idaapi.get_imagebase())
def extract_global_features(self):
yield from self.global_features
def extract_file_features(self):
yield from capa.features.extractors.ida.file.extract_features()
def get_functions(self) -> Iterator[FunctionHandle]:
import capa.features.extractors.ida.helpers as ida_helpers
# ignore library functions and thunk functions as identified by IDA
yield from ida_helpers.get_functions(skip_thunks=True, skip_libs=True)
@staticmethod
def get_function(ea: int) -> FunctionHandle:
f = idaapi.get_func(ea)
return FunctionHandle(address=AbsoluteVirtualAddress(f.start_ea), inner=f)
def extract_function_features(self, fh: FunctionHandle) -> Iterator[Tuple[Feature, Address]]:
yield from capa.features.extractors.ida.function.extract_features(fh)
def get_basic_blocks(self, fh: FunctionHandle) -> Iterator[BBHandle]:
import capa.features.extractors.ida.helpers as ida_helpers
for bb in ida_helpers.get_function_blocks(fh.inner):
yield BBHandle(address=AbsoluteVirtualAddress(bb.start_ea), inner=bb)
def extract_basic_block_features(self, fh: FunctionHandle, bbh: BBHandle) -> Iterator[Tuple[Feature, Address]]:
yield from capa.features.extractors.ida.basicblock.extract_features(fh, bbh)
def get_instructions(self, fh: FunctionHandle, bbh: BBHandle) -> Iterator[InsnHandle]:
import capa.features.extractors.ida.helpers as ida_helpers
for insn in ida_helpers.get_instructions_in_range(bbh.inner.start_ea, bbh.inner.end_ea):
yield InsnHandle(address=AbsoluteVirtualAddress(insn.ea), inner=insn)
def extract_insn_features(self, fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle):
yield from capa.features.extractors.ida.insn.extract_features(fh, bbh, ih)

View File

@@ -1,4 +1,4 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
@@ -7,29 +7,26 @@
# See the License for the specific language governing permissions and limitations under the License.
import struct
from typing import Tuple, Iterator
import idc
import idaapi
import idautils
import ida_entry
import capa.features.extractors.common
import capa.features.extractors.helpers
import capa.features.extractors.strings
import capa.features.extractors.ida.helpers
from capa.features.file import Export, Import, Section, FunctionName
from capa.features.common import FORMAT_PE, FORMAT_ELF, Format, String, Feature, Characteristic
from capa.features.address import NO_ADDRESS, Address, FileOffsetAddress, AbsoluteVirtualAddress
MAX_OFFSET_PE_AFTER_MZ = 0x200
from capa.features import String, Characteristic
from capa.features.file import Export, Import, Section
def check_segment_for_pe(seg: idaapi.segment_t) -> Iterator[Tuple[int, int]]:
def check_segment_for_pe(seg):
"""check segment for embedded PE
adapted for IDA from:
https://github.com/vivisect/vivisect/blob/91e8419a861f49779f18316f155311967e696836/PE/carve.py#L25
https://github.com/vivisect/vivisect/blob/7be4037b1cecc4551b397f840405a1fc606f9b53/PE/carve.py#L19
args:
seg (IDA segment_t)
"""
seg_max = seg.end_ea
mz_xor = [
@@ -42,15 +39,14 @@ def check_segment_for_pe(seg: idaapi.segment_t) -> Iterator[Tuple[int, int]]:
]
todo = []
for mzx, pex, i in mz_xor:
# find all segment offsets containing XOR'd "MZ" bytes
for (mzx, pex, i) in mz_xor:
for off in capa.features.extractors.ida.helpers.find_byte_sequence(seg.start_ea, seg.end_ea, mzx):
todo.append((off, mzx, pex, i))
while len(todo):
off, mzx, pex, i = todo.pop()
# MZ header has one field we will check e_lfanew is at 0x3c
# The MZ header has one field we will check e_lfanew is at 0x3c
e_lfanew = off + 0x3C
if seg_max < (e_lfanew + 4):
@@ -58,19 +54,18 @@ def check_segment_for_pe(seg: idaapi.segment_t) -> Iterator[Tuple[int, int]]:
newoff = struct.unpack("<I", capa.features.extractors.helpers.xor_static(idc.get_bytes(e_lfanew, 4), i))[0]
# assume XOR'd "PE" bytes exist within threshold
if newoff > MAX_OFFSET_PE_AFTER_MZ:
continue
peoff = off + newoff
if seg_max < (peoff + 2):
continue
if idc.get_bytes(peoff, 2) == pex:
yield off, i
yield (off, i)
for nextres in capa.features.extractors.ida.helpers.find_byte_sequence(off + 1, seg.end_ea, mzx):
todo.append((nextres, mzx, pex, i))
def extract_file_embedded_pe() -> Iterator[Tuple[Feature, Address]]:
def extract_file_embedded_pe():
"""extract embedded PE features
IDA must load resource sections for this to be complete
@@ -78,23 +73,17 @@ def extract_file_embedded_pe() -> Iterator[Tuple[Feature, Address]]:
- Check 'Load resource sections' when opening binary in IDA manually
"""
for seg in capa.features.extractors.ida.helpers.get_segments(skip_header_segments=True):
for ea, _ in check_segment_for_pe(seg):
yield Characteristic("embedded pe"), FileOffsetAddress(ea)
for (ea, _) in check_segment_for_pe(seg):
yield Characteristic("embedded pe"), ea
def extract_file_export_names() -> Iterator[Tuple[Feature, Address]]:
"""extract function exports"""
for _, ordinal, ea, name in idautils.Entries():
forwarded_name = ida_entry.get_entry_forwarder(ordinal)
if forwarded_name is None:
yield Export(name), AbsoluteVirtualAddress(ea)
else:
forwarded_name = capa.features.extractors.helpers.reformat_forwarded_export_name(forwarded_name)
yield Export(forwarded_name), AbsoluteVirtualAddress(ea)
yield Characteristic("forwarded export"), AbsoluteVirtualAddress(ea)
def extract_file_export_names():
""" extract function exports """
for (_, _, ea, name) in idautils.Entries():
yield Export(name), ea
def extract_file_import_names() -> Iterator[Tuple[Feature, Address]]:
def extract_file_import_names():
"""extract function imports
1. imports by ordinal:
@@ -105,32 +94,28 @@ def extract_file_import_names() -> Iterator[Tuple[Feature, Address]]:
- modulename.importname
- importname
"""
for ea, info in capa.features.extractors.ida.helpers.get_file_imports().items():
addr = AbsoluteVirtualAddress(ea)
for (ea, info) in capa.features.extractors.ida.helpers.get_file_imports().items():
if info[1] and info[2]:
# e.g. in mimikatz: ('cabinet', 'FCIAddFile', 11L)
# extract by name here and by ordinal below
for name in capa.features.extractors.helpers.generate_symbols(info[0], info[1]):
yield Import(name), addr
yield Import(name), ea
dll = info[0]
symbol = f"#{info[2]}"
symbol = "#%d" % (info[2])
elif info[1]:
dll = info[0]
symbol = info[1]
elif info[2]:
dll = info[0]
symbol = f"#{info[2]}"
symbol = "#%d" % (info[2])
else:
continue
for name in capa.features.extractors.helpers.generate_symbols(dll, symbol):
yield Import(name), addr
for ea, info in capa.features.extractors.ida.helpers.get_file_externs().items():
yield Import(info[1]), AbsoluteVirtualAddress(ea)
yield Import(name), ea
def extract_file_section_names() -> Iterator[Tuple[Feature, Address]]:
def extract_file_section_names():
"""extract section names
IDA must load resource sections for this to be complete
@@ -138,10 +123,10 @@ def extract_file_section_names() -> Iterator[Tuple[Feature, Address]]:
- Check 'Load resource sections' when opening binary in IDA manually
"""
for seg in capa.features.extractors.ida.helpers.get_segments(skip_header_segments=True):
yield Section(idaapi.get_segm_name(seg)), AbsoluteVirtualAddress(seg.start_ea)
yield Section(idaapi.get_segm_name(seg)), seg.start_ea
def extract_file_strings() -> Iterator[Tuple[Feature, Address]]:
def extract_file_strings():
"""extract ASCII and UTF-16 LE strings
IDA must load resource sections for this to be complete
@@ -151,50 +136,18 @@ def extract_file_strings() -> Iterator[Tuple[Feature, Address]]:
for seg in capa.features.extractors.ida.helpers.get_segments():
seg_buff = capa.features.extractors.ida.helpers.get_segment_buffer(seg)
# differing to common string extractor factor in segment offset here
for s in capa.features.extractors.strings.extract_ascii_strings(seg_buff):
yield String(s.s), FileOffsetAddress(seg.start_ea + s.offset)
yield String(s.s), (seg.start_ea + s.offset)
for s in capa.features.extractors.strings.extract_unicode_strings(seg_buff):
yield String(s.s), FileOffsetAddress(seg.start_ea + s.offset)
yield String(s.s), (seg.start_ea + s.offset)
def extract_file_function_names() -> Iterator[Tuple[Feature, Address]]:
"""
extract the names of statically-linked library functions.
"""
for ea in idautils.Functions():
addr = AbsoluteVirtualAddress(ea)
if idaapi.get_func(ea).flags & idaapi.FUNC_LIB:
name = idaapi.get_name(ea)
yield FunctionName(name), addr
if name.startswith("_"):
# some linkers may prefix linked routines with a `_` to avoid name collisions.
# extract features for both the mangled and un-mangled representations.
# e.g. `_fwrite` -> `fwrite`
# see: https://stackoverflow.com/a/2628384/87207
yield FunctionName(name[1:]), addr
def extract_file_format() -> Iterator[Tuple[Feature, Address]]:
file_info = idaapi.get_inf_structure()
if file_info.filetype in (idaapi.f_PE, idaapi.f_COFF):
yield Format(FORMAT_PE), NO_ADDRESS
elif file_info.filetype == idaapi.f_ELF:
yield Format(FORMAT_ELF), NO_ADDRESS
elif file_info.filetype == idaapi.f_BIN:
# no file type to return when processing a binary file, but we want to continue processing
return
else:
raise NotImplementedError(f"unexpected file format: {file_info.filetype}")
def extract_features() -> Iterator[Tuple[Feature, Address]]:
"""extract file features"""
def extract_features():
""" extract file features """
for file_handler in FILE_HANDLERS:
for feature, addr in file_handler():
yield feature, addr
for feature, va in file_handler():
yield feature, va
FILE_HANDLERS = (
@@ -203,6 +156,15 @@ FILE_HANDLERS = (
extract_file_strings,
extract_file_section_names,
extract_file_embedded_pe,
extract_file_function_names,
extract_file_format,
)
def main():
""" """
import pprint
pprint.pprint(list(extract_features()))
if __name__ == "__main__":
main()

View File

@@ -1,31 +1,35 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
from typing import Tuple, Iterator
import idaapi
import idautils
import capa.features.extractors.ida.helpers
from capa.features.common import Feature, Characteristic
from capa.features.address import Address, AbsoluteVirtualAddress
from capa.features import Characteristic
from capa.features.extractors import loops
from capa.features.extractors.base_extractor import FunctionHandle
def extract_function_calls_to(fh: FunctionHandle):
"""extract callers to a function"""
for ea in idautils.CodeRefsTo(fh.inner.start_ea, True):
yield Characteristic("calls to"), AbsoluteVirtualAddress(ea)
def extract_function_calls_to(f):
"""extract callers to a function
args:
f (IDA func_t)
"""
for ea in idautils.CodeRefsTo(f.start_ea, True):
yield Characteristic("calls to"), ea
def extract_function_loop(fh: FunctionHandle):
"""extract loop indicators from a function"""
f: idaapi.func_t = fh.inner
def extract_function_loop(f):
"""extract loop indicators from a function
args:
f (IDA func_t)
"""
edges = []
# construct control flow graph
@@ -34,19 +38,43 @@ def extract_function_loop(fh: FunctionHandle):
edges.append((bb.start_ea, succ.start_ea))
if loops.has_loop(edges):
yield Characteristic("loop"), fh.address
yield Characteristic("loop"), f.start_ea
def extract_recursive_call(fh: FunctionHandle):
"""extract recursive function call"""
if capa.features.extractors.ida.helpers.is_function_recursive(fh.inner):
yield Characteristic("recursive call"), fh.address
def extract_recursive_call(f):
"""extract recursive function call
args:
f (IDA func_t)
"""
if capa.features.extractors.ida.helpers.is_function_recursive(f):
yield Characteristic("recursive call"), f.start_ea
def extract_features(fh: FunctionHandle) -> Iterator[Tuple[Feature, Address]]:
def extract_features(f):
"""extract function features
arg:
f (IDA func_t)
"""
for func_handler in FUNCTION_HANDLERS:
for feature, addr in func_handler(fh):
yield feature, addr
for (feature, ea) in func_handler(f):
yield feature, ea
FUNCTION_HANDLERS = (extract_function_calls_to, extract_function_loop, extract_recursive_call)
def main():
""" """
features = []
for f in capa.features.extractors.ida.get_functions(skip_thunks=True, skip_libs=True):
features.extend(list(extract_features(f)))
import pprint
pprint.pprint(features)
if __name__ == "__main__":
main()

View File

@@ -1,65 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import logging
import contextlib
from typing import Tuple, Iterator
import idaapi
import ida_loader
import capa.ida.helpers
import capa.features.extractors.elf
from capa.features.common import OS, ARCH_I386, ARCH_AMD64, OS_WINDOWS, Arch, Feature
from capa.features.address import NO_ADDRESS, Address
logger = logging.getLogger(__name__)
def extract_os() -> Iterator[Tuple[Feature, Address]]:
format_name: str = ida_loader.get_file_type_name()
if "PE" in format_name:
yield OS(OS_WINDOWS), NO_ADDRESS
elif "ELF" in format_name:
with contextlib.closing(capa.ida.helpers.IDAIO()) as f:
os = capa.features.extractors.elf.detect_elf_os(f)
yield OS(os), NO_ADDRESS
else:
# we likely end up here:
# 1. handling shellcode, or
# 2. handling a new file format (e.g. macho)
#
# for (1) we can't do much - its shellcode and all bets are off.
# we could maybe accept a further CLI argument to specify the OS,
# but i think this would be rarely used.
# rules that rely on OS conditions will fail to match on shellcode.
#
# for (2), this logic will need to be updated as the format is implemented.
logger.debug("unsupported file format: %s, will not guess OS", format_name)
return
def extract_arch() -> Iterator[Tuple[Feature, Address]]:
info: idaapi.idainfo = idaapi.get_inf_structure()
if info.procname == "metapc" and info.is_64bit():
yield Arch(ARCH_AMD64), NO_ADDRESS
elif info.procname == "metapc" and info.is_32bit():
yield Arch(ARCH_I386), NO_ADDRESS
elif info.procname == "metapc":
logger.debug("unsupported architecture: non-32-bit nor non-64-bit intel")
return
else:
# we likely end up here:
# 1. handling a new architecture (e.g. aarch64)
#
# for (1), this logic will need to be updated as the format is implemented.
logger.debug("unsupported architecture: %s", info.procname)
return

View File

@@ -1,24 +1,21 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import functools
from typing import Any, Dict, Tuple, Iterator, Optional
import sys
import string
import idc
import idaapi
import idautils
import ida_bytes
import ida_segment
from capa.features.address import AbsoluteVirtualAddress
from capa.features.extractors.base_extractor import FunctionHandle
def find_byte_sequence(start: int, end: int, seq: bytes) -> Iterator[int]:
def find_byte_sequence(start, end, seq):
"""yield all ea of a given byte sequence
args:
@@ -26,33 +23,36 @@ def find_byte_sequence(start: int, end: int, seq: bytes) -> Iterator[int]:
end: max virtual address
seq: bytes to search e.g. b"\x01\x03"
"""
seqstr = " ".join([f"{b:02x}" for b in seq])
if sys.version_info[0] >= 3:
seq = " ".join(["%02x" % b for b in seq])
else:
seq = " ".join(["%02x" % ord(b) for b in seq])
while True:
# TODO(mike-hunhoff): find_binary is deprecated. Please use ida_bytes.bin_search() instead.
# https://github.com/mandiant/capa/issues/1606
ea = idaapi.find_binary(start, end, seqstr, 0, idaapi.SEARCH_DOWN)
ea = idaapi.find_binary(start, end, seq, 0, idaapi.SEARCH_DOWN)
if ea == idaapi.BADADDR:
break
start = ea + 1
yield ea
def get_functions(
start: Optional[int] = None, end: Optional[int] = None, skip_thunks: bool = False, skip_libs: bool = False
) -> Iterator[FunctionHandle]:
def get_functions(start=None, end=None, skip_thunks=False, skip_libs=False):
"""get functions, range optional
args:
start: min virtual address
end: max virtual address
ret:
yield func_t*
"""
for ea in idautils.Functions(start=start, end=end):
f = idaapi.get_func(ea)
if not (skip_thunks and (f.flags & idaapi.FUNC_THUNK) or skip_libs and (f.flags & idaapi.FUNC_LIB)):
yield FunctionHandle(address=AbsoluteVirtualAddress(ea), inner=f)
yield f
def get_segments(skip_header_segments=False) -> Iterator[idaapi.segment_t]:
def get_segments(skip_header_segments=False):
"""get list of segments (sections) in the binary image
args:
@@ -64,7 +64,7 @@ def get_segments(skip_header_segments=False) -> Iterator[idaapi.segment_t]:
yield seg
def get_segment_buffer(seg: idaapi.segment_t) -> bytes:
def get_segment_buffer(seg):
"""return bytes stored in a given segment
decrease buffer size until IDA is able to read bytes from the segment
@@ -82,22 +82,9 @@ def get_segment_buffer(seg: idaapi.segment_t) -> bytes:
return buff if buff else b""
def inspect_import(imports, library, ea, function, ordinal):
if function and function.startswith("__imp_"):
# handle mangled PE imports
function = function[len("__imp_") :]
if function and "@@" in function:
# handle mangled ELF imports, like "fopen@@glibc_2.2.5"
function, _, _ = function.partition("@@")
imports[ea] = (library.lower(), function, ordinal)
return True
def get_file_imports() -> Dict[int, Tuple[str, str, int]]:
"""get file imports"""
imports: Dict[int, Tuple[str, str, int]] = {}
def get_file_imports():
""" get file imports """
imports = {}
for idx in range(idaapi.get_import_module_qty()):
library = idaapi.get_import_module_name(idx)
@@ -105,38 +92,26 @@ def get_file_imports() -> Dict[int, Tuple[str, str, int]]:
if not library:
continue
# IDA uses section names for the library of ELF imports, like ".dynsym".
# These are not useful to us, we may need to expand this list over time
# TODO(williballenthin): find all section names used by IDA
# https://github.com/mandiant/capa/issues/1419
if library == ".dynsym":
library = ""
def inspect_import(ea, function, ordinal):
if function and function.startswith("__imp_"):
# handle mangled names starting
function = function[len("__imp_") :]
imports[ea] = (library.lower(), function, ordinal)
return True
cb = functools.partial(inspect_import, imports, library)
idaapi.enum_import_names(idx, cb)
idaapi.enum_import_names(idx, inspect_import)
return imports
def get_file_externs() -> Dict[int, Tuple[str, str, int]]:
externs = {}
for seg in get_segments(skip_header_segments=True):
if seg.type != ida_segment.SEG_XTRN:
continue
for ea in idautils.Functions(seg.start_ea, seg.end_ea):
externs[ea] = ("", idaapi.get_func_name(ea), -1)
return externs
def get_instructions_in_range(start: int, end: int) -> Iterator[idaapi.insn_t]:
def get_instructions_in_range(start, end):
"""yield instructions in range
args:
start: virtual address (inclusive)
end: virtual address (exclusive)
yield:
(insn_t*)
"""
for head in idautils.Heads(start, end):
insn = idautils.DecodeInstruction(head)
@@ -144,8 +119,8 @@ def get_instructions_in_range(start: int, end: int) -> Iterator[idaapi.insn_t]:
yield insn
def is_operand_equal(op1: idaapi.op_t, op2: idaapi.op_t) -> bool:
"""compare two IDA op_t"""
def is_operand_equal(op1, op2):
""" compare two IDA op_t """
if op1.flags != op2.flags:
return False
@@ -170,8 +145,8 @@ def is_operand_equal(op1: idaapi.op_t, op2: idaapi.op_t) -> bool:
return True
def is_basic_block_equal(bb1: idaapi.BasicBlock, bb2: idaapi.BasicBlock) -> bool:
"""compare two IDA BasicBlock"""
def is_basic_block_equal(bb1, bb2):
""" compare two IDA BasicBlock """
if bb1.start_ea != bb2.start_ea:
return False
@@ -184,12 +159,12 @@ def is_basic_block_equal(bb1: idaapi.BasicBlock, bb2: idaapi.BasicBlock) -> bool
return True
def basic_block_size(bb: idaapi.BasicBlock) -> int:
"""calculate size of basic block"""
def basic_block_size(bb):
""" calculate size of basic block """
return bb.end_ea - bb.start_ea
def read_bytes_at(ea: int, count: int) -> bytes:
def read_bytes_at(ea, count):
""" """
# check if byte has a value, see get_wide_byte doc
if not idc.is_loaded(ea):
@@ -202,10 +177,10 @@ def read_bytes_at(ea: int, count: int) -> bytes:
return idc.get_bytes(ea, count)
def find_string_at(ea: int, min_: int = 4) -> str:
"""check if ASCII string exists at a given virtual address"""
def find_string_at(ea, min=4):
""" check if ASCII string exists at a given virtual address """
found = idaapi.get_strlit_contents(ea, -1, idaapi.STRTYPE_C)
if found and len(found) >= min_:
if found and len(found) > min:
try:
found = found.decode("ascii")
# hacky check for IDA bug; get_strlit_contents also reads Unicode as
@@ -219,7 +194,7 @@ def find_string_at(ea: int, min_: int = 4) -> str:
return ""
def get_op_phrase_info(op: idaapi.op_t) -> Dict:
def get_op_phrase_info(op):
"""parse phrase features from operand
Pretty much dup of sark's implementation:
@@ -229,8 +204,7 @@ def get_op_phrase_info(op: idaapi.op_t) -> Dict:
return {}
scale = 1 << ((op.specflag2 & 0xC0) >> 6)
# IDA ea_t may be 32- or 64-bit; we assume displacement can only be 32-bit
offset = op.addr & 0xFFFFFFFF
offset = op.addr
if op.specflag1 == 0:
index = None
@@ -257,45 +231,47 @@ def get_op_phrase_info(op: idaapi.op_t) -> Dict:
return {"base": base, "index": index, "scale": scale, "offset": offset}
def is_op_write(insn: idaapi.insn_t, op: idaapi.op_t) -> bool:
"""Check if an operand is written to (destination operand)"""
def is_op_write(insn, op):
""" Check if an operand is written to (destination operand) """
return idaapi.has_cf_chg(insn.get_canon_feature(), op.n)
def is_op_read(insn: idaapi.insn_t, op: idaapi.op_t) -> bool:
"""Check if an operand is read from (source operand)"""
def is_op_read(insn, op):
""" Check if an operand is read from (source operand) """
return idaapi.has_cf_use(insn.get_canon_feature(), op.n)
def is_op_offset(insn: idaapi.insn_t, op: idaapi.op_t) -> bool:
"""Check is an operand has been marked as an offset (by auto-analysis or manually)"""
def is_op_offset(insn, op):
""" Check is an operand has been marked as an offset (by auto-analysis or manually) """
flags = idaapi.get_flags(insn.ea)
return ida_bytes.is_off(flags, op.n)
def is_sp_modified(insn: idaapi.insn_t) -> bool:
"""determine if instruction modifies SP, ESP, RSP"""
return any(
op.reg == idautils.procregs.sp.reg and is_op_write(insn, op)
for op in get_insn_ops(insn, target_ops=(idaapi.o_reg,))
)
def is_sp_modified(insn):
""" determine if instruction modifies SP, ESP, RSP """
for op in get_insn_ops(insn, target_ops=(idaapi.o_reg,)):
if op.reg == idautils.procregs.sp.reg and is_op_write(insn, op):
# register is stack and written
return True
return False
def is_bp_modified(insn: idaapi.insn_t) -> bool:
"""check if instruction modifies BP, EBP, RBP"""
return any(
op.reg == idautils.procregs.bp.reg and is_op_write(insn, op)
for op in get_insn_ops(insn, target_ops=(idaapi.o_reg,))
)
def is_bp_modified(insn):
""" check if instruction modifies BP, EBP, RBP """
for op in get_insn_ops(insn, target_ops=(idaapi.o_reg,)):
if op.reg == idautils.procregs.bp.reg and is_op_write(insn, op):
# register is base and written
return True
return False
def is_frame_register(reg: int) -> bool:
"""check if register is sp or bp"""
def is_frame_register(reg):
""" check if register is sp or bp """
return reg in (idautils.procregs.sp.reg, idautils.procregs.bp.reg)
def get_insn_ops(insn: idaapi.insn_t, target_ops: Optional[Tuple[Any]] = None) -> idaapi.op_t:
"""yield op_t for instruction, filter on type if specified"""
def get_insn_ops(insn, target_ops=()):
""" yield op_t for instruction, filter on type if specified """
for op in insn.ops:
if op.type == idaapi.o_void:
# avoid looping all 6 ops if only subset exists
@@ -305,12 +281,12 @@ def get_insn_ops(insn: idaapi.insn_t, target_ops: Optional[Tuple[Any]] = None) -
yield op
def is_op_stack_var(ea: int, index: int) -> bool:
"""check if operand is a stack variable"""
def is_op_stack_var(ea, index):
""" check if operand is a stack variable """
return idaapi.is_stkvar(idaapi.get_flags(ea), index)
def mask_op_val(op: idaapi.op_t) -> int:
def mask_op_val(op):
"""mask value by data type
necessary due to a bug in AMD64
@@ -330,15 +306,26 @@ def mask_op_val(op: idaapi.op_t) -> int:
return masks.get(op.dtype, op.value) & op.value
def is_function_recursive(f: idaapi.func_t) -> bool:
"""check if function is recursive"""
return any(f.contains(ref) for ref in idautils.CodeRefsTo(f.start_ea, True))
def is_function_recursive(f):
"""check if function is recursive
args:
f (IDA func_t)
"""
for ref in idautils.CodeRefsTo(f.start_ea, True):
if f.contains(ref):
return True
return False
def is_basic_block_tight_loop(bb: idaapi.BasicBlock) -> bool:
def is_basic_block_tight_loop(bb):
"""check basic block loops to self
true if last instruction in basic block branches to basic block start
args:
f (IDA func_t)
bb (IDA BasicBlock)
"""
bb_end = idc.prev_head(bb.end_ea)
if bb.start_ea < bb_end:
@@ -348,8 +335,8 @@ def is_basic_block_tight_loop(bb: idaapi.BasicBlock) -> bool:
return False
def find_data_reference_from_insn(insn: idaapi.insn_t, max_depth: int = 10) -> int:
"""search for data reference from instruction, return address of instruction if no reference exists"""
def find_data_reference_from_insn(insn, max_depth=10):
""" search for data reference from instruction, return address of instruction if no reference exists """
depth = 0
ea = insn.ea
@@ -378,17 +365,19 @@ def find_data_reference_from_insn(insn: idaapi.insn_t, max_depth: int = 10) -> i
return ea
def get_function_blocks(f: idaapi.func_t) -> Iterator[idaapi.BasicBlock]:
"""yield basic blocks contained in specified function"""
def get_function_blocks(f):
"""yield basic blocks contained in specified function
args:
f (IDA func_t)
yield:
block (IDA BasicBlock)
"""
# leverage idaapi.FC_NOEXT flag to ignore useless external blocks referenced by the function
yield from idaapi.FlowChart(f, flags=(idaapi.FC_PREDS | idaapi.FC_NOEXT))
for block in idaapi.FlowChart(f, flags=(idaapi.FC_PREDS | idaapi.FC_NOEXT)):
yield block
def is_basic_block_return(bb: idaapi.BasicBlock) -> bool:
"""check if basic block is return block"""
def is_basic_block_return(bb):
""" check if basic block is return block """
return bb.type == idaapi.fcb_ret
def has_sib(oper: idaapi.op_t) -> bool:
# via: https://reverseengineering.stackexchange.com/a/14300
return oper.specflag1 == 1

