capa/doc/installation.md

Installation

You can install capa in a few different ways. First, if you simply want to use capa, just download the standalone binary. If you want to use capa as a Python library, you can install the package directly from GitHub using pip. If you'd like to contribute patches or features to capa, you can work with a local copy of the source code.

Method 1: Standalone installation

If you simply want to use capa, use the standalone binaries we host on GitHub: https://github.com/fireeye/capa/releases. These binary executable files contain all the source code, Python interpreter, and associated resources needed to make capa run. This means you can run it without any installation! Just invoke the file using your terminal shell to see the help documentation.

We use PyInstaller to create these packages.

The capa README also links to nightly builds of standalone binaries from the latest development branch.

MacOS Standalone installation

By default, on MacOS Catalina or greater, Gatekeeper will block execution of the standalone binary. To resolve this, simply try to execute it once on the command-line and then go to System Preferences / Security & Privacy / General and approve the application:

Method 2: Using capa as a Python library

To install capa as a Python library, you'll need to install a few dependencies, and then use pip to fetch the capa module. Note: this technique doesn't pull the default rule set, so you should check it out separately from capa-rules and pass the directory to the entrypoint using -r.

1. Install requirements

First, install the requirements. $ pip install https://github.com/williballenthin/vivisect/zipball/master

2. Install capa module

Second, use pip to install the capa module to your local Python environment. This fetches the library code to your computer but does not keep editable source files around for you to hack on. If you'd like to edit the source files, see below. $ pip install https://github.com/fireeye/capa/archive/master.zip

3. Use capa

You can now import the capa module from a Python script or use the IDA Pro plugins from the capa/ida directory. For more information please see the usage documentation.

Method 3: Inspecting the capa source code

If you'd like to review and modify the capa source code, you'll need to check it out from GitHub and install it locally. By following these instructions, you'll maintain a local directory of source code that you can modify and run easily.

1. Install requirements

First, install the requirements. $ pip install https://github.com/williballenthin/vivisect/zipball/master

2. Check out source code

Next, clone the capa git repository. We use submodules to separate code, rules, and test data. See below to get all data at once. To only get the source code and our provided rules (common), follow these steps:

• clone repository
  • $ git clone https://github.com/fireeye/capa.git /local/path/to/src (HTTPS)
  • $ git clone git@github.com:fireeye/capa.git /local/path/to/src (SSH)
• $ cd /local/path/to/src
• $ git submodule init
• $ git submodule update rules

capa-testfiles

The capa-testfiles repository (/local/path/to/src/tests/data) contains a large collection of malware and benign test files. In most cases you will not need to check it out on your local system.

To update the testfiles you can use the following command:

• $ git submodule update tests/data

To