View File

@@ -1,11 +1,10 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
from typing import Any, Dict, Tuple, Iterator
import idc
import idaapi
@@ -13,30 +12,51 @@ import idautils
import capa.features.extractors.helpers
import capa.features.extractors.ida.helpers
from capa.features.insn import API, MAX_STRUCTURE_SIZE, Number, Offset, Mnemonic, OperandNumber, OperandOffset
from capa.features.common import MAX_BYTES_FEATURE_SIZE, THUNK_CHAIN_DEPTH_DELTA, Bytes, String, Feature, Characteristic
from capa.features.address import Address, AbsoluteVirtualAddress
from capa.features.extractors.base_extractor import BBHandle, InsnHandle, FunctionHandle
from capa.features import (
ARCH_X32,
ARCH_X64,
MAX_BYTES_FEATURE_SIZE,
THUNK_CHAIN_DEPTH_DELTA,
Bytes,
String,
Characteristic,
)
from capa.features.insn import API, Number, Offset, Mnemonic
# security cookie checks may perform non-zeroing XORs, these are expected within a certain
# byte range within the first and returning basic blocks, this helps to reduce FP features
SECURITY_COOKIE_BYTES_DELTA = 0x40
def get_imports(ctx: Dict[str, Any]) -> Dict[int, Any]:
def get_arch(ctx):
"""
fetch the ARCH_* constant for the currently open workspace.
via Tamir Bahar/@tmr232
https://reverseengineering.stackexchange.com/a/11398/17194
"""
if "arch" not in ctx:
info = idaapi.get_inf_structure()
if info.is_64bit():
ctx["arch"] = ARCH_X64
elif info.is_32bit():
ctx["arch"] = ARCH_X32
else:
raise ValueError("unexpected architecture")
return ctx["arch"]
def get_imports(ctx):
if "imports_cache" not in ctx:
ctx["imports_cache"] = capa.features.extractors.ida.helpers.get_file_imports()
return ctx["imports_cache"]
def get_externs(ctx: Dict[str, Any]) -> Dict[int, Any]:
if "externs_cache" not in ctx:
ctx["externs_cache"] = capa.features.extractors.ida.helpers.get_file_externs()
return ctx["externs_cache"]
def check_for_api_call(ctx, insn):
""" check instruction for API call """
if not insn.get_canon_mnem() in ("call", "jmp"):
return
def check_for_api_call(insn: idaapi.insn_t, funcs: Dict[int, Any]) -> Iterator[Any]:
"""check instruction for API call"""
info = ()
ref = insn.ea
@@ -52,7 +72,7 @@ def check_for_api_call(insn: idaapi.insn_t, funcs: Dict[int, Any]) -> Iterator[A
except IndexError:
break
info = funcs.get(ref, ())
info = get_imports(ctx).get(ref, ())
if info:
break
@@ -61,64 +81,37 @@ def check_for_api_call(insn: idaapi.insn_t, funcs: Dict[int, Any]) -> Iterator[A
break
if info:
yield info
yield "%s.%s" % (info[0], info[1])
def extract_insn_api_features(fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
"""
parse instruction API features
def extract_insn_api_features(f, bb, insn):
"""parse instruction API features
args:
f (IDA func_t)
bb (IDA BasicBlock)
insn (IDA insn_t)
example:
call dword [0x00473038]
call dword [0x00473038]
"""
insn: idaapi.insn_t = ih.inner
if insn.get_canon_mnem() not in ("call", "jmp"):
return
# check calls to imported functions
for api in check_for_api_call(insn, get_imports(fh.ctx)):
# tuple (<module>, <function>, <ordinal>)
for name in capa.features.extractors.helpers.generate_symbols(api[0], api[1]):
yield API(name), ih.address
# check calls to extern functions
for api in check_for_api_call(insn, get_externs(fh.ctx)):
# tuple (<module>, <function>, <ordinal>)
yield API(api[1]), ih.address
# extract IDA/FLIRT recognized API functions
targets = tuple(idautils.CodeRefsFrom(insn.ea, False))
if not targets:
return
target = targets[0]
target_func = idaapi.get_func(target)
if not target_func or target_func.start_ea != target:
# not a function (start)
return
if target_func.flags & idaapi.FUNC_LIB:
name = idaapi.get_name(target_func.start_ea)
yield API(name), ih.address
if name.startswith("_"):
# some linkers may prefix linked routines with a `_` to avoid name collisions.
# extract features for both the mangled and un-mangled representations.
# e.g. `_fwrite` -> `fwrite`
# see: https://stackoverflow.com/a/2628384/87207
yield API(name[1:]), ih.address
for api in check_for_api_call(f.ctx, insn):
dll, _, symbol = api.rpartition(".")
for name in capa.features.extractors.helpers.generate_symbols(dll, symbol):
yield API(name), insn.ea
def extract_insn_number_features(
fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
"""
parse instruction number features
def extract_insn_number_features(f, bb, insn):
"""parse instruction number features
args:
f (IDA func_t)
bb (IDA BasicBlock)
insn (IDA insn_t)
example:
push 3136B0h ; dwControlCode
"""
insn: idaapi.insn_t = ih.inner
if idaapi.is_ret_insn(insn):
# skip things like:
# .text:0042250E retn 8
@@ -129,11 +122,7 @@ def extract_insn_number_features(
# .text:00401145 add esp, 0Ch
return
for i, op in enumerate(insn.ops):
if op.type == idaapi.o_void:
break
if op.type not in (idaapi.o_imm, idaapi.o_mem):
continue
for op in capa.features.extractors.ida.helpers.get_insn_ops(insn, target_ops=(idaapi.o_imm, idaapi.o_mem)):
# skip things like:
# .text:00401100 shr eax, offset loc_C
if capa.features.extractors.ida.helpers.is_op_offset(insn, op):
@@ -144,27 +133,21 @@ def extract_insn_number_features(
else:
const = op.addr
yield Number(const), ih.address
yield OperandNumber(i, const), ih.address
if insn.itype == idaapi.NN_add and 0 < const < MAX_STRUCTURE_SIZE and op.type == idaapi.o_imm:
# for pattern like:
#
# add eax, 0x10
#
# assume 0x10 is also an offset (imagine eax is a pointer).
yield Offset(const), ih.address
yield OperandOffset(i, const), ih.address
yield Number(const), insn.ea
yield Number(const, arch=get_arch(f.ctx)), insn.ea
def extract_insn_bytes_features(fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
"""
parse referenced byte sequences
def extract_insn_bytes_features(f, bb, insn):
"""parse referenced byte sequences
args:
f (IDA func_t)
bb (IDA BasicBlock)
insn (IDA insn_t)
example:
push offset iid_004118d4_IShellLinkA ; riid
"""
insn: idaapi.insn_t = ih.inner
if idaapi.is_call_insn(insn):
return
@@ -172,54 +155,43 @@ def extract_insn_bytes_features(fh: FunctionHandle, bbh: BBHandle, ih: InsnHandl
if ref != insn.ea:
extracted_bytes = capa.features.extractors.ida.helpers.read_bytes_at(ref, MAX_BYTES_FEATURE_SIZE)
if extracted_bytes and not capa.features.extractors.helpers.all_zeros(extracted_bytes):
if not capa.features.extractors.ida.helpers.find_string_at(ref):
# don't extract byte features for obvious strings
yield Bytes(extracted_bytes), ih.address
yield Bytes(extracted_bytes), insn.ea
def extract_insn_string_features(
fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
"""
parse instruction string features
def extract_insn_string_features(f, bb, insn):
"""parse instruction string features
args:
f (IDA func_t)
bb (IDA BasicBlock)
insn (IDA insn_t)
example:
push offset aAcr ; "ACR > "
"""
insn: idaapi.insn_t = ih.inner
ref = capa.features.extractors.ida.helpers.find_data_reference_from_insn(insn)
if ref != insn.ea:
found = capa.features.extractors.ida.helpers.find_string_at(ref)
if found:
yield String(found), ih.address
yield String(found), insn.ea
def extract_insn_offset_features(
fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
"""
parse instruction structure offset features
def extract_insn_offset_features(f, bb, insn):
"""parse instruction structure offset features
args:
f (IDA func_t)
bb (IDA BasicBlock)
insn (IDA insn_t)
example:
.text:0040112F cmp [esi+4], ebx
"""
insn: idaapi.insn_t = ih.inner
for i, op in enumerate(insn.ops):
if op.type == idaapi.o_void:
break
if op.type not in (idaapi.o_phrase, idaapi.o_displ):
continue
for op in capa.features.extractors.ida.helpers.get_insn_ops(insn, target_ops=(idaapi.o_phrase, idaapi.o_displ)):
if capa.features.extractors.ida.helpers.is_op_stack_var(insn.ea, op.n):
continue
p_info = capa.features.extractors.ida.helpers.get_op_phrase_info(op)
op_off = p_info.get("offset")
if op_off is None:
continue
op_off = p_info.get("offset", 0)
if idaapi.is_mapped(op_off):
# Ignore:
# mov esi, dword_1005B148[esi]
@@ -230,32 +202,12 @@ def extract_insn_offset_features(
# https://stackoverflow.com/questions/31853189/x86-64-assembly-why-displacement-not-64-bits
op_off = capa.features.extractors.helpers.twos_complement(op_off, 32)
yield Offset(op_off), ih.address
yield OperandOffset(i, op_off), ih.address
if (
insn.itype == idaapi.NN_lea
and i == 1
# o_displ is used for both:
# [eax+1]
# [eax+ebx+2]
and op.type == idaapi.o_displ
# but the SIB is only present for [eax+ebx+2]
# which we don't want
and not capa.features.extractors.ida.helpers.has_sib(op)
):
# for pattern like:
#
# lea eax, [ebx + 1]
#
# assume 1 is also an offset (imagine ebx is a zero register).
yield Number(op_off), ih.address
yield OperandNumber(i, op_off), ih.address
yield Offset(op_off), insn.ea
yield Offset(op_off, arch=get_arch(f.ctx)), insn.ea
def contains_stack_cookie_keywords(s: str) -> bool:
"""
check if string contains stack cookie keywords
def contains_stack_cookie_keywords(s):
"""check if string contains stack cookie keywords
Examples:
xor ecx, ebp ; StackCookie
@@ -269,7 +221,7 @@ def contains_stack_cookie_keywords(s: str) -> bool:
return any(keyword in s for keyword in ("stack", "security"))
def bb_stack_cookie_registers(bb: idaapi.BasicBlock) -> Iterator[int]:
def bb_stack_cookie_registers(bb):
"""scan basic block for stack cookie operations
yield registers ids that may have been used for stack cookie operations
@@ -303,8 +255,8 @@ def bb_stack_cookie_registers(bb: idaapi.BasicBlock) -> Iterator[int]:
yield op.reg
def is_nzxor_stack_cookie_delta(f: idaapi.func_t, bb: idaapi.BasicBlock, insn: idaapi.insn_t) -> bool:
"""check if nzxor exists within stack cookie delta"""
def is_nzxor_stack_cookie_delta(f, bb, insn):
""" check if nzxor exists within stack cookie delta """
# security cookie check should use SP or BP
if not capa.features.extractors.ida.helpers.is_frame_register(insn.Op2.reg):
return False
@@ -326,8 +278,8 @@ def is_nzxor_stack_cookie_delta(f: idaapi.func_t, bb: idaapi.BasicBlock, insn: i
return False
def is_nzxor_stack_cookie(f: idaapi.func_t, bb: idaapi.BasicBlock, insn: idaapi.insn_t) -> bool:
"""check if nzxor is related to stack cookie"""
def is_nzxor_stack_cookie(f, bb, insn):
""" check if nzxor is related to stack cookie """
if contains_stack_cookie_keywords(idaapi.get_cmt(insn.ea, False)):
# Example:
# xor ecx, ebp ; StackCookie
@@ -343,49 +295,37 @@ def is_nzxor_stack_cookie(f: idaapi.func_t, bb: idaapi.BasicBlock, insn: idaapi.
return False
def extract_insn_nzxor_characteristic_features(
fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
"""
parse instruction non-zeroing XOR instruction
ignore expected non-zeroing XORs, e.g. security cookies
"""
insn: idaapi.insn_t = ih.inner
def extract_insn_nzxor_characteristic_features(f, bb, insn):
"""parse instruction non-zeroing XOR instruction
ignore expected non-zeroing XORs, e.g. security cookies
args:
f (IDA func_t)
bb (IDA BasicBlock)
insn (IDA insn_t)
"""
if insn.itype not in (idaapi.NN_xor, idaapi.NN_xorpd, idaapi.NN_xorps, idaapi.NN_pxor):
return
if capa.features.extractors.ida.helpers.is_operand_equal(insn.Op1, insn.Op2):
return
if is_nzxor_stack_cookie(fh.inner, bbh.inner, insn):
if is_nzxor_stack_cookie(f, bb, insn):
return
yield Characteristic("nzxor"), ih.address
yield Characteristic("nzxor"), insn.ea
def extract_insn_mnemonic_features(
fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
"""parse instruction mnemonic features"""
yield Mnemonic(idc.print_insn_mnem(ih.inner.ea)), ih.address
def extract_insn_mnemonic_features(f, bb, insn):
"""parse instruction mnemonic features
def extract_insn_obfs_call_plus_5_characteristic_features(
fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
args:
f (IDA func_t)
bb (IDA BasicBlock)
insn (IDA insn_t)
"""
parse call $+5 instruction from the given instruction.
"""
insn: idaapi.insn_t = ih.inner
if not idaapi.is_call_insn(insn):
return
if insn.ea + 5 == idc.get_operand_value(insn.ea, 0):
yield Characteristic("call $+5"), ih.address
yield Mnemonic(insn.get_canon_mnem()), insn.ea
def extract_insn_peb_access_characteristic_features(
fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
def extract_insn_peb_access_characteristic_features(f, bb, insn):
"""parse instruction peb access
fs:[0x30] on x86, gs:[0x60] on x64
@@ -393,61 +333,51 @@ def extract_insn_peb_access_characteristic_features(
TODO:
IDA should be able to do this..
"""
insn: idaapi.insn_t = ih.inner
if insn.itype not in (idaapi.NN_push, idaapi.NN_mov):
return
if all(op.type != idaapi.o_mem for op in insn.ops):
if all(map(lambda op: op.type != idaapi.o_mem, insn.ops)):
# try to optimize for only memory references
return
disasm = idc.GetDisasm(insn.ea)
if " fs:30h" in disasm or " gs:60h" in disasm:
# TODO(mike-hunhoff): use proper IDA API for fetching segment access
# scanning the disassembly text is a hack.
# https://github.com/mandiant/capa/issues/1605
yield Characteristic("peb access"), ih.address
# TODO: replace above with proper IDA
yield Characteristic("peb access"), insn.ea
def extract_insn_segment_access_features(
fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
def extract_insn_segment_access_features(f, bb, insn):
"""parse instruction fs or gs access
TODO:
IDA should be able to do this...
"""
insn: idaapi.insn_t = ih.inner
if all(op.type != idaapi.o_mem for op in insn.ops):
if all(map(lambda op: op.type != idaapi.o_mem, insn.ops)):
# try to optimize for only memory references
return
disasm = idc.GetDisasm(insn.ea)
if " fs:" in disasm:
# TODO(mike-hunhoff): use proper IDA API for fetching segment access
# scanning the disassembly text is a hack.
# https://github.com/mandiant/capa/issues/1605
yield Characteristic("fs access"), ih.address
# TODO: replace above with proper IDA
yield Characteristic("fs access"), insn.ea
if " gs:" in disasm:
# TODO(mike-hunhoff): use proper IDA API for fetching segment access
# scanning the disassembly text is a hack.
# https://github.com/mandiant/capa/issues/1605
yield Characteristic("gs access"), ih.address
# TODO: replace above with proper IDA
yield Characteristic("gs access"), insn.ea
def extract_insn_cross_section_cflow(
fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
"""inspect the instruction for a CALL or JMP that crosses section boundaries"""
insn: idaapi.insn_t = ih.inner
def extract_insn_cross_section_cflow(f, bb, insn):
"""inspect the instruction for a CALL or JMP that crosses section boundaries
args:
f (IDA func_t)
bb (IDA BasicBlock)
insn (IDA insn_t)
"""
for ref in idautils.CodeRefsFrom(insn.ea, False):
if ref in get_imports(fh.ctx):
if ref in get_imports(f.ctx).keys():
# ignore API calls
continue
if not idaapi.getseg(ref):
@@ -455,40 +385,50 @@ def extract_insn_cross_section_cflow(
continue
if idaapi.getseg(ref) == idaapi.getseg(insn.ea):
continue
yield Characteristic("cross section flow"), ih.address
yield Characteristic("cross section flow"), insn.ea
def extract_function_calls_from(fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
def extract_function_calls_from(f, bb, insn):
"""extract functions calls from features
most relevant at the function scope, however, its most efficient to extract at the instruction scope
"""
insn: idaapi.insn_t = ih.inner
args:
f (IDA func_t)
bb (IDA BasicBlock)
insn (IDA insn_t)
"""
if idaapi.is_call_insn(insn):
for ref in idautils.CodeRefsFrom(insn.ea, False):
yield Characteristic("calls from"), AbsoluteVirtualAddress(ref)
yield Characteristic("calls from"), ref
def extract_function_indirect_call_characteristic_features(
fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
def extract_function_indirect_call_characteristic_features(f, bb, insn):
"""extract indirect function calls (e.g., call eax or call dword ptr [edx+4])
does not include calls like => call ds:dword_ABD4974
most relevant at the function or basic block scope;
however, its most efficient to extract at the instruction scope
args:
f (IDA func_t)
bb (IDA BasicBlock)
insn (IDA insn_t)
"""
insn: idaapi.insn_t = ih.inner
if idaapi.is_call_insn(insn) and idc.get_operand_type(insn.ea, 0) in (idc.o_reg, idc.o_phrase, idc.o_displ):
yield Characteristic("indirect call"), ih.address
yield Characteristic("indirect call"), insn.ea
def extract_features(f: FunctionHandle, bbh: BBHandle, insn: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
"""extract instruction features"""
def extract_features(f, bb, insn):
"""extract instruction features
args:
f (IDA func_t)
bb (IDA BasicBlock)
insn (IDA insn_t)
"""
for inst_handler in INSTRUCTION_HANDLERS:
for feature, ea in inst_handler(f, bbh, insn):
for (feature, ea) in inst_handler(f, bb, insn):
yield feature, ea
@@ -500,10 +440,26 @@ INSTRUCTION_HANDLERS = (
extract_insn_offset_features,
extract_insn_nzxor_characteristic_features,
extract_insn_mnemonic_features,
extract_insn_obfs_call_plus_5_characteristic_features,
extract_insn_peb_access_characteristic_features,
extract_insn_cross_section_cflow,
extract_insn_segment_access_features,
extract_function_calls_from,
extract_function_indirect_call_characteristic_features,
)
def main():
""" """
features = []
for f in capa.features.extractors.ida.helpers.get_functions(skip_thunks=True, skip_libs=True):
for bb in idaapi.FlowChart(f, flags=idaapi.FC_PREDS):
for insn in capa.features.extractors.ida.helpers.get_instructions_in_range(bb.start_ea, bb.end_ea):
features.extend(list(extract_features(f, bb, insn)))
import pprint
pprint.pprint(features)
if __name__ == "__main__":
main()

View File

@@ -1,4 +1,4 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
@@ -6,7 +6,7 @@
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import networkx
from networkx import nx
from networkx.algorithms.components import strongly_connected_components
@@ -20,6 +20,6 @@ def has_loop(edges, threshold=2):
returns:
bool
"""
g = networkx.DiGraph()
g = nx.DiGraph()
g.add_edges_from(edges)
return any(len(comp) >= threshold for comp in strongly_connected_components(g))

View File

@@ -1,79 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
from typing import Dict, List, Tuple
from dataclasses import dataclass
from capa.features.common import Feature
from capa.features.address import NO_ADDRESS, Address
from capa.features.extractors.base_extractor import BBHandle, InsnHandle, FunctionHandle, FeatureExtractor
@dataclass
class InstructionFeatures:
features: List[Tuple[Address, Feature]]
@dataclass
class BasicBlockFeatures:
features: List[Tuple[Address, Feature]]
instructions: Dict[Address, InstructionFeatures]
@dataclass
class FunctionFeatures:
features: List[Tuple[Address, Feature]]
basic_blocks: Dict[Address, BasicBlockFeatures]
@dataclass
class NullFeatureExtractor(FeatureExtractor):
"""
An extractor that extracts some user-provided features.
This is useful for testing, as we can provide expected values and see if matching works.
"""
base_address: Address
global_features: List[Feature]
file_features: List[Tuple[Address, Feature]]
functions: Dict[Address, FunctionFeatures]
def get_base_address(self):
return self.base_address
def extract_global_features(self):
for feature in self.global_features:
yield feature, NO_ADDRESS
def extract_file_features(self):
for address, feature in self.file_features:
yield feature, address
def get_functions(self):
for address in sorted(self.functions.keys()):
yield FunctionHandle(address, None)
def extract_function_features(self, f):
for address, feature in self.functions[f.address].features:
yield feature, address
def get_basic_blocks(self, f):
for address in sorted(self.functions[f.address].basic_blocks.keys()):
yield BBHandle(address, None)
def extract_basic_block_features(self, f, bb):
for address, feature in self.functions[f.address].basic_blocks[bb.address].features:
yield feature, address
def get_instructions(self, f, bb):
for address in sorted(self.functions[f.address].basic_blocks[bb.address].instructions.keys()):
yield InsnHandle(address, None)
def extract_insn_features(self, f, bb, insn):
for address, feature in self.functions[f.address].basic_blocks[bb.address].instructions[insn.address].features:
yield feature, address

View File

@@ -1,229 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import logging
from pathlib import Path
import pefile
import capa.features.common
import capa.features.extractors
import capa.features.extractors.common
import capa.features.extractors.helpers
import capa.features.extractors.strings
from capa.features.file import Export, Import, Section
from capa.features.common import OS, ARCH_I386, FORMAT_PE, ARCH_AMD64, OS_WINDOWS, Arch, Format, Characteristic
from capa.features.address import NO_ADDRESS, FileOffsetAddress, AbsoluteVirtualAddress
from capa.features.extractors.base_extractor import FeatureExtractor
logger = logging.getLogger(__name__)
def extract_file_embedded_pe(buf, **kwargs):
for offset, _ in capa.features.extractors.helpers.carve_pe(buf, 1):
yield Characteristic("embedded pe"), FileOffsetAddress(offset)
def extract_file_export_names(pe, **kwargs):
base_address = pe.OPTIONAL_HEADER.ImageBase
if hasattr(pe, "DIRECTORY_ENTRY_EXPORT"):
for export in pe.DIRECTORY_ENTRY_EXPORT.symbols:
if not export.name:
continue
try:
name = export.name.partition(b"\x00")[0].decode("ascii")
except UnicodeDecodeError:
continue
if export.forwarder is None:
va = base_address + export.address
yield Export(name), AbsoluteVirtualAddress(va)
else:
try:
forwarded_name = export.forwarder.partition(b"\x00")[0].decode("ascii")
except UnicodeDecodeError:
continue
forwarded_name = capa.features.extractors.helpers.reformat_forwarded_export_name(forwarded_name)
va = base_address + export.address
yield Export(forwarded_name), AbsoluteVirtualAddress(va)
yield Characteristic("forwarded export"), AbsoluteVirtualAddress(va)
def extract_file_import_names(pe, **kwargs):
"""
extract imported function names
1. imports by ordinal:
- modulename.#ordinal
2. imports by name, results in two features to support importname-only matching:
- modulename.importname
- importname
"""
if hasattr(pe, "DIRECTORY_ENTRY_IMPORT"):
for dll in pe.DIRECTORY_ENTRY_IMPORT:
try:
modname = dll.dll.partition(b"\x00")[0].decode("ascii")
except UnicodeDecodeError:
continue
# strip extension
modname = modname.rpartition(".")[0].lower()
for imp in dll.imports:
if imp.import_by_ordinal:
impname = f"#{imp.ordinal}"
else:
try:
impname = imp.name.partition(b"\x00")[0].decode("ascii")
except UnicodeDecodeError:
continue
for name in capa.features.extractors.helpers.generate_symbols(modname, impname):
yield Import(name), AbsoluteVirtualAddress(imp.address)
def extract_file_section_names(pe, **kwargs):
base_address = pe.OPTIONAL_HEADER.ImageBase
for section in pe.sections:
try:
name = section.Name.partition(b"\x00")[0].decode("ascii")
except UnicodeDecodeError:
continue
yield Section(name), AbsoluteVirtualAddress(base_address + section.VirtualAddress)
def extract_file_strings(buf, **kwargs):
yield from capa.features.extractors.common.extract_file_strings(buf)
def extract_file_function_names(**kwargs):
"""
extract the names of statically-linked library functions.
"""
if False:
# using a `yield` here to force this to be a generator, not function.
yield NotImplementedError("pefile doesn't have library matching")
return
def extract_file_os(**kwargs):
# assuming PE -> Windows
# though i suppose they're also used by UEFI
yield OS(OS_WINDOWS), NO_ADDRESS
def extract_file_format(**kwargs):
yield Format(FORMAT_PE), NO_ADDRESS
def extract_file_arch(pe, **kwargs):
if pe.FILE_HEADER.Machine == pefile.MACHINE_TYPE["IMAGE_FILE_MACHINE_I386"]:
yield Arch(ARCH_I386), NO_ADDRESS
elif pe.FILE_HEADER.Machine == pefile.MACHINE_TYPE["IMAGE_FILE_MACHINE_AMD64"]:
yield Arch(ARCH_AMD64), NO_ADDRESS
else:
logger.warning("unsupported architecture: %s", pefile.MACHINE_TYPE[pe.FILE_HEADER.Machine])
def extract_file_features(pe, buf):
"""
extract file features from given workspace
args:
pe (pefile.PE): the parsed PE
buf: the raw sample bytes
yields:
Tuple[Feature, VA]: a feature and its location.
"""
for file_handler in FILE_HANDLERS:
# file_handler: type: (pe, bytes) -> Iterable[Tuple[Feature, Address]]
for feature, va in file_handler(pe=pe, buf=buf): # type: ignore
yield feature, va
FILE_HANDLERS = (
extract_file_embedded_pe,
extract_file_export_names,
extract_file_import_names,
extract_file_section_names,
extract_file_strings,
extract_file_function_names,
extract_file_format,
)
def extract_global_features(pe, buf):
"""
extract global features from given workspace
args:
pe (pefile.PE): the parsed PE
buf: the raw sample bytes
yields:
Tuple[Feature, VA]: a feature and its location.
"""
for handler in GLOBAL_HANDLERS:
# file_handler: type: (pe, bytes) -> Iterable[Tuple[Feature, Address]]
for feature, va in handler(pe=pe, buf=buf): # type: ignore
yield feature, va
GLOBAL_HANDLERS = (
extract_file_os,
extract_file_arch,
)
class PefileFeatureExtractor(FeatureExtractor):
def __init__(self, path: Path):
super().__init__()
self.path: Path = path
self.pe = pefile.PE(str(path))
def get_base_address(self):
return AbsoluteVirtualAddress(self.pe.OPTIONAL_HEADER.ImageBase)
def extract_global_features(self):
buf = Path(self.path).read_bytes()
yield from extract_global_features(self.pe, buf)
def extract_file_features(self):
buf = Path(self.path).read_bytes()
yield from extract_file_features(self.pe, buf)
def get_functions(self):
raise NotImplementedError("PefileFeatureExtract can only be used to extract file features")
def extract_function_features(self, f):
raise NotImplementedError("PefileFeatureExtract can only be used to extract file features")
def get_basic_blocks(self, f):
raise NotImplementedError("PefileFeatureExtract can only be used to extract file features")
def extract_basic_block_features(self, f, bb):
raise NotImplementedError("PefileFeatureExtract can only be used to extract file features")
def get_instructions(self, f, bb):
raise NotImplementedError("PefileFeatureExtract can only be used to extract file features")
def extract_insn_features(self, f, bb, insn):
raise NotImplementedError("PefileFeatureExtract can only be used to extract file features")
def is_library_function(self, va):
raise NotImplementedError("PefileFeatureExtract can only be used to extract file features")
def get_function_name(self, va):
raise NotImplementedError("PefileFeatureExtract can only be used to extract file features")

View File

@@ -0,0 +1,52 @@
import sys
import types
from smda.common.SmdaReport import SmdaReport
from smda.common.SmdaInstruction import SmdaInstruction
import capa.features.extractors.smda.file
import capa.features.extractors.smda.insn
import capa.features.extractors.smda.function
import capa.features.extractors.smda.basicblock
from capa.main import UnsupportedRuntimeError
from capa.features.extractors import FeatureExtractor
class SmdaFeatureExtractor(FeatureExtractor):
def __init__(self, smda_report: SmdaReport, path):
super(SmdaFeatureExtractor, self).__init__()
if sys.version_info < (3, 0):
raise UnsupportedRuntimeError("SMDA should only be used with Python 3.")
self.smda_report = smda_report
self.path = path
def get_base_address(self):
return self.smda_report.base_addr
def extract_file_features(self):
for feature, va in capa.features.extractors.smda.file.extract_features(self.smda_report, self.path):
yield feature, va
def get_functions(self):
for function in self.smda_report.getFunctions():
yield function
def extract_function_features(self, f):
for feature, va in capa.features.extractors.smda.function.extract_features(f):
yield feature, va
def get_basic_blocks(self, f):
for bb in f.getBlocks():
yield bb
def extract_basic_block_features(self, f, bb):
for feature, va in capa.features.extractors.smda.basicblock.extract_features(f, bb):
yield feature, va
def get_instructions(self, f, bb):
for smda_ins in bb.getInstructions():
yield smda_ins
def extract_insn_features(self, f, bb, insn):
for feature, va in capa.features.extractors.smda.insn.extract_features(f, bb, insn):
yield feature, va

View File

@@ -0,0 +1,131 @@
import sys
import string
import struct
from capa.features import Characteristic
from capa.features.basicblock import BasicBlock
from capa.features.extractors.helpers import MIN_STACKSTRING_LEN
def _bb_has_tight_loop(f, bb):
"""
parse tight loops, true if last instruction in basic block branches to bb start
"""
return bb.offset in f.blockrefs[bb.offset] if bb.offset in f.blockrefs else False
def extract_bb_tight_loop(f, bb):
""" check basic block for tight loop indicators """
if _bb_has_tight_loop(f, bb):
yield Characteristic("tight loop"), bb.offset
def _bb_has_stackstring(f, bb):
"""
extract potential stackstring creation, using the following heuristics:
- basic block contains enough moves of constant bytes to the stack
"""
count = 0
for instr in bb.getInstructions():
if is_mov_imm_to_stack(instr):
count += get_printable_len(instr.getDetailed())
if count > MIN_STACKSTRING_LEN:
return True
return False
def get_operands(smda_ins):
return [o.strip() for o in smda_ins.operands.split(",")]
def extract_stackstring(f, bb):
""" check basic block for stackstring indicators """
if _bb_has_stackstring(f, bb):
yield Characteristic("stack string"), bb.offset
def is_mov_imm_to_stack(smda_ins):
"""
Return if instruction moves immediate onto stack
"""
if not smda_ins.mnemonic.startswith("mov"):
return False
try:
dst, src = get_operands(smda_ins)
except ValueError:
# not two operands
return False
try:
int(src, 16)
except ValueError:
return False
if not any(regname in dst for regname in ["ebp", "rbp", "esp", "rsp"]):
return False
return True
def is_printable_ascii(chars):
return all(c < 127 and chr(c) in string.printable for c in chars)
def is_printable_utf16le(chars):
if all(c == 0x00 for c in chars[1::2]):
return is_printable_ascii(chars[::2])
def get_printable_len(instr):
"""
Return string length if all operand bytes are ascii or utf16-le printable
Works on a capstone instruction
"""
# should have exactly two operands for mov immediate
if len(instr.operands) != 2:
return 0
op_value = instr.operands[1].value.imm
if instr.imm_size == 1:
chars = struct.pack("<B", op_value & 0xFF)
elif instr.imm_size == 2:
chars = struct.pack("<H", op_value & 0xFFFF)
elif instr.imm_size == 4:
chars = struct.pack("<I", op_value & 0xFFFFFFFF)
elif instr.imm_size == 8:
chars = struct.pack("<Q", op_value & 0xFFFFFFFFFFFFFFFF)
else:
raise ValueError("Unhandled operand data type 0x%x." % instr.imm_size)
if is_printable_ascii(chars):
return instr.imm_size
if is_printable_utf16le(chars):
return instr.imm_size // 2
return 0
def extract_features(f, bb):
"""
extract features from the given basic block.
args:
f (smda.common.SmdaFunction): the function from which to extract features
bb (smda.common.SmdaBasicBlock): the basic block to process.
yields:
Feature, set[VA]: the features and their location found in this basic block.
"""
yield BasicBlock(), bb.offset
for bb_handler in BASIC_BLOCK_HANDLERS:
for feature, va in bb_handler(f, bb):
yield feature, va
BASIC_BLOCK_HANDLERS = (
extract_bb_tight_loop,
extract_stackstring,
)

View File

@@ -0,0 +1,139 @@
import struct
# if we have SMDA we definitely have lief
import lief
import capa.features.extractors.helpers
import capa.features.extractors.strings
from capa.features import String, Characteristic
from capa.features.file import Export, Import, Section
def carve(pbytes, offset=0):
"""
Return a list of (offset, size, xor) tuples of embedded PEs
Based on the version from vivisect:
https://github.com/vivisect/vivisect/blob/7be4037b1cecc4551b397f840405a1fc606f9b53/PE/carve.py#L19
And its IDA adaptation:
capa/features/extractors/ida/file.py
"""
mz_xor = [
(
capa.features.extractors.helpers.xor_static(b"MZ", i),
capa.features.extractors.helpers.xor_static(b"PE", i),
i,
)
for i in range(256)
]
pblen = len(pbytes)
todo = [(pbytes.find(mzx, offset), mzx, pex, i) for mzx, pex, i in mz_xor]
todo = [(off, mzx, pex, i) for (off, mzx, pex, i) in todo if off != -1]
while len(todo):
off, mzx, pex, i = todo.pop()
# The MZ header has one field we will check
# e_lfanew is at 0x3c
e_lfanew = off + 0x3C
if pblen < (e_lfanew + 4):
continue
newoff = struct.unpack("<I", capa.features.extractors.helpers.xor_static(pbytes[e_lfanew : e_lfanew + 4], i))[0]
nextres = pbytes.find(mzx, off + 1)
if nextres != -1:
todo.append((nextres, mzx, pex, i))
peoff = off + newoff
if pblen < (peoff + 2):
continue
if pbytes[peoff : peoff + 2] == pex:
yield (off, i)
def extract_file_embedded_pe(smda_report, file_path):
with open(file_path, "rb") as f:
fbytes = f.read()
for offset, i in carve(fbytes, 1):
yield Characteristic("embedded pe"), offset
def extract_file_export_names(smda_report, file_path):
lief_binary = lief.parse(file_path)
if lief_binary is not None:
for function in lief_binary.exported_functions:
yield Export(function.name), function.address
def extract_file_import_names(smda_report, file_path):
# extract import table info via LIEF
lief_binary = lief.parse(file_path)
if not isinstance(lief_binary, lief.PE.Binary):
return
for imported_library in lief_binary.imports:
library_name = imported_library.name.lower()
library_name = library_name[:-4] if library_name.endswith(".dll") else library_name
for func in imported_library.entries:
if func.name:
va = func.iat_address + smda_report.base_addr
for name in capa.features.extractors.helpers.generate_symbols(library_name, func.name):
yield Import(name), va
elif func.is_ordinal:
for name in capa.features.extractors.helpers.generate_symbols(library_name, "#%s" % func.ordinal):
yield Import(name), va
def extract_file_section_names(smda_report, file_path):
lief_binary = lief.parse(file_path)
if not isinstance(lief_binary, lief.PE.Binary):
return
if lief_binary and lief_binary.sections:
base_address = lief_binary.optional_header.imagebase
for section in lief_binary.sections:
yield Section(section.name), base_address + section.virtual_address
def extract_file_strings(smda_report, file_path):
"""
extract ASCII and UTF-16 LE strings from file
"""
with open(file_path, "rb") as f:
b = f.read()
for s in capa.features.extractors.strings.extract_ascii_strings(b):
yield String(s.s), s.offset
for s in capa.features.extractors.strings.extract_unicode_strings(b):
yield String(s.s), s.offset
def extract_features(smda_report, file_path):
"""
extract file features from given workspace
args:
smda_report (smda.common.SmdaReport): a SmdaReport
file_path: path to the input file
yields:
Tuple[Feature, VA]: a feature and its location.
"""
for file_handler in FILE_HANDLERS:
result = file_handler(smda_report, file_path)
for feature, va in file_handler(smda_report, file_path):
yield feature, va
FILE_HANDLERS = (
extract_file_embedded_pe,
extract_file_export_names,
extract_file_import_names,
extract_file_section_names,
extract_file_strings,
)

View File

@@ -0,0 +1,38 @@
from capa.features import Characteristic
from capa.features.extractors import loops
def extract_function_calls_to(f):
for inref in f.inrefs:
yield Characteristic("calls to"), inref
def extract_function_loop(f):
"""
parse if a function has a loop
"""
edges = []
for bb_from, bb_tos in f.blockrefs.items():
for bb_to in bb_tos:
edges.append((bb_from, bb_to))
if edges and loops.has_loop(edges):
yield Characteristic("loop"), f.offset
def extract_features(f):
"""
extract features from the given function.
args:
f (smda.common.SmdaFunction): the function from which to extract features
yields:
Feature, set[VA]: the features and their location found in this function.
"""
for func_handler in FUNCTION_HANDLERS:
for feature, va in func_handler(f):
yield feature, va
FUNCTION_HANDLERS = (extract_function_calls_to, extract_function_loop)

View File

@@ -0,0 +1,393 @@
import re
import string
import struct
from smda.common.SmdaReport import SmdaReport
import capa.features.extractors.helpers
from capa.features import (
ARCH_X32,
ARCH_X64,
MAX_BYTES_FEATURE_SIZE,
THUNK_CHAIN_DEPTH_DELTA,
Bytes,
String,
Characteristic,
)
from capa.features.insn import API, Number, Offset, Mnemonic
# security cookie checks may perform non-zeroing XORs, these are expected within a certain
# byte range within the first and returning basic blocks, this helps to reduce FP features
SECURITY_COOKIE_BYTES_DELTA = 0x40
PATTERN_HEXNUM = re.compile(r"[+\-] (?P<num>0x[a-fA-F0-9]+)")
PATTERN_SINGLENUM = re.compile(r"[+\-] (?P<num>[0-9])")
def get_arch(smda_report):
if smda_report.architecture == "intel":
if smda_report.bitness == 32:
return ARCH_X32
elif smda_report.bitness == 64:
return ARCH_X64
else:
raise NotImplementedError
def extract_insn_api_features(f, bb, insn):
"""parse API features from the given instruction."""
if insn.offset in f.apirefs:
api_entry = f.apirefs[insn.offset]
# reformat
dll_name, api_name = api_entry.split("!")
dll_name = dll_name.split(".")[0]
dll_name = dll_name.lower()
for name in capa.features.extractors.helpers.generate_symbols(dll_name, api_name):
yield API(name), insn.offset
elif insn.offset in f.outrefs:
current_function = f
current_instruction = insn
for index in range(THUNK_CHAIN_DEPTH_DELTA):
if current_function and len(current_function.outrefs[current_instruction.offset]) == 1:
target = current_function.outrefs[current_instruction.offset][0]
referenced_function = current_function.smda_report.getFunction(target)
if referenced_function:
# TODO SMDA: implement this function for both jmp and call, checking if function has 1 instruction which refs an API
if referenced_function.isApiThunk():
api_entry = (
referenced_function.apirefs[target] if target in referenced_function.apirefs else None
)
if api_entry:
# reformat
dll_name, api_name = api_entry.split("!")
dll_name = dll_name.split(".")[0]
dll_name = dll_name.lower()
for name in capa.features.extractors.helpers.generate_symbols(dll_name, api_name):
yield API(name), insn.offset
elif referenced_function.num_instructions == 1 and referenced_function.num_outrefs == 1:
current_function = referenced_function
current_instruction = [i for i in referenced_function.getInstructions()][0]
else:
return
def extract_insn_number_features(f, bb, insn):
"""parse number features from the given instruction."""
# example:
#
# push 3136B0h ; dwControlCode
operands = [o.strip() for o in insn.operands.split(",")]
if insn.mnemonic == "add" and operands[0] in ["esp", "rsp"]:
# skip things like:
#
# .text:00401140 call sub_407E2B
# .text:00401145 add esp, 0Ch
return
for operand in operands:
try:
yield Number(int(operand, 16)), insn.offset
yield Number(int(operand, 16), arch=get_arch(f.smda_report)), insn.offset
except:
continue
def read_bytes(smda_report, va, num_bytes=None):
"""
read up to MAX_BYTES_FEATURE_SIZE from the given address.
"""
rva = va - smda_report.base_addr
if smda_report.buffer is None:
return
buffer_end = len(smda_report.buffer)
max_bytes = num_bytes if num_bytes is not None else MAX_BYTES_FEATURE_SIZE
if rva + max_bytes > buffer_end:
return smda_report.buffer[rva:]
else:
return smda_report.buffer[rva : rva + max_bytes]
def derefs(smda_report, p):
"""
recursively follow the given pointer, yielding the valid memory addresses along the way.
useful when you may have a pointer to string, or pointer to pointer to string, etc.
this is a "do what i mean" type of helper function.
based on the implementation in viv/insn.py
"""
depth = 0
while True:
if not smda_report.isAddrWithinMemoryImage(p):
return
yield p
bytes_ = read_bytes(smda_report, p, num_bytes=4)
val = struct.unpack("I", bytes_)[0]
# sanity: pointer points to self
if val == p:
return
# sanity: avoid chains of pointers that are unreasonably deep
depth += 1
if depth > 10:
return
p = val
def extract_insn_bytes_features(f, bb, insn):
"""
parse byte sequence features from the given instruction.
example:
# push offset iid_004118d4_IShellLinkA ; riid
"""
for data_ref in insn.getDataRefs():
for v in derefs(f.smda_report, data_ref):
bytes_read = read_bytes(f.smda_report, v)
if bytes_read is None:
continue
if capa.features.extractors.helpers.all_zeros(bytes_read):
continue
yield Bytes(bytes_read), insn.offset
def detect_ascii_len(smda_report, offset):
if smda_report.buffer is None:
return 0
ascii_len = 0
rva = offset - smda_report.base_addr
char = smda_report.buffer[rva]
while char < 127 and chr(char) in string.printable:
ascii_len += 1
rva += 1
char = smda_report.buffer[rva]
if char == 0:
return ascii_len
return 0
def detect_unicode_len(smda_report, offset):
if smda_report.buffer is None:
return 0
unicode_len = 0
rva = offset - smda_report.base_addr
char = smda_report.buffer[rva]
second_char = smda_report.buffer[rva + 1]
while char < 127 and chr(char) in string.printable and second_char == 0:
unicode_len += 2
rva += 2
char = smda_report.buffer[rva]
second_char = smda_report.buffer[rva + 1]
if char == 0 and second_char == 0:
return unicode_len
return 0
def read_string(smda_report, offset):
alen = detect_ascii_len(smda_report, offset)
if alen > 1:
return read_bytes(smda_report, offset, alen).decode("utf-8")
ulen = detect_unicode_len(smda_report, offset)
if ulen > 2:
return read_bytes(smda_report, offset, ulen).decode("utf-16")
def extract_insn_string_features(f, bb, insn):
"""parse string features from the given instruction."""
# example:
#
# push offset aAcr ; "ACR > "
for data_ref in insn.getDataRefs():
for v in derefs(f.smda_report, data_ref):
string_read = read_string(f.smda_report, v)
if string_read:
yield String(string_read.rstrip("\x00")), insn.offset
def extract_insn_offset_features(f, bb, insn):
"""parse structure offset features from the given instruction."""
# examples:
#
# mov eax, [esi + 4]
# mov eax, [esi + ecx + 16384]
operands = [o.strip() for o in insn.operands.split(",")]
for operand in operands:
if not "ptr" in operand:
continue
if "esp" in operand or "ebp" in operand or "rbp" in operand:
continue
number = 0
number_hex = re.search(PATTERN_HEXNUM, operand)
number_int = re.search(PATTERN_SINGLENUM, operand)
if number_hex:
number = int(number_hex.group("num"), 16)
number = -1 * number if number_hex.group().startswith("-") else number
elif number_int:
number = int(number_int.group("num"))
number = -1 * number if number_int.group().startswith("-") else number
yield Offset(number), insn.offset
yield Offset(number, arch=get_arch(f.smda_report)), insn.offset
def is_security_cookie(f, bb, insn):
"""
check if an instruction is related to security cookie checks
"""
# security cookie check should use SP or BP
operands = [o.strip() for o in insn.operands.split(",")]
if operands[1] not in ["esp", "ebp", "rsp", "rbp"]:
return False
for index, block in enumerate(f.getBlocks()):
# expect security cookie init in first basic block within first bytes (instructions)
block_instructions = [i for i in block.getInstructions()]
if index == 0 and insn.offset < (block_instructions[0].offset + SECURITY_COOKIE_BYTES_DELTA):
return True
# ... or within last bytes (instructions) before a return
if block_instructions[-1].mnemonic.startswith("ret") and insn.offset > (
block_instructions[-1].offset - SECURITY_COOKIE_BYTES_DELTA
):
return True
return False
def extract_insn_nzxor_characteristic_features(f, bb, insn):
"""
parse non-zeroing XOR instruction from the given instruction.
ignore expected non-zeroing XORs, e.g. security cookies.
"""
if insn.mnemonic not in ("xor", "xorpd", "xorps", "pxor"):
return
operands = [o.strip() for o in insn.operands.split(",")]
if operands[0] == operands[1]:
return
if is_security_cookie(f, bb, insn):
return
yield Characteristic("nzxor"), insn.offset
def extract_insn_mnemonic_features(f, bb, insn):
"""parse mnemonic features from the given instruction."""
yield Mnemonic(insn.mnemonic), insn.offset
def extract_insn_peb_access_characteristic_features(f, bb, insn):
"""
parse peb access from the given function. fs:[0x30] on x86, gs:[0x60] on x64
"""
if insn.mnemonic not in ["push", "mov"]:
return
operands = [o.strip() for o in insn.operands.split(",")]
for operand in operands:
if "fs:" in operand and "0x30" in operand:
yield Characteristic("peb access"), insn.offset
elif "gs:" in operand and "0x60" in operand:
yield Characteristic("peb access"), insn.offset
def extract_insn_segment_access_features(f, bb, insn):
""" parse the instruction for access to fs or gs """
operands = [o.strip() for o in insn.operands.split(",")]
for operand in operands:
if "fs:" in operand:
yield Characteristic("fs access"), insn.offset
elif "gs:" in operand:
yield Characteristic("gs access"), insn.offset
def extract_insn_cross_section_cflow(f, bb, insn):
"""
inspect the instruction for a CALL or JMP that crosses section boundaries.
"""
if insn.mnemonic in ["call", "jmp"]:
if insn.offset in f.apirefs:
return
smda_report = insn.smda_function.smda_report
if insn.offset in f.outrefs:
for target in f.outrefs[insn.offset]:
if smda_report.getSection(insn.offset) != smda_report.getSection(target):
yield Characteristic("cross section flow"), insn.offset
elif insn.operands.startswith("0x"):
target = int(insn.operands, 16)
if smda_report.getSection(insn.offset) != smda_report.getSection(target):
yield Characteristic("cross section flow"), insn.offset
# this is a feature that's most relevant at the function scope,
# however, its most efficient to extract at the instruction scope.
def extract_function_calls_from(f, bb, insn):
if insn.mnemonic != "call":
return
if insn.offset in f.outrefs:
for outref in f.outrefs[insn.offset]:
yield Characteristic("calls from"), outref
if outref == f.offset:
# if we found a jump target and it's the function address
# mark as recursive
yield Characteristic("recursive call"), outref
if insn.offset in f.apirefs:
yield Characteristic("calls from"), insn.offset
# this is a feature that's most relevant at the function or basic block scope,
# however, its most efficient to extract at the instruction scope.
def extract_function_indirect_call_characteristic_features(f, bb, insn):
"""
extract indirect function call characteristic (e.g., call eax or call dword ptr [edx+4])
does not include calls like => call ds:dword_ABD4974
"""
if insn.mnemonic != "call":
return
if insn.operands.startswith("0x"):
return False
if "qword ptr" in insn.operands and "rip" in insn.operands:
return False
if insn.operands.startswith("dword ptr [0x"):
return False
# call edx
# call dword ptr [eax+50h]
# call qword ptr [rsp+78h]
yield Characteristic("indirect call"), insn.offset
def extract_features(f, bb, insn):
"""
extract features from the given insn.
args:
f (smda.common.SmdaFunction): the function to process.
bb (smda.common.SmdaBasicBlock): the basic block to process.
insn (smda.common.SmdaInstruction): the instruction to process.
yields:
Feature, set[VA]: the features and their location found in this insn.
"""
for insn_handler in INSTRUCTION_HANDLERS:
for feature, va in insn_handler(f, bb, insn):
yield feature, va
INSTRUCTION_HANDLERS = (
extract_insn_api_features,
extract_insn_number_features,
extract_insn_string_features,
extract_insn_bytes_features,
extract_insn_offset_features,
extract_insn_nzxor_characteristic_features,
extract_insn_mnemonic_features,
extract_insn_peb_access_characteristic_features,
extract_insn_cross_section_cflow,
extract_insn_segment_access_features,
extract_function_calls_from,
extract_function_indirect_call_characteristic_features,
)

View File

@@ -1,6 +1,6 @@
# strings code from FLOSS, https://github.com/mandiant/flare-floss
# strings code from FLOSS, https://github.com/fireeye/flare-floss
#
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
@@ -9,7 +9,6 @@
# See the License for the specific language governing permissions and limitations under the License.
import re
import contextlib
from collections import namedtuple
ASCII_BYTE = r" !\"#\$%&\'\(\)\*\+,-\./0123456789:;<=>\?@ABCDEFGHIJKLMNOPQRSTUVWXYZ\[\]\^_`abcdefghijklmnopqrstuvwxyz\{\|\}\\\~\t".encode(
@@ -82,5 +81,24 @@ def extract_unicode_strings(buf, n=4):
reg = b"((?:[%s]\x00){%d,})" % (ASCII_BYTE, n)
r = re.compile(reg)
for match in r.finditer(buf):
with contextlib.suppress(UnicodeDecodeError):
try:
yield String(match.group().decode("utf-16"), match.start())
except UnicodeDecodeError:
pass
def main():
import sys
with open(sys.argv[1], "rb") as f:
b = f.read()
for s in extract_ascii_strings(b):
print("0x{:x}: {:s}".format(s.offset, s.s))
for s in extract_unicode_strings(b):
print("0x{:x}: {:s}".format(s.offset, s.s))
if __name__ == "__main__":
main()

View File

@@ -0,0 +1,81 @@
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import types
import viv_utils
import capa.features.extractors
import capa.features.extractors.viv.file
import capa.features.extractors.viv.insn
import capa.features.extractors.viv.function
import capa.features.extractors.viv.basicblock
from capa.features.extractors import FeatureExtractor
__all__ = ["file", "function", "basicblock", "insn"]
def get_va(self):
try:
# vivisect type
return self.va
except AttributeError:
pass
raise TypeError()
def add_va_int_cast(o):
"""
dynamically add a cast-to-int (`__int__`) method to the given object
that returns the value of the `.va` property.
this bit of skullduggery lets use cast viv-utils objects as ints.
the correct way of doing this is to update viv-utils (or subclass the objects here).
"""
setattr(o, "__int__", types.MethodType(get_va, o))
return o
class VivisectFeatureExtractor(FeatureExtractor):
def __init__(self, vw, path):
super(VivisectFeatureExtractor, self).__init__()
self.vw = vw
self.path = path
def get_base_address(self):
# assume there is only one file loaded into the vw
return list(self.vw.filemeta.values())[0]["imagebase"]
def extract_file_features(self):
for feature, va in capa.features.extractors.viv.file.extract_features(self.vw, self.path):
yield feature, va
def get_functions(self):
for va in sorted(self.vw.getFunctions()):
yield add_va_int_cast(viv_utils.Function(self.vw, va))
def extract_function_features(self, f):
for feature, va in capa.features.extractors.viv.function.extract_features(f):
yield feature, va
def get_basic_blocks(self, f):
for bb in f.basic_blocks:
yield add_va_int_cast(bb)
def extract_basic_block_features(self, f, bb):
for feature, va in capa.features.extractors.viv.basicblock.extract_features(f, bb):
yield feature, va
def get_instructions(self, f, bb):
for insn in bb.instructions:
yield add_va_int_cast(insn)
def extract_insn_features(self, f, bb, insn):
for feature, va in capa.features.extractors.viv.insn.extract_features(f, bb, insn):
yield feature, va

View File

@@ -1,4 +1,4 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
@@ -8,30 +8,27 @@
import string
import struct
from typing import Tuple, Iterator
import envi
import envi.archs.i386.disasm
import vivisect.const
from capa.features.common import Feature, Characteristic
from capa.features.address import Address, AbsoluteVirtualAddress
from capa.features import Characteristic
from capa.features.basicblock import BasicBlock
from capa.features.extractors.helpers import MIN_STACKSTRING_LEN
from capa.features.extractors.base_extractor import BBHandle, FunctionHandle
def interface_extract_basic_block_XXX(f: FunctionHandle, bb: BBHandle) -> Iterator[Tuple[Feature, Address]]:
def interface_extract_basic_block_XXX(f, bb):
"""
parse features from the given basic block.
args:
f: the function to process.
bb: the basic block to process.
f (viv_utils.Function): the function to process.
bb (viv_utils.BasicBlock): the basic block to process.
yields:
(Feature, Address): the feature and the address at which its found.
(Feature, int): the feature and the address at which its found.
"""
raise NotImplementedError
yield NotImplementedError("feature"), NotImplementedError("virtual address")
def _bb_has_tight_loop(f, bb):
@@ -40,17 +37,17 @@ def _bb_has_tight_loop(f, bb):
"""
if len(bb.instructions) > 0:
for bva, bflags in bb.instructions[-1].getBranches():
if bflags & envi.BR_COND:
if bflags & vivisect.envi.BR_COND:
if bva == bb.va:
return True
return False
def extract_bb_tight_loop(f: FunctionHandle, bb: BBHandle) -> Iterator[Tuple[Feature, Address]]:
"""check basic block for tight loop indicators"""
if _bb_has_tight_loop(f, bb.inner):
yield Characteristic("tight loop"), bb.address
def extract_bb_tight_loop(f, bb):
""" check basic block for tight loop indicators """
if _bb_has_tight_loop(f, bb):
yield Characteristic("tight loop"), bb.va
def _bb_has_stackstring(f, bb):
@@ -70,13 +67,13 @@ def _bb_has_stackstring(f, bb):
return False
def extract_stackstring(f: FunctionHandle, bb: BBHandle) -> Iterator[Tuple[Feature, Address]]:
"""check basic block for stackstring indicators"""
if _bb_has_stackstring(f, bb.inner):
yield Characteristic("stack string"), bb.address
def extract_stackstring(f, bb):
""" check basic block for stackstring indicators """
if _bb_has_stackstring(f, bb):
yield Characteristic("stack string"), bb.va
def is_mov_imm_to_stack(instr: envi.archs.i386.disasm.i386Opcode) -> bool:
def is_mov_imm_to_stack(instr):
"""
Return if instruction moves immediate onto stack
"""
@@ -92,6 +89,7 @@ def is_mov_imm_to_stack(instr: envi.archs.i386.disasm.i386Opcode) -> bool:
if not src.isImmed():
return False
# TODO what about 64-bit operands?
if not isinstance(dst, envi.archs.i386.disasm.i386SibOper) and not isinstance(
dst, envi.archs.i386.disasm.i386RegMemOper
):
@@ -107,7 +105,7 @@ def is_mov_imm_to_stack(instr: envi.archs.i386.disasm.i386Opcode) -> bool:
return True
def get_printable_len(oper: envi.archs.i386.disasm.i386ImmOper) -> int:
def get_printable_len(oper):
"""
Return string length if all operand bytes are ascii or utf16-le printable
"""
@@ -119,18 +117,14 @@ def get_printable_len(oper: envi.archs.i386.disasm.i386ImmOper) -> int:
chars = struct.pack("<I", oper.imm)
elif oper.tsize == 8:
chars = struct.pack("<Q", oper.imm)
else:
raise ValueError(f"unexpected oper.tsize: {oper.tsize}")
if is_printable_ascii(chars):
return oper.tsize
elif is_printable_utf16le(chars):
if is_printable_utf16le(chars):
return oper.tsize / 2
else:
return 0
return 0
def is_printable_ascii(chars: bytes) -> bool:
def is_printable_ascii(chars):
try:
chars_str = chars.decode("ascii")
except UnicodeDecodeError:
@@ -139,13 +133,12 @@ def is_printable_ascii(chars: bytes) -> bool:
return all(c in string.printable for c in chars_str)
def is_printable_utf16le(chars: bytes) -> bool:
def is_printable_utf16le(chars):
if all(c == b"\x00" for c in chars[1::2]):
return is_printable_ascii(chars[::2])
return False
def extract_features(f: FunctionHandle, bb: BBHandle) -> Iterator[Tuple[Feature, Address]]:
def extract_features(f, bb):
"""
extract features from the given basic block.
@@ -154,12 +147,12 @@ def extract_features(f: FunctionHandle, bb: BBHandle) -> Iterator[Tuple[Feature,
bb (viv_utils.BasicBlock): the basic block to process.
yields:
Tuple[Feature, int]: the features and their location found in this basic block.
Feature, set[VA]: the features and their location found in this basic block.
"""
yield BasicBlock(), AbsoluteVirtualAddress(bb.inner.va)
yield BasicBlock(), bb.va
for bb_handler in BASIC_BLOCK_HANDLERS:
for feature, addr in bb_handler(f, bb):
yield feature, addr
for feature, va in bb_handler(f, bb):
yield feature, va
BASIC_BLOCK_HANDLERS = (

View File

@@ -1,83 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import logging
from typing import Any, Dict, List, Tuple, Iterator
from pathlib import Path
import viv_utils
import viv_utils.flirt
import capa.features.extractors.common
import capa.features.extractors.viv.file
import capa.features.extractors.viv.insn
import capa.features.extractors.viv.global_
import capa.features.extractors.viv.function
import capa.features.extractors.viv.basicblock
from capa.features.common import Feature
from capa.features.address import Address, AbsoluteVirtualAddress
from capa.features.extractors.base_extractor import BBHandle, InsnHandle, FunctionHandle, FeatureExtractor
logger = logging.getLogger(__name__)
class VivisectFeatureExtractor(FeatureExtractor):
def __init__(self, vw, path: Path, os):
super().__init__()
self.vw = vw
self.path = path
self.buf = path.read_bytes()
# pre-compute these because we'll yield them at *every* scope.
self.global_features: List[Tuple[Feature, Address]] = []
self.global_features.extend(capa.features.extractors.viv.file.extract_file_format(self.buf))
self.global_features.extend(capa.features.extractors.common.extract_os(self.buf, os))
self.global_features.extend(capa.features.extractors.viv.global_.extract_arch(self.vw))
def get_base_address(self):
# assume there is only one file loaded into the vw
return AbsoluteVirtualAddress(list(self.vw.filemeta.values())[0]["imagebase"])
def extract_global_features(self):
yield from self.global_features
def extract_file_features(self):
yield from capa.features.extractors.viv.file.extract_features(self.vw, self.buf)
def get_functions(self) -> Iterator[FunctionHandle]:
cache: Dict[str, Any] = {}
for va in sorted(self.vw.getFunctions()):
yield FunctionHandle(
address=AbsoluteVirtualAddress(va), inner=viv_utils.Function(self.vw, va), ctx={"cache": cache}
)
def extract_function_features(self, fh: FunctionHandle) -> Iterator[Tuple[Feature, Address]]:
yield from capa.features.extractors.viv.function.extract_features(fh)
def get_basic_blocks(self, fh: FunctionHandle) -> Iterator[BBHandle]:
f: viv_utils.Function = fh.inner
for bb in f.basic_blocks:
yield BBHandle(address=AbsoluteVirtualAddress(bb.va), inner=bb)
def extract_basic_block_features(self, fh: FunctionHandle, bbh) -> Iterator[Tuple[Feature, Address]]:
yield from capa.features.extractors.viv.basicblock.extract_features(fh, bbh)
def get_instructions(self, fh: FunctionHandle, bbh: BBHandle) -> Iterator[InsnHandle]:
bb: viv_utils.BasicBlock = bbh.inner
for insn in bb.instructions:
yield InsnHandle(address=AbsoluteVirtualAddress(insn.va), inner=insn)
def extract_insn_features(
self, fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
yield from capa.features.extractors.viv.insn.extract_features(fh, bbh, ih)
def is_library_function(self, addr):
return viv_utils.flirt.is_library_function(self.vw, addr)
def get_function_name(self, addr):
return viv_utils.get_function_name(self.vw, addr)

View File

@@ -1,62 +1,33 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
from typing import Tuple, Iterator
import PE.carve as pe_carve # vivisect PE
import vivisect
import viv_utils
import viv_utils.flirt
import capa.features.insn
import capa.features.extractors.common
import capa.features.extractors.helpers
import capa.features.extractors.strings
from capa.features.file import Export, Import, Section, FunctionName
from capa.features.common import Feature, Characteristic
from capa.features.address import Address, FileOffsetAddress, AbsoluteVirtualAddress
from capa.features import String, Characteristic
from capa.features.file import Export, Import, Section
def extract_file_embedded_pe(buf, **kwargs) -> Iterator[Tuple[Feature, Address]]:
for offset, _ in pe_carve.carve(buf, 1):
yield Characteristic("embedded pe"), FileOffsetAddress(offset)
def extract_file_embedded_pe(vw, file_path):
with open(file_path, "rb") as f:
fbytes = f.read()
for offset, i in pe_carve.carve(fbytes, 1):
yield Characteristic("embedded pe"), offset
def get_first_vw_filename(vw: vivisect.VivWorkspace):
# vivisect associates metadata with each file that its loaded into the workspace.
# capa only loads a single file into each workspace.
# so to access the metadata for the file in question, we can just take the first one.
# otherwise, we'd have to pass around the module name of the file we're analyzing,
# which is a pain.
#
# so this is a simplifying assumption.
return next(iter(vw.filemeta.keys()))
def extract_file_export_names(vw, file_path):
for va, etype, name, _ in vw.getExports():
yield Export(name), va
def extract_file_export_names(vw: vivisect.VivWorkspace, **kwargs) -> Iterator[Tuple[Feature, Address]]:
for va, _, name, _ in vw.getExports():
yield Export(name), AbsoluteVirtualAddress(va)
if vw.getMeta("Format") == "pe":
pe = vw.parsedbin
baseaddr = pe.IMAGE_NT_HEADERS.OptionalHeader.ImageBase
for rva, _, forwarded_name in vw.getFileMeta(get_first_vw_filename(vw), "forwarders"):
try:
forwarded_name = forwarded_name.partition(b"\x00")[0].decode("ascii")
except UnicodeDecodeError:
continue
forwarded_name = capa.features.extractors.helpers.reformat_forwarded_export_name(forwarded_name)
va = baseaddr + rva
yield Export(forwarded_name), AbsoluteVirtualAddress(va)
yield Characteristic("forwarded export"), AbsoluteVirtualAddress(va)
def extract_file_import_names(vw, **kwargs) -> Iterator[Tuple[Feature, Address]]:
def extract_file_import_names(vw, file_path):
"""
extract imported function names
1. imports by ordinal:
@@ -67,17 +38,16 @@ def extract_file_import_names(vw, **kwargs) -> Iterator[Tuple[Feature, Address]]
"""
for va, _, _, tinfo in vw.getImports():
# vivisect source: tinfo = "%s.%s" % (libname, impname)
modname, impname = tinfo.split(".", 1)
modname, impname = tinfo.split(".")
if is_viv_ord_impname(impname):
# replace ord prefix with #
impname = "#" + impname[len("ord") :]
impname = "#%s" % impname[len("ord") :]
addr = AbsoluteVirtualAddress(va)
for name in capa.features.extractors.helpers.generate_symbols(modname, impname):
yield Import(name), addr
yield Import(name), va
def is_viv_ord_impname(impname: str) -> bool:
def is_viv_ord_impname(impname):
"""
return if import name matches vivisect's ordinal naming scheme `'ord%d' % ord`
"""
@@ -91,51 +61,40 @@ def is_viv_ord_impname(impname: str) -> bool:
return True
def extract_file_section_names(vw, **kwargs) -> Iterator[Tuple[Feature, Address]]:
def extract_file_section_names(vw, file_path):
for va, _, segname, _ in vw.getSegments():
yield Section(segname), AbsoluteVirtualAddress(va)
yield Section(segname), va
def extract_file_strings(buf, **kwargs) -> Iterator[Tuple[Feature, Address]]:
yield from capa.features.extractors.common.extract_file_strings(buf)
def extract_file_function_names(vw, **kwargs) -> Iterator[Tuple[Feature, Address]]:
def extract_file_strings(vw, file_path):
"""
extract the names of statically-linked library functions.
extract ASCII and UTF-16 LE strings from file
"""
for va in sorted(vw.getFunctions()):
addr = AbsoluteVirtualAddress(va)
if viv_utils.flirt.is_library_function(vw, va):
name = viv_utils.get_function_name(vw, va)
yield FunctionName(name), addr
if name.startswith("_"):
# some linkers may prefix linked routines with a `_` to avoid name collisions.
# extract features for both the mangled and un-mangled representations.
# e.g. `_fwrite` -> `fwrite`
# see: https://stackoverflow.com/a/2628384/87207
yield FunctionName(name[1:]), addr
with open(file_path, "rb") as f:
b = f.read()
for s in capa.features.extractors.strings.extract_ascii_strings(b):
yield String(s.s), s.offset
for s in capa.features.extractors.strings.extract_unicode_strings(b):
yield String(s.s), s.offset
def extract_file_format(buf, **kwargs) -> Iterator[Tuple[Feature, Address]]:
yield from capa.features.extractors.common.extract_format(buf)
def extract_features(vw, buf: bytes) -> Iterator[Tuple[Feature, Address]]:
def extract_features(vw, file_path):
"""
extract file features from given workspace
args:
vw (vivisect.VivWorkspace): the vivisect workspace
buf: the raw input file bytes
file_path: path to the input file
yields:
Tuple[Feature, Address]: a feature and its location.
Tuple[Feature, VA]: a feature and its location.
"""
for file_handler in FILE_HANDLERS:
for feature, addr in file_handler(vw=vw, buf=buf): # type: ignore
yield feature, addr
for feature, va in file_handler(vw, file_path):
yield feature, va
FILE_HANDLERS = (
@@ -144,6 +103,4 @@ FILE_HANDLERS = (
extract_file_import_names,
extract_file_section_names,
extract_file_strings,
extract_file_function_names,
extract_file_format,
)

View File

@@ -1,110 +1,70 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
from typing import Tuple, Iterator
import envi
import viv_utils
import vivisect.const
from capa.features.file import FunctionName
from capa.features.common import Feature, Characteristic
from capa.features.address import Address, AbsoluteVirtualAddress
from capa.features import Characteristic
from capa.features.extractors import loops
from capa.features.extractors.elf import SymTab
from capa.features.extractors.base_extractor import FunctionHandle
def interface_extract_function_XXX(fh: FunctionHandle) -> Iterator[Tuple[Feature, Address]]:
def interface_extract_function_XXX(f):
"""
parse features from the given function.
args:
f: the function to process.
f (viv_utils.Function): the function to process.
yields:
(Feature, Address): the feature and the address at which its found.
(Feature, int): the feature and the address at which its found.
"""
raise NotImplementedError
yield NotImplementedError("feature"), NotImplementedError("virtual address")
def extract_function_symtab_names(fh: FunctionHandle) -> Iterator[Tuple[Feature, Address]]:
if fh.inner.vw.metadata["Format"] == "elf":
# the file's symbol table gets added to the metadata of the vivisect workspace.
# this is in order to eliminate the computational overhead of refetching symtab each time.
if "symtab" not in fh.ctx["cache"]:
try:
fh.ctx["cache"]["symtab"] = SymTab.from_viv(fh.inner.vw.parsedbin)
except Exception:
fh.ctx["cache"]["symtab"] = None
symtab = fh.ctx["cache"]["symtab"]
if symtab:
for symbol in symtab.get_symbols():
sym_name = symtab.get_name(symbol)
sym_value = symbol.value
sym_info = symbol.info
STT_FUNC = 0x2
if sym_value == fh.address and sym_info & STT_FUNC != 0:
yield FunctionName(sym_name), fh.address
def extract_function_calls_to(fhandle: FunctionHandle) -> Iterator[Tuple[Feature, Address]]:
f: viv_utils.Function = fhandle.inner
def extract_function_calls_to(f):
for src, _, _, _ in f.vw.getXrefsTo(f.va, rtype=vivisect.const.REF_CODE):
yield Characteristic("calls to"), AbsoluteVirtualAddress(src)
yield Characteristic("calls to"), src
def extract_function_loop(fhandle: FunctionHandle) -> Iterator[Tuple[Feature, Address]]:
def extract_function_loop(f):
"""
parse if a function has a loop
"""
f: viv_utils.Function = fhandle.inner
edges = []
for bb in f.basic_blocks:
if len(bb.instructions) > 0:
for bva, bflags in bb.instructions[-1].getBranches():
if bva is None:
# vivisect may be unable to recover the call target, e.g. on dynamic calls like `call esi`
# for this bva is None, and we don't want to add it for loop detection, ref: vivisect#574
continue
# vivisect does not set branch flags for non-conditional jmp so add explicit check
if (
bflags & envi.BR_COND
or bflags & envi.BR_FALL
or bflags & envi.BR_TABLE
bflags & vivisect.envi.BR_COND
or bflags & vivisect.envi.BR_FALL
or bflags & vivisect.envi.BR_TABLE
or bb.instructions[-1].mnem == "jmp"
):
edges.append((bb.va, bva))
if edges and loops.has_loop(edges):
yield Characteristic("loop"), fhandle.address
yield Characteristic("loop"), f.va
def extract_features(fh: FunctionHandle) -> Iterator[Tuple[Feature, Address]]:
def extract_features(f):
"""
extract features from the given function.
args:
fh: the function handle from which to extract features
f (viv_utils.Function): the function from which to extract features
yields:
Tuple[Feature, int]: the features and their location found in this function.
Feature, set[VA]: the features and their location found in this function.
"""
for func_handler in FUNCTION_HANDLERS:
for feature, addr in func_handler(fh):
yield feature, addr
for feature, va in func_handler(f):
yield feature, va
FUNCTION_HANDLERS = (
extract_function_symtab_names,
extract_function_calls_to,
extract_function_loop,
)
FUNCTION_HANDLERS = (extract_function_calls_to, extract_function_loop)

View File

@@ -1,31 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import logging
from typing import Tuple, Iterator
from capa.features.common import ARCH_I386, ARCH_AMD64, Arch, Feature
from capa.features.address import NO_ADDRESS, Address
logger = logging.getLogger(__name__)
def extract_arch(vw) -> Iterator[Tuple[Feature, Address]]:
arch = vw.getMeta("Architecture")
if arch == "amd64":
yield Arch(ARCH_AMD64), NO_ADDRESS
elif arch == "i386":
yield Arch(ARCH_I386), NO_ADDRESS
else:
# we likely end up here:
# 1. handling a new architecture (e.g. aarch64)
#
# for (1), this logic will need to be updated as the format is implemented.
logger.debug("unsupported architecture: %s", vw.arch.__class__.__name__)
return

View File

@@ -1,17 +1,14 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
from typing import Optional
from vivisect import VivWorkspace
from vivisect.const import XR_TO, REF_CODE
def get_coderef_from(vw: VivWorkspace, va: int) -> Optional[int]:
def get_coderef_from(vw, va):
"""
return first code `tova` whose origin is the specified va
return None if no code reference is found

View File

@@ -1,4 +1,4 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
@@ -7,13 +7,11 @@
# See the License for the specific language governing permissions and limitations under the License.
import collections
from typing import Set, List, Deque, Tuple, Optional
import envi
import vivisect.const
import envi.archs.i386.disasm
import envi.archs.amd64.disasm
from vivisect import VivWorkspace
# pull out consts for lookup performance
i386RegOper = envi.archs.i386.disasm.i386RegOper
@@ -28,7 +26,7 @@ FAR_BRANCH_MASK = envi.BR_PROC | envi.BR_DEREF | envi.BR_ARCH
DESTRUCTIVE_MNEMONICS = ("mov", "lea", "pop", "xor")
def get_previous_instructions(vw: VivWorkspace, va: int) -> List[int]:
def get_previous_instructions(vw, va):
"""
collect the instructions that flow to the given address, local to the current function.
@@ -42,24 +40,22 @@ def get_previous_instructions(vw: VivWorkspace, va: int) -> List[int]:
ret = []
# find the immediate prior instruction.
# ensure that it falls through to this one.
# ensure that it fallsthrough to this one.
loc = vw.getPrevLocation(va, adjacent=True)
if loc is not None:
ploc = vw.getPrevLocation(va, adjacent=True)
if ploc is not None:
# from vivisect.const:
# location: (L_VA, L_SIZE, L_LTYPE, L_TINFO)
(pva, _, ptype, pinfo) = ploc
# from vivisect.const:
# location: (L_VA, L_SIZE, L_LTYPE, L_TINFO)
(pva, _, ptype, pinfo) = vw.getPrevLocation(va, adjacent=True)
if ptype == LOC_OP and not (pinfo & IF_NOFALL):
ret.append(pva)
if ptype == LOC_OP and not (pinfo & IF_NOFALL):
ret.append(pva)
# find any code refs, e.g. jmp, to this location.
# ignore any calls.
#
# from vivisect.const:
# xref: (XR_FROM, XR_TO, XR_RTYPE, XR_RFLAG)
for xfrom, _, _, xflag in vw.getXrefsTo(va, REF_CODE):
for (xfrom, _, _, xflag) in vw.getXrefsTo(va, REF_CODE):
if (xflag & FAR_BRANCH_MASK) != 0:
continue
ret.append(xfrom)
@@ -71,7 +67,7 @@ class NotFoundError(Exception):
pass
def find_definition(vw: VivWorkspace, va: int, reg: int) -> Tuple[int, Optional[int]]:
def find_definition(vw, va, reg):
"""
scan backwards from the given address looking for assignments to the given register.
if a constant, return that value.
@@ -87,8 +83,8 @@ def find_definition(vw: VivWorkspace, va: int, reg: int) -> Tuple[int, Optional[
raises:
NotFoundError: when the definition cannot be found.
"""
q: Deque[int] = collections.deque()
seen: Set[int] = set()
q = collections.deque()
seen = set([])
q.extend(get_previous_instructions(vw, va))
while q:
@@ -132,14 +128,14 @@ def find_definition(vw: VivWorkspace, va: int, reg: int) -> Tuple[int, Optional[
raise NotFoundError()
def is_indirect_call(vw: VivWorkspace, va: int, insn: envi.Opcode) -> bool:
def is_indirect_call(vw, va, insn=None):
if insn is None:
insn = vw.parseOpcode(va)
return insn.mnem in ("call", "jmp") and isinstance(insn.opers[0], envi.archs.i386.disasm.i386RegOper)
def resolve_indirect_call(vw: VivWorkspace, va: int, insn: envi.Opcode) -> Tuple[int, Optional[int]]:
def resolve_indirect_call(vw, va, insn=None):
"""
inspect the given indirect call instruction and attempt to resolve the target address.

View File

@@ -1,29 +1,26 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
from typing import List, Tuple, Callable, Iterator
import envi
import envi.exc
import viv_utils
import envi.memory
import viv_utils.flirt
import envi.archs.i386.regs
import envi.archs.amd64.regs
import envi.archs.i386.disasm
import envi.archs.amd64.disasm
import capa.features.extractors.helpers
import capa.features.extractors.viv.helpers
from capa.features.insn import API, MAX_STRUCTURE_SIZE, Number, Offset, Mnemonic, OperandNumber, OperandOffset
from capa.features.common import MAX_BYTES_FEATURE_SIZE, THUNK_CHAIN_DEPTH_DELTA, Bytes, String, Feature, Characteristic
from capa.features.address import Address, AbsoluteVirtualAddress
from capa.features.extractors.elf import SymTab
from capa.features.extractors.base_extractor import BBHandle, InsnHandle, FunctionHandle
from capa.features import (
ARCH_X32,
ARCH_X64,
MAX_BYTES_FEATURE_SIZE,
THUNK_CHAIN_DEPTH_DELTA,
Bytes,
String,
Characteristic,
)
from capa.features.insn import API, Number, Offset, Mnemonic
from capa.features.extractors.viv.indirect_calls import NotFoundError, resolve_indirect_call
# security cookie checks may perform non-zeroing XORs, these are expected within a certain
@@ -31,21 +28,27 @@ from capa.features.extractors.viv.indirect_calls import NotFoundError, resolve_i
SECURITY_COOKIE_BYTES_DELTA = 0x40
def interface_extract_instruction_XXX(
fh: FunctionHandle, bbh: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
def get_arch(vw):
arch = vw.getMeta("Architecture")
if arch == "i386":
return ARCH_X32
elif arch == "amd64":
return ARCH_X64
def interface_extract_instruction_XXX(f, bb, insn):
"""
parse features from the given instruction.
args:
fh: the function handle to process.
bbh: the basic block handle to process.
ih: the instruction handle to process.
f (viv_utils.Function): the function to process.
bb (viv_utils.BasicBlock): the basic block to process.
insn (vivisect...Instruction): the instruction to process.
yields:
(Feature, Address): the feature and the address at which its found.
(Feature, int): the feature and the address at which its found.
"""
raise NotImplementedError
yield NotImplementedError("feature"), NotImplementedError("virtual address")
def get_imports(vw):
@@ -65,15 +68,13 @@ def get_imports(vw):
return imports
def extract_insn_api_features(fh: FunctionHandle, bb, ih: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
"""
parse API features from the given instruction.
def extract_insn_api_features(f, bb, insn):
"""parse API features from the given instruction."""
# example:
#
# call dword [0x00473038]
example:
call dword [0x00473038]
"""
insn: envi.Opcode = ih.inner
f: viv_utils.Function = fh.inner
if insn.mnem not in ("call", "jmp"):
return
@@ -90,12 +91,12 @@ def extract_insn_api_features(fh: FunctionHandle, bb, ih: InsnHandle) -> Iterato
if target in imports:
dll, symbol = imports[target]
for name in capa.features.extractors.helpers.generate_symbols(dll, symbol):
yield API(name), ih.address
yield API(name), insn.va
# call via thunk on x86,
# see 9324d1a8ae37a36ae560c37448c9705a at 0x407985
#
# this is also how calls to internal functions may be decoded on x32 and x64.
# this is also how calls to internal functions may be decoded on x64.
# see Lab21-01.exe_:0x140001178
#
# follow chained thunks, e.g. in 82bf6347acf15e5d883715dc289d8a2b at 0x14005E0FF in
@@ -110,46 +111,11 @@ def extract_insn_api_features(fh: FunctionHandle, bb, ih: InsnHandle) -> Iterato
if not target:
return
if f.vw.metadata["Format"] == "elf":
if "symtab" not in fh.ctx["cache"]:
# the symbol table gets stored as a function's attribute in order to avoid running
# this code everytime the call is made, thus preventing the computational overhead.
try:
fh.ctx["cache"]["symtab"] = SymTab.from_viv(f.vw.parsedbin)
except Exception:
fh.ctx["cache"]["symtab"] = None
symtab = fh.ctx["cache"]["symtab"]
if symtab:
for symbol in symtab.get_symbols():
sym_name = symtab.get_name(symbol)
sym_value = symbol.value
sym_info = symbol.info
STT_FUNC = 0x2
if sym_value == target and sym_info & STT_FUNC != 0:
yield API(sym_name), ih.address
if viv_utils.flirt.is_library_function(f.vw, target):
name = viv_utils.get_function_name(f.vw, target)
yield API(name), ih.address
if name.startswith("_"):
# some linkers may prefix linked routines with a `_` to avoid name collisions.
# extract features for both the mangled and un-mangled representations.
# e.g. `_fwrite` -> `fwrite`
# see: https://stackoverflow.com/a/2628384/87207
yield API(name[1:]), ih.address
return
for _ in range(THUNK_CHAIN_DEPTH_DELTA):
if target in imports:
dll, symbol = imports[target]
for name in capa.features.extractors.helpers.generate_symbols(dll, symbol):
yield API(name), ih.address
# if jump leads to an ENDBRANCH instruction, skip it
if f.vw.getByteDef(target)[1].startswith(b"\xf3\x0f\x1e"):
target += 4
yield API(name), insn.va
target = capa.features.extractors.viv.helpers.get_coderef_from(f.vw, target)
if not target:
@@ -165,7 +131,7 @@ def extract_insn_api_features(fh: FunctionHandle, bb, ih: InsnHandle) -> Iterato
if target in imports:
dll, symbol = imports[target]
for name in capa.features.extractors.helpers.generate_symbols(dll, symbol):
yield API(name), ih.address
yield API(name), insn.va
elif isinstance(insn.opers[0], envi.archs.i386.disasm.i386RegOper):
try:
@@ -182,7 +148,38 @@ def extract_insn_api_features(fh: FunctionHandle, bb, ih: InsnHandle) -> Iterato
if target in imports:
dll, symbol = imports[target]
for name in capa.features.extractors.helpers.generate_symbols(dll, symbol):
yield API(name), ih.address
yield API(name), insn.va
def extract_insn_number_features(f, bb, insn):
"""parse number features from the given instruction."""
# example:
#
# push 3136B0h ; dwControlCode
for oper in insn.opers:
# this is for both x32 and x64
if not isinstance(oper, (envi.archs.i386.disasm.i386ImmOper, envi.archs.i386.disasm.i386ImmMemOper)):
continue
if isinstance(oper, envi.archs.i386.disasm.i386ImmOper):
v = oper.getOperValue(oper)
else:
v = oper.getOperAddr(oper)
if f.vw.probeMemory(v, 1, envi.memory.MM_READ):
# this is a valid address
# assume its not also a constant.
continue
if insn.mnem == "add" and insn.opers[0].isReg() and insn.opers[0].reg == envi.archs.i386.disasm.REG_ESP:
# skip things like:
#
# .text:00401140 call sub_407E2B
# .text:00401145 add esp, 0Ch
return
yield Number(v), insn.va
yield Number(v, arch=get_arch(f.vw)), insn.va
def derefs(vw, p):
@@ -196,13 +193,8 @@ def derefs(vw, p):
while True:
if not vw.isValidPointer(p):
return
yield p
if vw.isProbablyString(p) or vw.isProbablyUnicode(p):
# don't deref strings that coincidentally are pointers
return
try:
next = vw.readMemoryPtr(p)
except Exception:
@@ -222,7 +214,7 @@ def derefs(vw, p):
p = next
def read_memory(vw, va: int, size: int) -> bytes:
def read_memory(vw, va, size):
# as documented in #176, vivisect will not readMemory() when the section is not marked readable.
#
# but here, we don't care about permissions.
@@ -235,10 +227,10 @@ def read_memory(vw, va: int, size: int) -> bytes:
mva, msize, mperms, mfname = mmap
offset = va - mva
return mbytes[offset : offset + size]
raise envi.exc.SegmentationViolation(va)
raise envi.SegmentationViolation(va)
def read_bytes(vw, va: int) -> bytes:
def read_bytes(vw, va):
"""
read up to MAX_BYTES_FEATURE_SIZE from the given address.
@@ -247,7 +239,7 @@ def read_bytes(vw, va: int) -> bytes:
"""
segm = vw.getSegment(va)
if not segm:
raise envi.exc.SegmentationViolation(va)
raise envi.SegmentationViolation(va)
segm_end = segm[0] + segm[1]
try:
@@ -256,19 +248,16 @@ def read_bytes(vw, va: int) -> bytes:
return read_memory(vw, va, segm_end - va)
else:
return read_memory(vw, va, MAX_BYTES_FEATURE_SIZE)
except envi.exc.SegmentationViolation:
except envi.SegmentationViolation:
raise
def extract_insn_bytes_features(fh: FunctionHandle, bb, ih: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
def extract_insn_bytes_features(f, bb, insn):
"""
parse byte sequence features from the given instruction.
example:
# push offset iid_004118d4_IShellLinkA ; riid
"""
insn: envi.Opcode = ih.inner
f: viv_utils.Function = fh.inner
if insn.mnem == "call":
return
@@ -288,39 +277,30 @@ def extract_insn_bytes_features(fh: FunctionHandle, bb, ih: InsnHandle) -> Itera
else:
continue
for vv in derefs(f.vw, v):
for v in derefs(f.vw, v):
try:
buf = read_bytes(f.vw, vv)
except envi.exc.SegmentationViolation:
buf = read_bytes(f.vw, v)
except envi.SegmentationViolation:
continue
if capa.features.extractors.helpers.all_zeros(buf):
continue
if f.vw.isProbablyString(vv) or f.vw.isProbablyUnicode(vv):
# don't extract byte features for obvious strings
continue
yield Bytes(buf), ih.address
yield Bytes(buf), insn.va
def read_string(vw, offset: int) -> str:
def read_string(vw, offset):
try:
alen = vw.detectString(offset)
except envi.exc.SegmentationViolation:
except envi.SegmentationViolation:
pass
else:
if alen > 0:
buf = read_memory(vw, offset, alen)
if b"\x00" in buf:
# account for bug #1271.
# remove when vivisect is fixed.
buf = buf.partition(b"\x00")[0]
return buf.decode("utf-8")
return read_memory(vw, offset, alen).decode("utf-8")
try:
ulen = vw.detectUnicode(offset)
except envi.exc.SegmentationViolation:
except envi.SegmentationViolation:
pass
except IndexError:
# potential vivisect bug detecting Unicode at segment end
@@ -335,24 +315,92 @@ def read_string(vw, offset: int) -> str:
# vivisect seems to mis-detect the end unicode strings
# off by two, too short
ulen += 2
# partition to account for bug #1271.
# remove when vivisect is fixed.
return read_memory(vw, offset, ulen).decode("utf-16").partition("\x00")[0]
return read_memory(vw, offset, ulen).decode("utf-16")
raise ValueError("not a string", offset)
def is_security_cookie(f, bb, insn) -> bool:
def extract_insn_string_features(f, bb, insn):
"""parse string features from the given instruction."""
# example:
#
# push offset aAcr ; "ACR > "
for oper in insn.opers:
if isinstance(oper, envi.archs.i386.disasm.i386ImmOper):
v = oper.getOperValue(oper)
elif isinstance(oper, envi.archs.i386.disasm.i386ImmMemOper):
# like 0x10056CB4 in `lea eax, dword [0x10056CB4]`
v = oper.imm
elif isinstance(oper, envi.archs.i386.disasm.i386SibOper):
# like 0x401000 in `mov eax, 0x401000[2 * ebx]`
v = oper.imm
elif isinstance(oper, envi.archs.amd64.disasm.Amd64RipRelOper):
v = oper.getOperAddr(insn)
else:
continue
for v in derefs(f.vw, v):
try:
s = read_string(f.vw, v)
except ValueError:
continue
else:
yield String(s.rstrip("\x00")), insn.va
def extract_insn_offset_features(f, bb, insn):
"""parse structure offset features from the given instruction."""
# example:
#
# .text:0040112F cmp [esi+4], ebx
for oper in insn.opers:
# this is for both x32 and x64
# like [esi + 4]
# reg ^
# disp
if isinstance(oper, envi.archs.i386.disasm.i386RegMemOper):
if oper.reg == envi.archs.i386.disasm.REG_ESP:
continue
if oper.reg == envi.archs.i386.disasm.REG_EBP:
continue
# TODO: do x64 support for real.
if oper.reg == envi.archs.amd64.disasm.REG_RBP:
continue
# viv already decodes offsets as signed
v = oper.disp
yield Offset(v), insn.va
yield Offset(v, arch=get_arch(f.vw)), insn.va
# like: [esi + ecx + 16384]
# reg ^ ^
# index ^
# disp
elif isinstance(oper, envi.archs.i386.disasm.i386SibOper):
# viv already decodes offsets as signed
v = oper.disp
yield Offset(v), insn.va
yield Offset(v, arch=get_arch(f.vw)), insn.va
def is_security_cookie(f, bb, insn):
"""
check if an instruction is related to security cookie checks
"""
# security cookie check should use SP or BP
oper = insn.opers[1]
if oper.isReg() and oper.reg not in [
envi.archs.i386.regs.REG_ESP,
envi.archs.i386.regs.REG_EBP,
envi.archs.amd64.regs.REG_RBP,
envi.archs.amd64.regs.REG_RSP,
envi.archs.i386.disasm.REG_ESP,
envi.archs.i386.disasm.REG_EBP,
# TODO: do x64 support for real.
envi.archs.amd64.disasm.REG_RBP,
envi.archs.amd64.disasm.REG_RSP,
]:
return False
@@ -369,17 +417,11 @@ def is_security_cookie(f, bb, insn) -> bool:
return False
def extract_insn_nzxor_characteristic_features(
fh: FunctionHandle, bbhandle: BBHandle, ih: InsnHandle
) -> Iterator[Tuple[Feature, Address]]:
def extract_insn_nzxor_characteristic_features(f, bb, insn):
"""
parse non-zeroing XOR instruction from the given instruction.
ignore expected non-zeroing XORs, e.g. security cookies.
"""
insn: envi.Opcode = ih.inner
bb: viv_utils.BasicBlock = bbhandle.inner
f: viv_utils.Function = fh.inner
if insn.mnem not in ("xor", "xorpd", "xorps", "pxor"):
return
@@ -389,37 +431,19 @@ def extract_insn_nzxor_characteristic_features(
if is_security_cookie(f, bb, insn):
return
yield Characteristic("nzxor"), ih.address
yield Characteristic("nzxor"), insn.va
def extract_insn_mnemonic_features(f, bb, ih: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
def extract_insn_mnemonic_features(f, bb, insn):
"""parse mnemonic features from the given instruction."""
yield Mnemonic(ih.inner.mnem), ih.address
yield Mnemonic(insn.mnem), insn.va
def extract_insn_obfs_call_plus_5_characteristic_features(f, bb, ih: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
"""
parse call $+5 instruction from the given instruction.
"""
insn: envi.Opcode = ih.inner
if insn.mnem != "call":
return
if isinstance(insn.opers[0], envi.archs.i386.disasm.i386PcRelOper):
if insn.va + 5 == insn.opers[0].getOperValue(insn):
yield Characteristic("call $+5"), ih.address
if isinstance(insn.opers[0], (envi.archs.i386.disasm.i386ImmMemOper, envi.archs.amd64.disasm.Amd64RipRelOper)):
if insn.va + 5 == insn.opers[0].getOperAddr(insn):
yield Characteristic("call $+5"), ih.address
def extract_insn_peb_access_characteristic_features(f, bb, ih: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
def extract_insn_peb_access_characteristic_features(f, bb, insn):
"""
parse peb access from the given function. fs:[0x30] on x86, gs:[0x60] on x64
"""
insn: envi.Opcode = ih.inner
# TODO handle where fs/gs are loaded into a register or onto the stack and used later
if insn.mnem not in ["push", "mov"]:
return
@@ -438,7 +462,7 @@ def extract_insn_peb_access_characteristic_features(f, bb, ih: InsnHandle) -> It
if (isinstance(oper, envi.archs.i386.disasm.i386RegMemOper) and oper.disp == 0x30) or (
isinstance(oper, envi.archs.i386.disasm.i386ImmMemOper) and oper.imm == 0x30
):
yield Characteristic("peb access"), ih.address
yield Characteristic("peb access"), insn.va
elif "gs" in prefix:
for oper in insn.opers:
if (
@@ -446,25 +470,23 @@ def extract_insn_peb_access_characteristic_features(f, bb, ih: InsnHandle) -> It
or (isinstance(oper, envi.archs.amd64.disasm.i386SibOper) and oper.imm == 0x60)
or (isinstance(oper, envi.archs.amd64.disasm.i386ImmMemOper) and oper.imm == 0x60)
):
yield Characteristic("peb access"), ih.address
yield Characteristic("peb access"), insn.va
else:
pass
def extract_insn_segment_access_features(f, bb, ih: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
"""parse the instruction for access to fs or gs"""
insn: envi.Opcode = ih.inner
def extract_insn_segment_access_features(f, bb, insn):
""" parse the instruction for access to fs or gs """
prefix = insn.getPrefixName()
if prefix == "fs":
yield Characteristic("fs access"), ih.address
yield Characteristic("fs access"), insn.va
if prefix == "gs":
yield Characteristic("gs access"), ih.address
yield Characteristic("gs access"), insn.va
def get_section(vw, va: int):
def get_section(vw, va):
for start, length, _, __ in vw.getMemoryMaps():
if start <= va < start + length:
return start
@@ -472,13 +494,10 @@ def get_section(vw, va: int):
raise KeyError(va)
def extract_insn_cross_section_cflow(fh: FunctionHandle, bb, ih: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
def extract_insn_cross_section_cflow(f, bb, insn):
"""
inspect the instruction for a CALL or JMP that crosses section boundaries.
"""
insn: envi.Opcode = ih.inner
f: viv_utils.Function = fh.inner
for va, flags in insn.getBranches():
if va is None:
# va may be none for dynamic branches that haven't been resolved, such as `jmp eax`.
@@ -505,7 +524,7 @@ def extract_insn_cross_section_cflow(fh: FunctionHandle, bb, ih: InsnHandle) ->
continue
if get_section(f.vw, insn.va) != get_section(f.vw, va):
yield Characteristic("cross section flow"), ih.address
yield Characteristic("cross section flow"), insn.va
except KeyError:
continue
@@ -513,10 +532,7 @@ def extract_insn_cross_section_cflow(fh: FunctionHandle, bb, ih: InsnHandle) ->
# this is a feature that's most relevant at the function scope,
# however, its most efficient to extract at the instruction scope.
def extract_function_calls_from(fh: FunctionHandle, bb, ih: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
insn: envi.Opcode = ih.inner
f: viv_utils.Function = fh.inner
def extract_function_calls_from(f, bb, insn):
if insn.mnem != "call":
return
@@ -526,8 +542,7 @@ def extract_function_calls_from(fh: FunctionHandle, bb, ih: InsnHandle) -> Itera
if isinstance(insn.opers[0], envi.archs.i386.disasm.i386ImmMemOper):
oper = insn.opers[0]
target = oper.getOperAddr(insn)
if target >= 0:
yield Characteristic("calls from"), AbsoluteVirtualAddress(target)
yield Characteristic("calls from"), target
# call via thunk on x86,
# see 9324d1a8ae37a36ae560c37448c9705a at 0x407985
@@ -536,192 +551,43 @@ def extract_function_calls_from(fh: FunctionHandle, bb, ih: InsnHandle) -> Itera
# see Lab21-01.exe_:0x140001178
elif isinstance(insn.opers[0], envi.archs.i386.disasm.i386PcRelOper):
target = insn.opers[0].getOperValue(insn)
if target >= 0:
yield Characteristic("calls from"), AbsoluteVirtualAddress(target)
yield Characteristic("calls from"), target
# call via IAT, x64
elif isinstance(insn.opers[0], envi.archs.amd64.disasm.Amd64RipRelOper):
op = insn.opers[0]
target = op.getOperAddr(insn)
if target >= 0:
yield Characteristic("calls from"), AbsoluteVirtualAddress(target)
yield Characteristic("calls from"), target
if target and target == f.va:
# if we found a jump target and it's the function address
# mark as recursive
yield Characteristic("recursive call"), AbsoluteVirtualAddress(target)
yield Characteristic("recursive call"), target
# this is a feature that's most relevant at the function or basic block scope,
# however, its most efficient to extract at the instruction scope.
def extract_function_indirect_call_characteristic_features(f, bb, ih: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
def extract_function_indirect_call_characteristic_features(f, bb, insn):
"""
extract indirect function call characteristic (e.g., call eax or call dword ptr [edx+4])
does not include calls like => call ds:dword_ABD4974
"""
insn: envi.Opcode = ih.inner
if insn.mnem != "call":
return
# Checks below work for x86 and x64
if isinstance(insn.opers[0], envi.archs.i386.disasm.i386RegOper):
# call edx
yield Characteristic("indirect call"), ih.address
yield Characteristic("indirect call"), insn.va
elif isinstance(insn.opers[0], envi.archs.i386.disasm.i386RegMemOper):
# call dword ptr [eax+50h]
yield Characteristic("indirect call"), ih.address
yield Characteristic("indirect call"), insn.va
elif isinstance(insn.opers[0], envi.archs.i386.disasm.i386SibOper):
# call qword ptr [rsp+78h]
yield Characteristic("indirect call"), ih.address
yield Characteristic("indirect call"), insn.va
def extract_op_number_features(
fh: FunctionHandle, bb, ih: InsnHandle, i, oper: envi.Operand
) -> Iterator[Tuple[Feature, Address]]:
"""parse number features from the given operand.
example:
push 3136B0h ; dwControlCode
"""
insn: envi.Opcode = ih.inner
f: viv_utils.Function = fh.inner
# this is for both x32 and x64
if not isinstance(oper, (envi.archs.i386.disasm.i386ImmOper, envi.archs.i386.disasm.i386ImmMemOper)):
return
if isinstance(oper, envi.archs.i386.disasm.i386ImmOper):
v = oper.getOperValue(oper)
else:
v = oper.getOperAddr(oper)
if f.vw.probeMemory(v, 1, envi.memory.MM_READ):
# this is a valid address
# assume its not also a constant.
return
if insn.mnem == "add" and insn.opers[0].isReg() and insn.opers[0].reg == envi.archs.i386.regs.REG_ESP:
# skip things like:
#
# .text:00401140 call sub_407E2B
# .text:00401145 add esp, 0Ch
return
yield Number(v), ih.address
yield OperandNumber(i, v), ih.address
if insn.mnem == "add" and 0 < v < MAX_STRUCTURE_SIZE and isinstance(oper, envi.archs.i386.disasm.i386ImmOper):
# for pattern like:
#
# add eax, 0x10
#
# assume 0x10 is also an offset (imagine eax is a pointer).
yield Offset(v), ih.address
yield OperandOffset(i, v), ih.address
def extract_op_offset_features(
fh: FunctionHandle, bb, ih: InsnHandle, i, oper: envi.Operand
) -> Iterator[Tuple[Feature, Address]]:
"""parse structure offset features from the given operand."""
# example:
#
# .text:0040112F cmp [esi+4], ebx
insn: envi.Opcode = ih.inner
f: viv_utils.Function = fh.inner
# this is for both x32 and x64
# like [esi + 4]
# reg ^
# disp
if isinstance(oper, envi.archs.i386.disasm.i386RegMemOper):
if oper.reg == envi.archs.i386.regs.REG_ESP:
return
if oper.reg == envi.archs.i386.regs.REG_EBP:
return
if oper.reg == envi.archs.amd64.regs.REG_RBP:
return
# viv already decodes offsets as signed
v = oper.disp
yield Offset(v), ih.address
yield OperandOffset(i, v), ih.address
if insn.mnem == "lea" and i == 1 and not f.vw.probeMemory(v, 1, envi.memory.MM_READ):
# for pattern like:
#
# lea eax, [ebx + 1]
#
# assume 1 is also an offset (imagine ebx is a zero register).
yield Number(v), ih.address
yield OperandNumber(i, v), ih.address
# like: [esi + ecx + 16384]
# reg ^ ^
# index ^
# disp
elif isinstance(oper, envi.archs.i386.disasm.i386SibOper):
# viv already decodes offsets as signed
v = oper.disp
yield Offset(v), ih.address
yield OperandOffset(i, v), ih.address
def extract_op_string_features(
fh: FunctionHandle, bb, ih: InsnHandle, i, oper: envi.Operand
) -> Iterator[Tuple[Feature, Address]]:
"""parse string features from the given operand."""
# example:
#
# push offset aAcr ; "ACR > "
insn: envi.Opcode = ih.inner
f: viv_utils.Function = fh.inner
if isinstance(oper, envi.archs.i386.disasm.i386ImmOper):
v = oper.getOperValue(oper)
elif isinstance(oper, envi.archs.i386.disasm.i386ImmMemOper):
# like 0x10056CB4 in `lea eax, dword [0x10056CB4]`
v = oper.imm
elif isinstance(oper, envi.archs.i386.disasm.i386SibOper):
# like 0x401000 in `mov eax, 0x401000[2 * ebx]`
v = oper.imm
elif isinstance(oper, envi.archs.amd64.disasm.Amd64RipRelOper):
v = oper.getOperAddr(insn)
else:
return
for vv in derefs(f.vw, v):
try:
s = read_string(f.vw, vv).rstrip("\x00")
except ValueError:
continue
else:
if len(s) >= 4:
yield String(s), ih.address
def extract_operand_features(f: FunctionHandle, bb, insn: InsnHandle) -> Iterator[Tuple[Feature, Address]]:
for i, oper in enumerate(insn.inner.opers):
for op_handler in OPERAND_HANDLERS:
for feature, addr in op_handler(f, bb, insn, i, oper):
yield feature, addr
OPERAND_HANDLERS: List[
Callable[[FunctionHandle, BBHandle, InsnHandle, int, envi.Operand], Iterator[Tuple[Feature, Address]]]
] = [
extract_op_number_features,
extract_op_offset_features,
extract_op_string_features,
]
def extract_features(f, bb, insn) -> Iterator[Tuple[Feature, Address]]:
def extract_features(f, bb, insn):
"""
extract features from the given insn.
@@ -731,23 +597,24 @@ def extract_features(f, bb, insn) -> Iterator[Tuple[Feature, Address]]:
insn (vivisect...Instruction): the instruction to process.
yields:
Tuple[Feature, Address]: the features and their location found in this insn.
Feature, set[VA]: the features and their location found in this insn.
"""
for insn_handler in INSTRUCTION_HANDLERS:
for feature, addr in insn_handler(f, bb, insn):
yield feature, addr
for feature, va in insn_handler(f, bb, insn):
yield feature, va
INSTRUCTION_HANDLERS: List[Callable[[FunctionHandle, BBHandle, InsnHandle], Iterator[Tuple[Feature, Address]]]] = [
INSTRUCTION_HANDLERS = (
extract_insn_api_features,
extract_insn_number_features,
extract_insn_string_features,
extract_insn_bytes_features,
extract_insn_offset_features,
extract_insn_nzxor_characteristic_features,
extract_insn_mnemonic_features,
extract_insn_obfs_call_plus_5_characteristic_features,
extract_insn_peb_access_characteristic_features,
extract_insn_cross_section_cflow,
extract_insn_segment_access_features,
extract_function_calls_from,
extract_function_indirect_call_characteristic_features,
extract_operand_features,
]
)

View File

@@ -1,4 +1,4 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
@@ -6,33 +6,22 @@
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
from capa.features.common import Feature
from capa.features import Feature
class Export(Feature):
def __init__(self, value: str, description=None):
def __init__(self, value, description=None):
# value is export name
super().__init__(value, description=description)
super(Export, self).__init__(value, description=description)
class Import(Feature):
def __init__(self, value: str, description=None):
def __init__(self, value, description=None):
# value is import name
super().__init__(value, description=description)
super(Import, self).__init__(value, description=description)
class Section(Feature):
def __init__(self, value: str, description=None):
def __init__(self, value, description=None):
# value is section name
super().__init__(value, description=description)
class FunctionName(Feature):
"""recognized name for statically linked function"""
def __init__(self, name: str, description=None):
# value is function name
super().__init__(name, description=description)
# override the name property set by `capa.features.Feature`
# that would be `functionname` (note missing dash)
self.name = "function-name"
super(Section, self).__init__(value, description=description)

299
capa/features/freeze.py Normal file
View File

@@ -0,0 +1,299 @@
"""
capa freeze file format: `| capa0000 | + zlib(utf-8(json(...)))`
json format:
{
'version': 1,
'base address': int(base address),
'functions': {
int(function va): {
'basic blocks': {
int(basic block va): {
'instructions': [instruction va, ...]
},
...
},
...
},
...
},
'scopes': {
'file': [
(str(name), [any(arg), ...], int(va), ()),
...
},
'function': [
(str(name), [any(arg), ...], int(va), (int(function va), )),
...
],
'basic block': [
(str(name), [any(arg), ...], int(va), (int(function va),
int(basic block va))),
...
],
'instruction': [
(str(name), [any(arg), ...], int(va), (int(function va),
int(basic block va),
int(instruction va))),
...
],
}
}
Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at: [package root]/LICENSE.txt
Unless required by applicable law or agreed to in writing, software distributed under the License
is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and limitations under the License.
"""
import json
import zlib
import logging
import capa.features
import capa.features.file
import capa.features.insn
import capa.features.basicblock
import capa.features.extractors
from capa.helpers import hex
logger = logging.getLogger(__name__)
def serialize_feature(feature):
return feature.freeze_serialize()
KNOWN_FEATURES = {F.__name__: F for F in capa.features.Feature.__subclasses__()}
def deserialize_feature(doc):
F = KNOWN_FEATURES[doc[0]]
return F.freeze_deserialize(doc[1])
def dumps(extractor):
"""
serialize the given extractor to a string
args:
extractor: capa.features.extractor.FeatureExtractor:
returns:
str: the serialized features.
"""
ret = {
"version": 1,
"base address": extractor.get_base_address(),
"functions": {},
"scopes": {
"file": [],
"function": [],
"basic block": [],
"instruction": [],
},
}
for feature, va in extractor.extract_file_features():
ret["scopes"]["file"].append(serialize_feature(feature) + (hex(va), ()))
for f in extractor.get_functions():
ret["functions"][hex(f)] = {}
for feature, va in extractor.extract_function_features(f):
ret["scopes"]["function"].append(serialize_feature(feature) + (hex(va), (hex(f),)))
for bb in extractor.get_basic_blocks(f):
ret["functions"][hex(f)][hex(bb)] = []
for feature, va in extractor.extract_basic_block_features(f, bb):
ret["scopes"]["basic block"].append(
serialize_feature(feature)
+ (
hex(va),
(
hex(f),
hex(bb),
),
)
)
for insnva, insn in sorted(
[(insn.__int__(), insn) for insn in extractor.get_instructions(f, bb)], key=lambda p: p[0]
):
ret["functions"][hex(f)][hex(bb)].append(hex(insnva))
for feature, va in extractor.extract_insn_features(f, bb, insn):
ret["scopes"]["instruction"].append(
serialize_feature(feature)
+ (
hex(va),
(
hex(f),
hex(bb),
hex(insnva),
),
)
)
return json.dumps(ret)
def loads(s):
"""deserialize a set of features (as a NullFeatureExtractor) from a string."""
doc = json.loads(s)
if doc.get("version") != 1:
raise ValueError("unsupported freeze format version: %d" % (doc.get("version")))
features = {
"base address": doc.get("base address"),
"file features": [],
"functions": {},
}
for fva, function in doc.get("functions", {}).items():
fva = int(fva, 0x10)
features["functions"][fva] = {
"features": [],
"basic blocks": {},
}
for bbva, bb in function.items():
bbva = int(bbva, 0x10)
features["functions"][fva]["basic blocks"][bbva] = {
"features": [],
"instructions": {},
}
for insnva in bb:
insnva = int(insnva, 0x10)
features["functions"][fva]["basic blocks"][bbva]["instructions"][insnva] = {
"features": [],
}
# in the following blocks, each entry looks like:
#
# ('MatchedRule', ('foo', ), '0x401000', ('0x401000', ))
# ^^^^^^^^^^^^^ ^^^^^^^^^ ^^^^^^^^^^ ^^^^^^^^^^^^^^
# feature name args addr func/bb/insn
for feature in doc.get("scopes", {}).get("file", []):
va, loc = feature[2:]
va = int(va, 0x10)
feature = deserialize_feature(feature[:2])
features["file features"].append((va, feature))
for feature in doc.get("scopes", {}).get("function", []):
# fetch the pair like:
#
# ('0x401000', ('0x401000', ))
# ^^^^^^^^^^ ^^^^^^^^^^^^^^
# addr func/bb/insn
va, loc = feature[2:]
va = int(va, 0x10)
loc = [int(lo, 0x10) for lo in loc]
# decode the feature from the pair like:
#
# ('MatchedRule', ('foo', ))
# ^^^^^^^^^^^^^ ^^^^^^^^^
# feature name args
feature = deserialize_feature(feature[:2])
features["functions"][loc[0]]["features"].append((va, feature))
for feature in doc.get("scopes", {}).get("basic block", []):
va, loc = feature[2:]
va = int(va, 0x10)
loc = [int(lo, 0x10) for lo in loc]
feature = deserialize_feature(feature[:2])
features["functions"][loc[0]]["basic blocks"][loc[1]]["features"].append((va, feature))
for feature in doc.get("scopes", {}).get("instruction", []):
va, loc = feature[2:]
va = int(va, 0x10)
loc = [int(lo, 0x10) for lo in loc]
feature = deserialize_feature(feature[:2])
features["functions"][loc[0]]["basic blocks"][loc[1]]["instructions"][loc[2]]["features"].append((va, feature))
return capa.features.extractors.NullFeatureExtractor(features)
MAGIC = "capa0000".encode("ascii")
def dump(extractor):
"""serialize the given extractor to a byte array."""
return MAGIC + zlib.compress(dumps(extractor).encode("utf-8"))
def is_freeze(buf):
return buf[: len(MAGIC)] == MAGIC
def load(buf):
"""deserialize a set of features (as a NullFeatureExtractor) from a byte array."""
if not is_freeze(buf):
raise ValueError("missing magic header")
return loads(zlib.decompress(buf[len(MAGIC) :]).decode("utf-8"))
def main(argv=None):
import sys
import argparse
import capa.main
if argv is None:
argv = sys.argv[1:]
formats = [
("auto", "(default) detect file type automatically"),
("pe", "Windows PE file"),
("sc32", "32-bit shellcode"),
("sc64", "64-bit shellcode"),
]
format_help = ", ".join(["%s: %s" % (f[0], f[1]) for f in formats])
parser = argparse.ArgumentParser(description="save capa features to a file")
parser.add_argument("sample", type=str, help="Path to sample to analyze")
parser.add_argument("output", type=str, help="Path to output file")
parser.add_argument("-v", "--verbose", action="store_true", help="Enable verbose output")
parser.add_argument("-q", "--quiet", action="store_true", help="Disable all output but errors")
parser.add_argument(
"-f", "--format", choices=[f[0] for f in formats], default="auto", help="Select sample format, %s" % format_help
)
if sys.version_info >= (3, 0):
parser.add_argument(
"-b",
"--backend",
type=str,
help="select the backend to use",
choices=(capa.main.BACKEND_VIV, capa.main.BACKEND_SMDA),
default=capa.main.BACKEND_VIV,
)
args = parser.parse_args(args=argv)
if args.quiet:
logging.basicConfig(level=logging.ERROR)
logging.getLogger().setLevel(logging.ERROR)
elif args.verbose:
logging.basicConfig(level=logging.DEBUG)
logging.getLogger().setLevel(logging.DEBUG)
else:
logging.basicConfig(level=logging.INFO)
logging.getLogger().setLevel(logging.INFO)
backend = args.backend if sys.version_info > (3, 0) else capa.main.BACKEND_VIV
extractor = capa.main.get_extractor(args.sample, args.format, backend)
with open(args.output, "wb") as f:
f.write(dump(extractor))
return 0
if __name__ == "__main__":
import sys
sys.exit(main())

View File

@@ -1,399 +0,0 @@
"""
capa freeze file format: `| capa0000 | + zlib(utf-8(json(...)))`
Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at: [package root]/LICENSE.txt
Unless required by applicable law or agreed to in writing, software distributed under the License
is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and limitations under the License.
"""
import zlib
import logging
from enum import Enum
from typing import List, Tuple, Union
from pydantic import Field, BaseModel, ConfigDict
import capa.helpers
import capa.version
import capa.features.file
import capa.features.insn
import capa.features.common
import capa.features.address
import capa.features.basicblock
import capa.features.extractors.base_extractor
from capa.helpers import assert_never
from capa.features.freeze.features import Feature, feature_from_capa
logger = logging.getLogger(__name__)
class HashableModel(BaseModel):
model_config = ConfigDict(frozen=True)
class AddressType(str, Enum):
ABSOLUTE = "absolute"
RELATIVE = "relative"
FILE = "file"
DN_TOKEN = "dn token"
DN_TOKEN_OFFSET = "dn token offset"
NO_ADDRESS = "no address"
class Address(HashableModel):
type: AddressType
value: Union[int, Tuple[int, int], None] = None # None default value to support deserialization of NO_ADDRESS
@classmethod
def from_capa(cls, a: capa.features.address.Address) -> "Address":
if isinstance(a, capa.features.address.AbsoluteVirtualAddress):
return cls(type=AddressType.ABSOLUTE, value=int(a))
elif isinstance(a, capa.features.address.RelativeVirtualAddress):
return cls(type=AddressType.RELATIVE, value=int(a))
elif isinstance(a, capa.features.address.FileOffsetAddress):
return cls(type=AddressType.FILE, value=int(a))
elif isinstance(a, capa.features.address.DNTokenAddress):
return cls(type=AddressType.DN_TOKEN, value=int(a))
elif isinstance(a, capa.features.address.DNTokenOffsetAddress):
return cls(type=AddressType.DN_TOKEN_OFFSET, value=(a.token, a.offset))
elif a == capa.features.address.NO_ADDRESS or isinstance(a, capa.features.address._NoAddress):
return cls(type=AddressType.NO_ADDRESS, value=None)
elif isinstance(a, capa.features.address.Address) and not issubclass(type(a), capa.features.address.Address):
raise ValueError("don't use an Address instance directly")
elif isinstance(a, capa.features.address.Address):
raise ValueError("don't use an Address instance directly")
else:
assert_never(a)
def to_capa(self) -> capa.features.address.Address:
if self.type is AddressType.ABSOLUTE:
assert isinstance(self.value, int)
return capa.features.address.AbsoluteVirtualAddress(self.value)
elif self.type is AddressType.RELATIVE:
assert isinstance(self.value, int)
return capa.features.address.RelativeVirtualAddress(self.value)
elif self.type is AddressType.FILE:
assert isinstance(self.value, int)
return capa.features.address.FileOffsetAddress(self.value)
elif self.type is AddressType.DN_TOKEN:
assert isinstance(self.value, int)
return capa.features.address.DNTokenAddress(self.value)
elif self.type is AddressType.DN_TOKEN_OFFSET:
assert isinstance(self.value, tuple)
token, offset = self.value
assert isinstance(token, int)
assert isinstance(offset, int)
return capa.features.address.DNTokenOffsetAddress(token, offset)
elif self.type is AddressType.NO_ADDRESS:
return capa.features.address.NO_ADDRESS
else:
assert_never(self.type)
def __lt__(self, other: "Address") -> bool:
if self.type != other.type:
return self.type < other.type
if self.type is AddressType.NO_ADDRESS:
return True
else:
assert self.type == other.type
# mypy doesn't realize we've proven that either
# both are ints, or both are tuples of ints.
# and both of these are comparable.
return self.value < other.value # type: ignore
class GlobalFeature(HashableModel):
feature: Feature
class FileFeature(HashableModel):
address: Address
feature: Feature
class FunctionFeature(HashableModel):
"""
args:
function: the address of the function to which this feature belongs.
address: the address at which this feature is found.
function != address because, e.g., the feature may be found *within* the scope (function).
versus right at its starting address.
"""
function: Address
address: Address
feature: Feature
class BasicBlockFeature(HashableModel):
"""
args:
basic_block: the address of the basic block to which this feature belongs.
address: the address at which this feature is found.
basic_block != address because, e.g., the feature may be found *within* the scope (basic block).
versus right at its starting address.
"""
basic_block: Address = Field(alias="basic block")
address: Address
feature: Feature
model_config = ConfigDict(populate_by_name=True)
class InstructionFeature(HashableModel):
"""
args:
instruction: the address of the instruction to which this feature belongs.
address: the address at which this feature is found.
instruction != address because, e.g., the feature may be found *within* the scope (basic block),
versus right at its starting address.
"""
instruction: Address
address: Address
feature: Feature
class InstructionFeatures(BaseModel):
address: Address
features: Tuple[InstructionFeature, ...]
class BasicBlockFeatures(BaseModel):
address: Address
features: Tuple[BasicBlockFeature, ...]
instructions: Tuple[InstructionFeatures, ...]
class FunctionFeatures(BaseModel):
address: Address
features: Tuple[FunctionFeature, ...]
basic_blocks: Tuple[BasicBlockFeatures, ...] = Field(alias="basic blocks")
model_config = ConfigDict(populate_by_name=True)
class Features(BaseModel):
global_: Tuple[GlobalFeature, ...] = Field(alias="global")
file: Tuple[FileFeature, ...]
functions: Tuple[FunctionFeatures, ...]
model_config = ConfigDict(populate_by_name=True)
class Extractor(BaseModel):
name: str
version: str = capa.version.__version__
model_config = ConfigDict(populate_by_name=True)
class Freeze(BaseModel):
version: int = 2
base_address: Address = Field(alias="base address")
extractor: Extractor
features: Features
model_config = ConfigDict(populate_by_name=True)
def dumps(extractor: capa.features.extractors.base_extractor.FeatureExtractor) -> str:
"""
serialize the given extractor to a string
"""
global_features: List[GlobalFeature] = []
for feature, _ in extractor.extract_global_features():
global_features.append(
GlobalFeature(
feature=feature_from_capa(feature),
)
)
file_features: List[FileFeature] = []
for feature, address in extractor.extract_file_features():
file_features.append(
FileFeature(
feature=feature_from_capa(feature),
address=Address.from_capa(address),
)
)
function_features: List[FunctionFeatures] = []
for f in extractor.get_functions():
faddr = Address.from_capa(f.address)
ffeatures = [
FunctionFeature(
function=faddr,
address=Address.from_capa(addr),
feature=feature_from_capa(feature),
)
for feature, addr in extractor.extract_function_features(f)
]
basic_blocks = []
for bb in extractor.get_basic_blocks(f):
bbaddr = Address.from_capa(bb.address)
bbfeatures = [
BasicBlockFeature(
basic_block=bbaddr,
address=Address.from_capa(addr),
feature=feature_from_capa(feature),
) # type: ignore
# Mypy is unable to recognise `basic_block` as a argument due to alias
for feature, addr in extractor.extract_basic_block_features(f, bb)
]
instructions = []
for insn in extractor.get_instructions(f, bb):
iaddr = Address.from_capa(insn.address)
ifeatures = [
InstructionFeature(
instruction=iaddr,
address=Address.from_capa(addr),
feature=feature_from_capa(feature),
)
for feature, addr in extractor.extract_insn_features(f, bb, insn)
]
instructions.append(
InstructionFeatures(
address=iaddr,
features=tuple(ifeatures),
)
)
basic_blocks.append(
BasicBlockFeatures(
address=bbaddr,
features=tuple(bbfeatures),
instructions=tuple(instructions),
)
)
function_features.append(
FunctionFeatures(
address=faddr,
features=tuple(ffeatures),
basic_blocks=basic_blocks,
) # type: ignore
# Mypy is unable to recognise `basic_blocks` as a argument due to alias
)
features = Features(
global_=global_features,
file=tuple(file_features),
functions=tuple(function_features),
) # type: ignore
# Mypy is unable to recognise `global_` as a argument due to alias
freeze = Freeze(
version=2,
base_address=Address.from_capa(extractor.get_base_address()),
extractor=Extractor(name=extractor.__class__.__name__),
features=features,
) # type: ignore
# Mypy is unable to recognise `base_address` as a argument due to alias
return freeze.model_dump_json()
def loads(s: str) -> capa.features.extractors.base_extractor.FeatureExtractor:
"""deserialize a set of features (as a NullFeatureExtractor) from a string."""
import capa.features.extractors.null as null
freeze = Freeze.model_validate_json(s)
if freeze.version != 2:
raise ValueError(f"unsupported freeze format version: {freeze.version}")
return null.NullFeatureExtractor(
base_address=freeze.base_address.to_capa(),
global_features=[f.feature.to_capa() for f in freeze.features.global_],
file_features=[(f.address.to_capa(), f.feature.to_capa()) for f in freeze.features.file],
functions={
f.address.to_capa(): null.FunctionFeatures(
features=[(fe.address.to_capa(), fe.feature.to_capa()) for fe in f.features],
basic_blocks={
bb.address.to_capa(): null.BasicBlockFeatures(
features=[(fe.address.to_capa(), fe.feature.to_capa()) for fe in bb.features],
instructions={
i.address.to_capa(): null.InstructionFeatures(
features=[(fe.address.to_capa(), fe.feature.to_capa()) for fe in i.features]
)
for i in bb.instructions
},
)
for bb in f.basic_blocks
},
)
for f in freeze.features.functions
},
)
MAGIC = "capa0000".encode("ascii")
def dump(extractor: capa.features.extractors.base_extractor.FeatureExtractor) -> bytes:
"""serialize the given extractor to a byte array."""
return MAGIC + zlib.compress(dumps(extractor).encode("utf-8"))
def is_freeze(buf: bytes) -> bool:
return buf[: len(MAGIC)] == MAGIC
def load(buf: bytes) -> capa.features.extractors.base_extractor.FeatureExtractor:
"""deserialize a set of features (as a NullFeatureExtractor) from a byte array."""
if not is_freeze(buf):
raise ValueError("missing magic header")
return loads(zlib.decompress(buf[len(MAGIC) :]).decode("utf-8"))
def main(argv=None):
import sys
import argparse
from pathlib import Path
import capa.main
if argv is None:
argv = sys.argv[1:]
parser = argparse.ArgumentParser(description="save capa features to a file")
capa.main.install_common_args(parser, {"sample", "format", "backend", "os", "signatures"})
parser.add_argument("output", type=str, help="Path to output file")
args = parser.parse_args(args=argv)
capa.main.handle_common_args(args)
sigpaths = capa.main.get_signatures(args.signatures)
extractor = capa.main.get_extractor(args.sample, args.format, args.os, args.backend, sigpaths, False)
Path(args.output).write_bytes(dump(extractor))
return 0
if __name__ == "__main__":
import sys
sys.exit(main())

View File

@@ -1,376 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import binascii
from typing import Union, Optional
from pydantic import Field, BaseModel, ConfigDict
import capa.features.file
import capa.features.insn
import capa.features.common
import capa.features.basicblock
class FeatureModel(BaseModel):
model_config = ConfigDict(frozen=True, populate_by_name=True)
def to_capa(self) -> capa.features.common.Feature:
if isinstance(self, OSFeature):
return capa.features.common.OS(self.os, description=self.description)
elif isinstance(self, ArchFeature):
return capa.features.common.Arch(self.arch, description=self.description)
elif isinstance(self, FormatFeature):
return capa.features.common.Format(self.format, description=self.description)
elif isinstance(self, MatchFeature):
return capa.features.common.MatchedRule(self.match, description=self.description)
elif isinstance(
self,
CharacteristicFeature,
):
return capa.features.common.Characteristic(self.characteristic, description=self.description)
elif isinstance(self, ExportFeature):
return capa.features.file.Export(self.export, description=self.description)
elif isinstance(self, ImportFeature):
return capa.features.file.Import(self.import_, description=self.description)
elif isinstance(self, SectionFeature):
return capa.features.file.Section(self.section, description=self.description)
elif isinstance(self, FunctionNameFeature):
return capa.features.file.FunctionName(self.function_name, description=self.description)
elif isinstance(self, SubstringFeature):
return capa.features.common.Substring(self.substring, description=self.description)
elif isinstance(self, RegexFeature):
return capa.features.common.Regex(self.regex, description=self.description)
elif isinstance(self, StringFeature):
return capa.features.common.String(self.string, description=self.description)
elif isinstance(self, ClassFeature):
return capa.features.common.Class(self.class_, description=self.description)
elif isinstance(self, NamespaceFeature):
return capa.features.common.Namespace(self.namespace, description=self.description)
elif isinstance(self, BasicBlockFeature):
return capa.features.basicblock.BasicBlock(description=self.description)
elif isinstance(self, APIFeature):
return capa.features.insn.API(self.api, description=self.description)
elif isinstance(self, PropertyFeature):
return capa.features.insn.Property(self.property, access=self.access, description=self.description)
elif isinstance(self, NumberFeature):
return capa.features.insn.Number(self.number, description=self.description)
elif isinstance(self, BytesFeature):
return capa.features.common.Bytes(binascii.unhexlify(self.bytes), description=self.description)
elif isinstance(self, OffsetFeature):
return capa.features.insn.Offset(self.offset, description=self.description)
elif isinstance(self, MnemonicFeature):
return capa.features.insn.Mnemonic(self.mnemonic, description=self.description)
elif isinstance(self, OperandNumberFeature):
return capa.features.insn.OperandNumber(
self.index,
self.operand_number,
description=self.description,
)
elif isinstance(self, OperandOffsetFeature):
return capa.features.insn.OperandOffset(
self.index,
self.operand_offset,
description=self.description,
)
else:
raise NotImplementedError(f"Feature.to_capa({type(self)}) not implemented")
def feature_from_capa(f: capa.features.common.Feature) -> "Feature":
if isinstance(f, capa.features.common.OS):
assert isinstance(f.value, str)
return OSFeature(os=f.value, description=f.description)
elif isinstance(f, capa.features.common.Arch):
assert isinstance(f.value, str)
return ArchFeature(arch=f.value, description=f.description)
elif isinstance(f, capa.features.common.Format):
assert isinstance(f.value, str)
return FormatFeature(format=f.value, description=f.description)
elif isinstance(f, capa.features.common.MatchedRule):
assert isinstance(f.value, str)
return MatchFeature(match=f.value, description=f.description)
elif isinstance(f, capa.features.common.Characteristic):
assert isinstance(f.value, str)
return CharacteristicFeature(characteristic=f.value, description=f.description)
elif isinstance(f, capa.features.file.Export):
assert isinstance(f.value, str)
return ExportFeature(export=f.value, description=f.description)
elif isinstance(f, capa.features.file.Import):
assert isinstance(f.value, str)
return ImportFeature(import_=f.value, description=f.description) # type: ignore
# Mypy is unable to recognise `import_` as a argument due to alias
elif isinstance(f, capa.features.file.Section):
assert isinstance(f.value, str)
return SectionFeature(section=f.value, description=f.description)
elif isinstance(f, capa.features.file.FunctionName):
assert isinstance(f.value, str)
return FunctionNameFeature(function_name=f.value, description=f.description) # type: ignore
# Mypy is unable to recognise `function_name` as a argument due to alias
# must come before check for String due to inheritance
elif isinstance(f, capa.features.common.Substring):
assert isinstance(f.value, str)
return SubstringFeature(substring=f.value, description=f.description)
# must come before check for String due to inheritance
elif isinstance(f, capa.features.common.Regex):
assert isinstance(f.value, str)
return RegexFeature(regex=f.value, description=f.description)
elif isinstance(f, capa.features.common.String):
assert isinstance(f.value, str)
return StringFeature(string=f.value, description=f.description)
elif isinstance(f, capa.features.common.Class):
assert isinstance(f.value, str)
return ClassFeature(class_=f.value, description=f.description) # type: ignore
# Mypy is unable to recognise `class_` as a argument due to alias
elif isinstance(f, capa.features.common.Namespace):
assert isinstance(f.value, str)
return NamespaceFeature(namespace=f.value, description=f.description)
elif isinstance(f, capa.features.basicblock.BasicBlock):
return BasicBlockFeature(description=f.description)
elif isinstance(f, capa.features.insn.API):
assert isinstance(f.value, str)
return APIFeature(api=f.value, description=f.description)
elif isinstance(f, capa.features.insn.Property):
assert isinstance(f.value, str)
return PropertyFeature(property=f.value, access=f.access, description=f.description)
elif isinstance(f, capa.features.insn.Number):
assert isinstance(f.value, (int, float))
return NumberFeature(number=f.value, description=f.description)
elif isinstance(f, capa.features.common.Bytes):
buf = f.value
assert isinstance(buf, bytes)
return BytesFeature(bytes=binascii.hexlify(buf).decode("ascii"), description=f.description)
elif isinstance(f, capa.features.insn.Offset):
assert isinstance(f.value, int)
return OffsetFeature(offset=f.value, description=f.description)
elif isinstance(f, capa.features.insn.Mnemonic):
assert isinstance(f.value, str)
return MnemonicFeature(mnemonic=f.value, description=f.description)
elif isinstance(f, capa.features.insn.OperandNumber):
assert isinstance(f.value, int)
return OperandNumberFeature(index=f.index, operand_number=f.value, description=f.description) # type: ignore
# Mypy is unable to recognise `operand_number` as a argument due to alias
elif isinstance(f, capa.features.insn.OperandOffset):
assert isinstance(f.value, int)
return OperandOffsetFeature(index=f.index, operand_offset=f.value, description=f.description) # type: ignore
# Mypy is unable to recognise `operand_offset` as a argument due to alias
else:
raise NotImplementedError(f"feature_from_capa({type(f)}) not implemented")
class OSFeature(FeatureModel):
type: str = "os"
os: str
description: Optional[str] = None
class ArchFeature(FeatureModel):
type: str = "arch"
arch: str
description: Optional[str] = None
class FormatFeature(FeatureModel):
type: str = "format"
format: str
description: Optional[str] = None
class MatchFeature(FeatureModel):
type: str = "match"
match: str
description: Optional[str] = None
class CharacteristicFeature(FeatureModel):
type: str = "characteristic"
characteristic: str
description: Optional[str] = None
class ExportFeature(FeatureModel):
type: str = "export"
export: str
description: Optional[str] = None
class ImportFeature(FeatureModel):
type: str = "import"
import_: str = Field(alias="import")
description: Optional[str] = None
class SectionFeature(FeatureModel):
type: str = "section"
section: str
description: Optional[str] = None
class FunctionNameFeature(FeatureModel):
type: str = "function name"
function_name: str = Field(alias="function name")
description: Optional[str] = None
class SubstringFeature(FeatureModel):
type: str = "substring"
substring: str
description: Optional[str] = None
class RegexFeature(FeatureModel):
type: str = "regex"
regex: str
description: Optional[str] = None
class StringFeature(FeatureModel):
type: str = "string"
string: str
description: Optional[str] = None
class ClassFeature(FeatureModel):
type: str = "class"
class_: str = Field(alias="class")
description: Optional[str] = None
class NamespaceFeature(FeatureModel):
type: str = "namespace"
namespace: str
description: Optional[str] = None
class BasicBlockFeature(FeatureModel):
type: str = "basic block"
description: Optional[str] = None
class APIFeature(FeatureModel):
type: str = "api"
api: str
description: Optional[str] = None
class PropertyFeature(FeatureModel):
type: str = "property"
access: Optional[str] = None
property: str
description: Optional[str] = None
class NumberFeature(FeatureModel):
type: str = "number"
number: Union[int, float]
description: Optional[str] = None
class BytesFeature(FeatureModel):
type: str = "bytes"
bytes: str
description: Optional[str] = None
class OffsetFeature(FeatureModel):
type: str = "offset"
offset: int
description: Optional[str] = None
class MnemonicFeature(FeatureModel):
type: str = "mnemonic"
mnemonic: str
description: Optional[str] = None
class OperandNumberFeature(FeatureModel):
type: str = "operand number"
index: int
operand_number: int = Field(alias="operand number")
description: Optional[str] = None
class OperandOffsetFeature(FeatureModel):
type: str = "operand offset"
index: int
operand_offset: int = Field(alias="operand offset")
description: Optional[str] = None
Feature = Union[
OSFeature,
ArchFeature,
FormatFeature,
MatchFeature,
CharacteristicFeature,
ExportFeature,
ImportFeature,
SectionFeature,
FunctionNameFeature,
SubstringFeature,
RegexFeature,
StringFeature,
ClassFeature,
NamespaceFeature,
APIFeature,
PropertyFeature,
NumberFeature,
BytesFeature,
OffsetFeature,
MnemonicFeature,
OperandNumberFeature,
OperandOffsetFeature,
# Note! this must be last, see #1161
BasicBlockFeature,
]

View File

@@ -1,169 +1,40 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import abc
from typing import Union, Optional
import capa.helpers
from capa.features.common import VALID_FEATURE_ACCESS, Feature
def hex(n: int) -> str:
"""render the given number using upper case hex, like: 0x123ABC"""
if n < 0:
return f"-0x{(-n):X}"
else:
return f"0x{(n):X}"
from capa.features import Feature
class API(Feature):
def __init__(self, name: str, description=None):
super().__init__(name, description=description)
def __init__(self, name, description=None):
# Downcase library name if given
if "." in name:
modname, _, impname = name.rpartition(".")
name = modname.lower() + "." + impname
class _AccessFeature(Feature, abc.ABC):
# superclass: don't use directly
def __init__(self, value: str, access: Optional[str] = None, description: Optional[str] = None):
super().__init__(value, description=description)
if access is not None:
if access not in VALID_FEATURE_ACCESS:
raise ValueError(f"{self.name} access type {access} not valid")
self.access = access
def __hash__(self):
return hash((self.name, self.value, self.access))
def __eq__(self, other):
return super().__eq__(other) and self.access == other.access
def get_name_str(self) -> str:
if self.access is not None:
return f"{self.name}/{self.access}"
return self.name
class Property(_AccessFeature):
def __init__(self, value: str, access: Optional[str] = None, description=None):
super().__init__(value, access=access, description=description)
super(API, self).__init__(name, description=description)
class Number(Feature):
def __init__(self, value: Union[int, float], description=None):
"""
args:
value (int or float): positive or negative integer, or floating point number.
the range of the value is:
- if positive, the range of u64
- if negative, the range of i64
- if floating, the range and precision of double
"""
super().__init__(value, description=description)
def __init__(self, value, arch=None, description=None):
super(Number, self).__init__(value, arch=arch, description=description)
def get_value_str(self):
if isinstance(self.value, int):
return capa.helpers.hex(self.value)
elif isinstance(self.value, float):
return str(self.value)
else:
raise ValueError(f"invalid value type {type(self.value)}")
# max recognized structure size (and therefore, offset size)
MAX_STRUCTURE_SIZE = 0x10000
return "0x%X" % self.value
class Offset(Feature):
def __init__(self, value: int, description=None):
"""
args:
value (int): the offset, which can be positive or negative.
the range of the value is:
- if positive, the range of u64
- if negative, the range of i64
"""
super().__init__(value, description=description)
def __init__(self, value, arch=None, description=None):
super(Offset, self).__init__(value, arch=arch, description=description)
def get_value_str(self):
assert isinstance(self.value, int)
return hex(self.value)
return "0x%X" % self.value
class Mnemonic(Feature):
def __init__(self, value: str, description=None):
super().__init__(value, description=description)
# max number of operands to consider for a given instruction.
# since we only support Intel and .NET, we can assume this is 3
# which covers cases up to e.g. "vinserti128 ymm0,ymm0,ymm5,1"
MAX_OPERAND_COUNT = 4
MAX_OPERAND_INDEX = MAX_OPERAND_COUNT - 1
class _Operand(Feature, abc.ABC):
# superclass: don't use directly
# subclasses should set self.name and provide the value string formatter
def __init__(self, index: int, value: Union[int, float], description=None):
super().__init__(value, description=description)
self.index = index
def __hash__(self):
return hash((self.name, self.value))
def __eq__(self, other):
return super().__eq__(other) and self.index == other.index
class OperandNumber(_Operand):
# cached names so we don't do extra string formatting every ctor
NAMES = [f"operand[{i}].number" for i in range(MAX_OPERAND_COUNT)]
# operand[i].number: 0x12
def __init__(self, index: int, value: Union[int, float], description=None):
"""
args:
value (int or float): positive or negative integer, or floating point number.
the range of the value is:
- if positive, the range of u64
- if negative, the range of i64
- if floating, the range and precision of double
"""
super().__init__(index, value, description=description)
self.name = self.NAMES[index]
def get_value_str(self) -> str:
if isinstance(self.value, int):
return capa.helpers.hex(self.value)
elif isinstance(self.value, float):
return str(self.value)
else:
raise ValueError("invalid value type")
class OperandOffset(_Operand):
# cached names so we don't do extra string formatting every ctor
NAMES = [f"operand[{i}].offset" for i in range(MAX_OPERAND_COUNT)]
# operand[i].offset: 0x12
def __init__(self, index: int, value: int, description=None):
"""
args:
value (int): the offset, which can be positive or negative.
the range of the value is:
- if positive, the range of u64
- if negative, the range of i64
"""
super().__init__(index, value, description=description)
self.name = self.NAMES[index]
def get_value_str(self) -> str:
assert isinstance(self.value, int)
return hex(self.value)
def __init__(self, value, description=None):
super(Mnemonic, self).__init__(value, description=description)

View File

@@ -1,172 +0,0 @@
<div align="center">
<img src="/doc/img/ghidra_backend_logo.png" width=300 height=175>
</div>
The Ghidra feature extractor is an application of the FLARE team's open-source project, Ghidrathon, to integrate capa with Ghidra using Python 3. capa is a framework that uses a well-defined collection of rules to identify capabilities in a program. You can run capa against a PE file, ELF file, or shellcode and it tells you what it thinks the program can do. For example, it might suggest that the program is a backdoor, can install services, or relies on HTTP to communicate. The Ghidra feature extractor can be used to run capa analysis on your Ghidra databases without needing access to the original binary file.
<img src="/doc/img/ghidra_script_mngr_output.png">
## Getting Started
### Installation
Please ensure that you have the following dependencies installed before continuing:
| Dependency | Version | Source |
|------------|---------|--------|
| Ghidrathon | `>= 3.0.0` | https://github.com/mandiant/Ghidrathon |
| Python | `>= 3.8` | https://www.python.org/downloads |
| Ghidra | `>= 10.2` | https://ghidra-sre.org |
In order to run capa using using Ghidra, you must install capa as a library, obtain the official capa rules that match the capa version you have installed, and configure the Python 3 script [capa_ghidra.py](/capa/ghidra/capa_ghidra.py). You can do this by completing the following steps using the Python 3 interpreter that you have configured for your Ghidrathon installation:
1. Install capa and its dependencies from PyPI using the following command:
```bash
$ pip install flare-capa
```
2. Download and extract the [official capa rules](https://github.com/mandiant/capa-rules/releases) that match the capa version you have installed. Use the following command to view the version of capa you have installed:
```bash
$ pip show flare-capa
OR
$ capa --version
```
3. Copy [capa_ghidra.py](/capa/ghidra/capa_ghidra.py) to your `$USER_HOME/ghidra_scripts` directory or manually add `</path/to/ghidra_capa.py/>` to the Ghidra Script Manager.
## Usage
After completing the installation steps you can execute `capa_ghidra.py` using the Ghidra Script Manager or Headless Analyzer.
### Ghidra Script Manager
To execute `capa_ghidra.py` using the Ghidra Script Manager, first open the Ghidra Script Manager by navigating to `Window > Script Manager` in the Ghidra Code Browser. Next, locate `capa_ghidra.py` by selecting the `Python 3 > capa` category or using the Ghidra Script Manager search funtionality. Finally, double-click `capa_ghidra.py` to execute the script. If you don't see `capa_ghidra.py`, make sure you have copied the script to your `$USER_HOME/ghidra_scripts` directory or manually added `</path/to/ghidra_capa.py/>` to the Ghidra Script Manager
When executed, `capa_ghidra.py` asks you to provide your capa rules directory and preferred output format. `capa_ghidra.py` supports `default`, `verbose`, and `vverbose` output formats when executed from the Ghidra Script Manager. `capa_ghidra.py` writes output to the Ghidra Console Window.
#### Example
The following is an example of running `capa_ghidra.py` using the Ghidra Script Manager:
Selecting capa rules:
<img src="/doc/img/ghidra_script_mngr_rules.png">
Choosing output format:
<img src="/doc/img/ghidra_script_mngr_verbosity.png">
Viewing results in Ghidra Console Window:
<img src="/doc/img/ghidra_script_mngr_output.png">
### Ghidra Headless Analyzer
To execute `capa_ghidra.py` using the Ghidra Headless Analyzer, you can use the Ghidra `analyzeHeadless` script located in your `$GHIDRA_HOME/support` directory. You will need to provide the following arguments to the Ghidra `analyzeHeadless` script:
1. `</path/to/ghidra/project/>`: path to Ghidra project
2. `<ghidra_project_name>`: name of Ghidra Project
3. `-process <sample_name>`: name of sample `<sample_name>`
4. `-ScriptPath </path/to/capa_ghidra/>`: OPTIONAL argument specifying path `</path/to/capa_ghidra/>` to `capa_ghidra.py`
5. `-PostScript capa_ghidra.py`: executes `capa_ghidra.py` as post-analysis script
6. `"<capa_args>"`: single, quoted string containing capa arguments that must specify capa rules directory and output format, e.g. `"<path/to/capa/rules> --verbose"`. `capa_ghidra.py` supports `default`, `verbose`, `vverbose` and `json` formats when executed using the Ghidra Headless Analyzer. `capa_ghidra.py` writes output to the console window used to execute the Ghidra `analyzeHeadless` script.
7. `-processor <languageID>`: required ONLY if sample `<sample_name>` is shellcode. More information on specifying the `<languageID>` can be found in the `$GHIDRA_HOME/support/analyzeHeadlessREADME.html` documentation.
The following is an example of combining these arguments into a single `analyzeHeadless` script command:
```
$GHIDRA_HOME/support/analyzeHeadless </path/to/ghidra/project/> <ghidra_project_name> -process <sample_name> -PostScript capa_ghidra.py "/path/to/capa/rules/ --verbose"
```
You may also want to run capa against a sample that you have not yet imported into your Ghidra project. The following is an example of importing a sample and running `capa_ghidra.py` using a single `analyzeHeadless` script command:
```
$GHIDRA_HOME/support/analyzeHeadless </path/to/ghidra/project/> <ghidra_project_name> -Import </path/to/sample> -PostScript capa_ghidra.py "/path/to/capa/rules/ --verbose"
```
You can also provide `capa_ghidra.py` the single argument `"help"` to view supported arguments when running the script using the Ghidra Headless Analyzer:
```
$GHIDRA_HOME/support/analyzeHeadless </path/to/ghidra/project/> <ghidra_project_name> -process <sample_name> -PostScript capa_ghidra.py "help"
```
#### Example
The following is an example of running `capa_ghidra.py` against a shellcode sample using the Ghidra `analyzeHeadless` script:
```
$ analyzeHeadless /home/wumbo/Desktop/ghidra_projects/ capa_test -process 499c2a85f6e8142c3f48d4251c9c7cd6.raw32 -processor x86:LE:32:default -PostScript capa_ghidra.py "/home/wumbo/capa/rules -vv"
[...]
INFO REPORT: Analysis succeeded for file: /499c2a85f6e8142c3f48d4251c9c7cd6.raw32 (HeadlessAnalyzer)
INFO SCRIPT: /home/wumbo/ghidra_scripts/capa_ghidra.py (HeadlessAnalyzer)
md5 499c2a85f6e8142c3f48d4251c9c7cd6
sha1
sha256 e8e02191c1b38c808d27a899ac164b3675eb5cadd3a8907b0ffa863714000e72
path /home/wumbo/capa/tests/data/499c2a85f6e8142c3f48d4251c9c7cd6.raw32
timestamp 2023-08-29 17:57:00.946588
capa version 6.1.0
os unknown os
format Raw Binary
arch x86
extractor ghidra
base address global
rules /home/wumbo/capa/rules
function count 42
library function count 0
total feature count 1970
contain loop (24 matches, only showing first match of library rule)
author moritz.raabe@mandiant.com
scope function
function @ 0x0
or:
characteristic: loop @ 0x0
characteristic: tight loop @ 0x278
contain obfuscated stackstrings
namespace anti-analysis/obfuscation/string/stackstring
author moritz.raabe@mandiant.com
scope basic block
att&ck Defense Evasion::Obfuscated Files or Information::Indicator Removal from Tools [T1027.005]
mbc Anti-Static Analysis::Executable Code Obfuscation::Argument Obfuscation [B0032.020], Anti-Static Analysis::Executable Code Obfuscation::Stack Strings [B0032.017]
basic block @ 0x0 in function 0x0
characteristic: stack string @ 0x0
encode data using XOR
namespace data-manipulation/encoding/xor
author moritz.raabe@mandiant.com
scope basic block
att&ck Defense Evasion::Obfuscated Files or Information [T1027]
mbc Defense Evasion::Obfuscated Files or Information::Encoding-Standard Algorithm [E1027.m02], Data::Encode Data::XOR [C0026.002]
basic block @ 0x8AF in function 0x8A1
and:
characteristic: tight loop @ 0x8AF
characteristic: nzxor @ 0x8C0
not: = filter for potential false positives
or:
or: = unsigned bitwise negation operation (~i)
number: 0xFFFFFFFF = bitwise negation for unsigned 32 bits
number: 0xFFFFFFFFFFFFFFFF = bitwise negation for unsigned 64 bits
or: = signed bitwise negation operation (~i)
number: 0xFFFFFFF = bitwise negation for signed 32 bits
number: 0xFFFFFFFFFFFFFFF = bitwise negation for signed 64 bits
or: = Magic constants used in the implementation of strings functions.
number: 0x7EFEFEFF = optimized string constant for 32 bits
number: 0x81010101 = -0x81010101 = 0x7EFEFEFF
number: 0x81010100 = 0x81010100 = ~0x7EFEFEFF
number: 0x7EFEFEFEFEFEFEFF = optimized string constant for 64 bits
number: 0x8101010101010101 = -0x8101010101010101 = 0x7EFEFEFEFEFEFEFF
number: 0x8101010101010100 = 0x8101010101010100 = ~0x7EFEFEFEFEFEFEFF
get OS information via KUSER_SHARED_DATA
namespace host-interaction/os/version
author @mr-tz
scope function
att&ck Discovery::System Information Discovery [T1082]
references https://www.geoffchappell.com/studies/windows/km/ntoskrnl/inc/api/ntexapi_x/kuser_shared_data/index.htm
function @ 0x1CA6
or:
number: 0x7FFE026C = NtMajorVersion @ 0x1D18
Script /home/wumbo/ghidra_scripts/capa_ghidra.py called exit with code 0
[...]
```

View File

@@ -1,166 +0,0 @@
# Run capa against loaded Ghidra database
# @author Mike Hunhoff (mehunhoff@google.com)
# @category Python 3.capa
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import sys
import logging
import pathlib
import argparse
import capa
import capa.main
import capa.rules
import capa.ghidra.helpers
import capa.render.default
import capa.features.extractors.ghidra.extractor
logger = logging.getLogger("capa_ghidra")
def run_headless():
parser = argparse.ArgumentParser(description="The FLARE team's open-source tool to integrate capa with Ghidra.")
parser.add_argument(
"rules",
type=str,
help="path to rule file or directory",
)
parser.add_argument(
"-v", "--verbose", action="store_true", help="enable verbose result document (no effect with --json)"
)
parser.add_argument(
"-vv", "--vverbose", action="store_true", help="enable very verbose result document (no effect with --json)"
)
parser.add_argument("-d", "--debug", action="store_true", help="enable debugging output on STDERR")
parser.add_argument("-q", "--quiet", action="store_true", help="disable all output but errors")
parser.add_argument("-j", "--json", action="store_true", help="emit JSON instead of text")
script_args = list(getScriptArgs()) # type: ignore [name-defined] # noqa: F821
if not script_args or len(script_args) > 1:
script_args = []
else:
script_args = script_args[0].split()
for idx, arg in enumerate(script_args):
if arg.lower() == "help":
script_args[idx] = "--help"
args = parser.parse_args(args=script_args)
if args.quiet:
logging.basicConfig(level=logging.WARNING)
logging.getLogger().setLevel(logging.WARNING)
elif args.debug:
logging.basicConfig(level=logging.DEBUG)
logging.getLogger().setLevel(logging.DEBUG)
else:
logging.basicConfig(level=logging.INFO)
logging.getLogger().setLevel(logging.INFO)
logger.debug("running in Ghidra headless mode")
rules_path = pathlib.Path(args.rules)
logger.debug("rule path: %s", rules_path)
rules = capa.main.get_rules([rules_path])
meta = capa.ghidra.helpers.collect_metadata([rules_path])
extractor = capa.features.extractors.ghidra.extractor.GhidraFeatureExtractor()
capabilities, counts = capa.main.find_capabilities(rules, extractor, False)
meta.analysis.feature_counts = counts["feature_counts"]
meta.analysis.library_functions = counts["library_functions"]
meta.analysis.layout = capa.main.compute_layout(rules, extractor, capabilities)
if capa.main.has_file_limitation(rules, capabilities, is_standalone=True):
logger.info("capa encountered warnings during analysis")
if args.json:
print(capa.render.json.render(meta, rules, capabilities)) # noqa: T201
elif args.vverbose:
print(capa.render.vverbose.render(meta, rules, capabilities)) # noqa: T201
elif args.verbose:
print(capa.render.verbose.render(meta, rules, capabilities)) # noqa: T201
else:
print(capa.render.default.render(meta, rules, capabilities)) # noqa: T201
return 0
def run_ui():
logging.basicConfig(level=logging.INFO)
logging.getLogger().setLevel(logging.INFO)
rules_dir: str = ""
try:
selected_dir = askDirectory("Choose capa rules directory", "Ok") # type: ignore [name-defined] # noqa: F821
if selected_dir:
rules_dir = selected_dir.getPath()
except RuntimeError:
# RuntimeError thrown when user selects "Cancel"
pass
if not rules_dir:
logger.info("You must choose a capa rules directory before running capa.")
return capa.main.E_MISSING_RULES
verbose = askChoice( # type: ignore [name-defined] # noqa: F821
"capa output verbosity", "Choose capa output verbosity", ["default", "verbose", "vverbose"], "default"
)
rules_path: pathlib.Path = pathlib.Path(rules_dir)
logger.info("running capa using rules from %s", str(rules_path))
rules = capa.main.get_rules([rules_path])
meta = capa.ghidra.helpers.collect_metadata([rules_path])
extractor = capa.features.extractors.ghidra.extractor.GhidraFeatureExtractor()
capabilities, counts = capa.main.find_capabilities(rules, extractor, True)
meta.analysis.feature_counts = counts["feature_counts"]
meta.analysis.library_functions = counts["library_functions"]
meta.analysis.layout = capa.main.compute_layout(rules, extractor, capabilities)
if capa.main.has_file_limitation(rules, capabilities, is_standalone=False):
logger.info("capa encountered warnings during analysis")
if verbose == "vverbose":
print(capa.render.vverbose.render(meta, rules, capabilities)) # noqa: T201
elif verbose == "verbose":
print(capa.render.verbose.render(meta, rules, capabilities)) # noqa: T201
else:
print(capa.render.default.render(meta, rules, capabilities)) # noqa: T201
return 0
def main():
if not capa.ghidra.helpers.is_supported_ghidra_version():
return capa.main.E_UNSUPPORTED_GHIDRA_VERSION
if not capa.ghidra.helpers.is_supported_file_type():
return capa.main.E_INVALID_FILE_TYPE
if not capa.ghidra.helpers.is_supported_arch_type():
return capa.main.E_INVALID_FILE_ARCH
if isRunningHeadless(): # type: ignore [name-defined] # noqa: F821
return run_headless()
else:
return run_ui()
if __name__ == "__main__":
if sys.version_info < (3, 8):
from capa.exceptions import UnsupportedRuntimeError
raise UnsupportedRuntimeError("This version of capa can only be used with Python 3.8+")
sys.exit(main())

View File

@@ -1,159 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import logging
import datetime
import contextlib
from typing import List
from pathlib import Path
import capa
import capa.version
import capa.features.common
import capa.features.freeze
import capa.render.result_document as rdoc
import capa.features.extractors.ghidra.helpers
logger = logging.getLogger("capa")
# file type as returned by Ghidra
SUPPORTED_FILE_TYPES = ("Executable and Linking Format (ELF)", "Portable Executable (PE)", "Raw Binary")
class GHIDRAIO:
"""
An object that acts as a file-like object,
using bytes from the current Ghidra listing.
"""
def __init__(self):
super().__init__()
self.offset = 0
self.bytes_ = self.get_bytes()
def seek(self, offset, whence=0):
assert whence == 0
self.offset = offset
def read(self, size):
logger.debug("reading 0x%x bytes at 0x%x (ea: 0x%x)", size, self.offset, currentProgram().getImageBase().add(self.offset).getOffset()) # type: ignore [name-defined] # noqa: F821
if size > len(self.bytes_) - self.offset:
logger.debug("cannot read 0x%x bytes at 0x%x (ea: BADADDR)", size, self.offset)
return b""
else:
return self.bytes_[self.offset : self.offset + size]
def close(self):
return
def get_bytes(self):
file_bytes = currentProgram().getMemory().getAllFileBytes()[0] # type: ignore [name-defined] # noqa: F821
# getOriginalByte() allows for raw file parsing on the Ghidra side
# other functions will fail as Ghidra will think that it's reading uninitialized memory
bytes_ = [file_bytes.getOriginalByte(i) for i in range(file_bytes.getSize())]
return capa.features.extractors.ghidra.helpers.ints_to_bytes(bytes_)
def is_supported_ghidra_version():
version = float(getGhidraVersion()[:4]) # type: ignore [name-defined] # noqa: F821
if version < 10.2:
warning_msg = "capa does not support this Ghidra version"
logger.warning(warning_msg)
logger.warning("Your Ghidra version is: %s. Supported versions are: Ghidra >= 10.2", version)
return False
return True
def is_running_headless():
return isRunningHeadless() # type: ignore [name-defined] # noqa: F821
def is_supported_file_type():
file_info = currentProgram().getExecutableFormat() # type: ignore [name-defined] # noqa: F821
if file_info not in SUPPORTED_FILE_TYPES:
logger.error("-" * 80)
logger.error(" Input file does not appear to be a supported file type.")
logger.error(" ")
logger.error(
" capa currently only supports analyzing PE, ELF, or binary files containing x86 (32- and 64-bit) shellcode."
)
logger.error(" If you don't know the input file type, you can try using the `file` utility to guess it.")
logger.error("-" * 80)
return False
return True
def is_supported_arch_type():
lang_id = str(currentProgram().getLanguageID()).lower() # type: ignore [name-defined] # noqa: F821
if not all((lang_id.startswith("x86"), any(arch in lang_id for arch in ("32", "64")))):
logger.error("-" * 80)
logger.error(" Input file does not appear to target a supported architecture.")
logger.error(" ")
logger.error(" capa currently only supports analyzing x86 (32- and 64-bit).")
logger.error("-" * 80)
return False
return True
def get_file_md5():
return currentProgram().getExecutableMD5() # type: ignore [name-defined] # noqa: F821
def get_file_sha256():
return currentProgram().getExecutableSHA256() # type: ignore [name-defined] # noqa: F821
def collect_metadata(rules: List[Path]):
md5 = get_file_md5()
sha256 = get_file_sha256()
info = currentProgram().getLanguageID().toString() # type: ignore [name-defined] # noqa: F821
if "x86" in info and "64" in info:
arch = "x86_64"
elif "x86" in info and "32" in info:
arch = "x86"
else:
arch = "unknown arch"
format_name: str = currentProgram().getExecutableFormat() # type: ignore [name-defined] # noqa: F821
if "PE" in format_name:
os = "windows"
elif "ELF" in format_name:
with contextlib.closing(capa.ghidra.helpers.GHIDRAIO()) as f:
os = capa.features.extractors.elf.detect_elf_os(f)
else:
os = "unknown os"
return rdoc.Metadata(
timestamp=datetime.datetime.now(),
version=capa.version.__version__,
argv=(),
sample=rdoc.Sample(
md5=md5,
sha1="",
sha256=sha256,
path=currentProgram().getExecutablePath(), # type: ignore [name-defined] # noqa: F821
),
analysis=rdoc.Analysis(
format=currentProgram().getExecutableFormat(), # type: ignore [name-defined] # noqa: F821
arch=arch,
os=os,
extractor="ghidra",
rules=tuple(r.resolve().absolute().as_posix() for r in rules),
base_address=capa.features.freeze.Address.from_capa(currentProgram().getImageBase().getOffset()), # type: ignore [name-defined] # noqa: F821
layout=rdoc.Layout(
functions=(),
),
feature_counts=rdoc.FeatureCounts(file=0, functions=()),
library_functions=(),
),
)

View File

@@ -1,167 +1,36 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import inspect
import logging
import contextlib
import importlib.util
from typing import NoReturn
from pathlib import Path
import tqdm
import os
from capa.exceptions import UnsupportedFormatError
from capa.features.common import FORMAT_PE, FORMAT_SC32, FORMAT_SC64, FORMAT_DOTNET, FORMAT_UNKNOWN, Format
EXTENSIONS_SHELLCODE_32 = ("sc32", "raw32")
EXTENSIONS_SHELLCODE_64 = ("sc64", "raw64")
EXTENSIONS_ELF = "elf_"
logger = logging.getLogger("capa")
_hex = hex
def hex(n: int) -> str:
"""render the given number using upper case hex, like: 0x123ABC"""
if n < 0:
return f"-0x{(-n):X}"
else:
return f"0x{(n):X}"
def hex(i):
# under py2.7, long integers get formatted with a trailing `L`
# and this is not pretty. so strip it out.
return _hex(oint(i)).rstrip("L")
def get_file_taste(sample_path: Path) -> bytes:
if not sample_path.exists():
raise IOError(f"sample path {sample_path} does not exist or cannot be accessed")
taste = sample_path.open("rb").read(8)
def oint(i):
# there seems to be some trouble with using `int(viv_utils.Function)`
# with the black magic we do with binding the `__int__()` routine.
# i haven't had a chance to debug this yet (and i have no hotel wifi).
# so in the meantime, detect this, and call the method directly.
try:
return int(i)
except TypeError:
return i.__int__()
def get_file_taste(sample_path):
if not os.path.exists(sample_path):
raise IOError("sample path %s does not exist or cannot be accessed" % sample_path)
with open(sample_path, "rb") as f:
taste = f.read(8)
return taste
def is_runtime_ida():
return importlib.util.find_spec("idc") is not None
def is_runtime_ghidra():
try:
currentProgram # type: ignore [name-defined] # noqa: F821
except NameError:
return False
return True
def assert_never(value) -> NoReturn:
# careful: python -O will remove this assertion.
# but this is only used for type checking, so it's ok.
assert False, f"Unhandled value: {value} ({type(value).__name__})" # noqa: B011
def get_format_from_extension(sample: Path) -> str:
if sample.name.endswith(EXTENSIONS_SHELLCODE_32):
return FORMAT_SC32
elif sample.name.endswith(EXTENSIONS_SHELLCODE_64):
return FORMAT_SC64
return FORMAT_UNKNOWN
def get_auto_format(path: Path) -> str:
format_ = get_format(path)
if format_ == FORMAT_UNKNOWN:
format_ = get_format_from_extension(path)
if format_ == FORMAT_UNKNOWN:
raise UnsupportedFormatError()
return format_
def get_format(sample: Path) -> str:
# imported locally to avoid import cycle
from capa.features.extractors.common import extract_format
from capa.features.extractors.dnfile_ import DnfileFeatureExtractor
buf = sample.read_bytes()
for feature, _ in extract_format(buf):
if feature == Format(FORMAT_PE):
dnfile_extractor = DnfileFeatureExtractor(sample)
if dnfile_extractor.is_dotnet_file():
feature = Format(FORMAT_DOTNET)
assert isinstance(feature.value, str)
return feature.value
return FORMAT_UNKNOWN
@contextlib.contextmanager
def redirecting_print_to_tqdm(disable_progress):
"""
tqdm (progress bar) expects to have fairly tight control over console output.
so calls to `print()` will break the progress bar and make things look bad.
so, this context manager temporarily replaces the `print` implementation
with one that is compatible with tqdm.
via: https://stackoverflow.com/a/42424890/87207
"""
old_print = print # noqa: T202 [reserved word print used]
def new_print(*args, **kwargs):
# If tqdm.tqdm.write raises error, use builtin print
if disable_progress:
old_print(*args, **kwargs)
else:
try:
tqdm.tqdm.write(*args, **kwargs)
except Exception:
old_print(*args, **kwargs)
try:
# Globally replace print with new_print.
# Verified this works manually on Python 3.11:
# >>> import inspect
# >>> inspect.builtins
# <module 'builtins' (built-in)>
inspect.builtins.print = new_print # type: ignore
yield
finally:
inspect.builtins.print = old_print # type: ignore
def log_unsupported_format_error():
logger.error("-" * 80)
logger.error(" Input file does not appear to be a PE or ELF file.")
logger.error(" ")
logger.error(
" capa currently only supports analyzing PE and ELF files (or shellcode, when using --format sc32|sc64)."
)
logger.error(" If you don't know the input file type, you can try using the `file` utility to guess it.")
logger.error("-" * 80)
def log_unsupported_os_error():
logger.error("-" * 80)
logger.error(" Input file does not appear to target a supported OS.")
logger.error(" ")
logger.error(
" capa currently only supports analyzing executables for some operating systems (including Windows and Linux)."
)
logger.error("-" * 80)
def log_unsupported_arch_error():
logger.error("-" * 80)
logger.error(" Input file does not appear to target a supported architecture.")
logger.error(" ")
logger.error(" capa currently only supports analyzing x86 (32- and 64-bit).")
logger.error("-" * 80)
def log_unsupported_runtime_error():
logger.error("-" * 80)
logger.error(" Unsupported runtime or Python interpreter.")
logger.error(" ")
logger.error(" capa supports running under Python 3.8 and higher.")
logger.error(" ")
logger.error(
" If you're seeing this message on the command line, please ensure you're running a supported Python version."
)
logger.error("-" * 80)

View File

@@ -1,252 +0,0 @@
# Copyright (C) 2023 Mandiant, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import logging
import datetime
import contextlib
from typing import List, Optional
from pathlib import Path
import idc
import idaapi
import idautils
import ida_bytes
import ida_loader
from netnode import netnode
import capa
import capa.version
import capa.render.utils as rutils
import capa.features.common
import capa.features.freeze
import capa.render.result_document as rdoc
from capa.features.address import AbsoluteVirtualAddress
logger = logging.getLogger("capa")
# file type as returned by idainfo.file_type
SUPPORTED_FILE_TYPES = (
idaapi.f_PE,
idaapi.f_ELF,
idaapi.f_BIN,
idaapi.f_COFF,
# idaapi.f_MACHO,
)
# arch type as returned by idainfo.procname
SUPPORTED_ARCH_TYPES = ("metapc",)
CAPA_NETNODE = f"$ com.mandiant.capa.v{capa.version.__version__}"
NETNODE_RESULTS = "results"
NETNODE_RULES_CACHE_ID = "rules-cache-id"
def inform_user_ida_ui(message):
# this isn't a logger, this is IDA's logging facility
idaapi.info(f"{message}. Please refer to IDA Output window for more information.") # noqa: G004
def is_supported_ida_version():
version = float(idaapi.get_kernel_version())
if version < 7.4 or version >= 9:
warning_msg = "This plugin does not support your IDA Pro version"
logger.warning(warning_msg)
logger.warning("Your IDA Pro version is: %s. Supported versions are: IDA >= 7.4 and IDA < 9.0.", version)
return False
return True
def is_supported_file_type():
file_info = idaapi.get_inf_structure()
if file_info.filetype not in SUPPORTED_FILE_TYPES:
logger.error("-" * 80)
logger.error(" Input file does not appear to be a supported file type.")
logger.error(" ")
logger.error(
" capa currently only supports analyzing PE, ELF, or binary files containing x86 (32- and 64-bit) shellcode."
)
logger.error(" If you don't know the input file type, you can try using the `file` utility to guess it.")
logger.error("-" * 80)
return False
return True
def is_supported_arch_type():
file_info = idaapi.get_inf_structure()
if file_info.procname not in SUPPORTED_ARCH_TYPES or not any((file_info.is_32bit(), file_info.is_64bit())):
logger.error("-" * 80)
logger.error(" Input file does not appear to target a supported architecture.")
logger.error(" ")
logger.error(" capa currently only supports analyzing x86 (32- and 64-bit).")
logger.error("-" * 80)
return False
return True
def get_disasm_line(va):
""" """
return idc.generate_disasm_line(va, idc.GENDSM_FORCE_CODE)
def is_func_start(ea):
"""check if function stat exists at virtual address"""
f = idaapi.get_func(ea)
return f and f.start_ea == ea
def get_func_start_ea(ea):
""" """
f = idaapi.get_func(ea)
return f if f is None else f.start_ea
def get_file_md5():
""" """
md5 = idautils.GetInputFileMD5()
if not isinstance(md5, str):
md5 = capa.features.common.bytes_to_str(md5)
return md5
def get_file_sha256():
""" """
sha256 = idaapi.retrieve_input_file_sha256()
if not isinstance(sha256, str):
sha256 = capa.features.common.bytes_to_str(sha256)
return sha256
def collect_metadata(rules: List[Path]):
""" """
md5 = get_file_md5()
sha256 = get_file_sha256()
info: idaapi.idainfo = idaapi.get_inf_structure()
if info.procname == "metapc" and info.is_64bit():
arch = "x86_64"
elif info.procname == "metapc" and info.is_32bit():
arch = "x86"
else:
arch = "unknown arch"
format_name: str = ida_loader.get_file_type_name()
if "PE" in format_name:
os = "windows"
elif "ELF" in format_name:
with contextlib.closing(capa.ida.helpers.IDAIO()) as f:
os = capa.features.extractors.elf.detect_elf_os(f)
else:
os = "unknown os"
return rdoc.Metadata(
timestamp=datetime.datetime.now(),
version=capa.version.__version__,
argv=(),
sample=rdoc.Sample(
md5=md5,
sha1="", # not easily accessible
sha256=sha256,
path=idaapi.get_input_file_path(),
),
analysis=rdoc.Analysis(
format=idaapi.get_file_type_name(),
arch=arch,
os=os,
extractor="ida",
rules=tuple(r.resolve().absolute().as_posix() for r in rules),
base_address=capa.features.freeze.Address.from_capa(idaapi.get_imagebase()),
layout=rdoc.Layout(
functions=(),
# this is updated after capabilities have been collected.
# will look like:
#
# "functions": { 0x401000: { "matched_basic_blocks": [ 0x401000, 0x401005, ... ] }, ... }
),
# ignore these for now - not used by IDA plugin.
feature_counts=rdoc.FeatureCounts(file=0, functions=()),
library_functions=(),
),
)
class IDAIO:
"""
An object that acts as a file-like object,
using bytes from the current IDB workspace.
"""
def __init__(self):
super().__init__()
self.offset = 0
def seek(self, offset, whence=0):
assert whence == 0
self.offset = offset
def read(self, size):
ea = ida_loader.get_fileregion_ea(self.offset)
if ea == idc.BADADDR:
logger.debug("cannot read 0x%x bytes at 0x%x (ea: BADADDR)", size, self.offset)
return b""
logger.debug("reading 0x%x bytes at 0x%x (ea: 0x%x)", size, self.offset, ea)
# get_bytes returns None on error, for consistency with read always return bytes
return ida_bytes.get_bytes(ea, size) or b""
def close(self):
return
def save_cached_results(resdoc):
logger.debug("saving cached capa results to netnode '%s'", CAPA_NETNODE)
n = netnode.Netnode(CAPA_NETNODE)
n[NETNODE_RESULTS] = resdoc.json()
def idb_contains_cached_results() -> bool:
try:
n = netnode.Netnode(CAPA_NETNODE)
return bool(n.get(NETNODE_RESULTS))
except netnode.NetnodeCorruptError as e:
logger.exception(str(e))
return False
def load_and_verify_cached_results() -> Optional[rdoc.ResultDocument]:
"""verifies that cached results have valid (mapped) addresses for the current database"""
logger.debug("loading cached capa results from netnode '%s'", CAPA_NETNODE)
n = netnode.Netnode(CAPA_NETNODE)
doc = rdoc.ResultDocument.model_validate_json(n[NETNODE_RESULTS])
for rule in rutils.capability_rules(doc):
for location_, _ in rule.matches:
location = location_.to_capa()
if isinstance(location, AbsoluteVirtualAddress):
ea = int(location)
if not idaapi.is_mapped(ea):
logger.error("cached address %s is not a valid location in this database", hex(ea))
return None
return doc
def save_rules_cache_id(ruleset_id):
logger.debug("saving ruleset ID to netnode '%s'", CAPA_NETNODE)
n = netnode.Netnode(CAPA_NETNODE)
n[NETNODE_RULES_CACHE_ID] = ruleset_id
def load_rules_cache_id():
n = netnode.Netnode(CAPA_NETNODE)
return n[NETNODE_RULES_CACHE_ID]
def delete_cached_results():
logger.debug("deleting cached capa data")
n = netnode.Netnode(CAPA_NETNODE)
del n[NETNODE_RESULTS]

View File

@@ -0,0 +1,122 @@
# Copyright (C) 2020 FireEye, Inc. All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at: [package root]/LICENSE.txt
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.
import logging
import datetime
import idc
import six
import idaapi
import idautils
import capa
logger = logging.getLogger("capa")
SUPPORTED_IDA_VERSIONS = [
"7.1",
"7.2",
"7.3",
"7.4",
"7.5",
"7.6",
]
# file type names as returned by idaapi.get_file_type_name()
SUPPORTED_FILE_TYPES = [
"Portable executable for 80386 (PE)",
"Portable executable for AMD64 (PE)",
"Binary file", # x86/AMD64 shellcode support
]
def inform_user_ida_ui(message):
idaapi.info("%s. Please refer to IDA Output window for more information." % message)
def is_supported_ida_version():
version = idaapi.get_kernel_version()
if version not in SUPPORTED_IDA_VERSIONS:
warning_msg = "This plugin does not support your IDA Pro version"
logger.warning(warning_msg)
logger.warning(
"Your IDA Pro version is: %s. Supported versions are: %s." % (version, ", ".join(SUPPORTED_IDA_VERSIONS))
)
return False
return True
def is_supported_file_type():
file_type = idaapi.get_file_type_name()
if file_type not in SUPPORTED_FILE_TYPES:
logger.error("-" * 80)
logger.error(" Input file does not appear to be a PE file.")
logger.error(" ")
logger.error(
" capa currently only supports analyzing PE files (or binary files containing x86/AMD64 shellcode) with IDA."
)
logger.error(" If you don't know the input file type, you can try using the `file` utility to guess it.")
logger.error("-" * 80)
return False
return True
def get_disasm_line(va):
""" """
return idc.generate_disasm_line(va, idc.GENDSM_FORCE_CODE)
def is_func_start(ea):
""" check if function stat exists at virtual address """
f = idaapi.get_func(ea)
return f and f.start_ea == ea
def get_func_start_ea(ea):
""" """
f = idaapi.get_func(ea)
return f if f is None else f.start_ea
def get_file_md5():
""" """
md5 = idautils.GetInputFileMD5()
if not isinstance(md5, six.string_types):
md5 = capa.features.bytes_to_str(md5)
return md5
def get_file_sha256():
""" """
sha256 = idaapi.retrieve_input_file_sha256()
if not isinstance(sha256, six.string_types):
sha256 = capa.features.bytes_to_str(sha256)
return sha256
def collect_metadata():
""" """
md5 = get_file_md5()
sha256 = get_file_sha256()
return {
"timestamp": datetime.datetime.now().isoformat(),
# "argv" is not relevant here
"sample": {
"md5": md5,
"sha1": "", # not easily accessible
"sha256": sha256,
"path": idaapi.get_input_file_path(),
},
"analysis": {
"format": idaapi.get_file_type_name(),
"extractor": "ida",
"base_address": idaapi.get_imagebase(),
},
"version": capa.version.__version__,
}

Some files were not shown because too many files have changed in this diff Show More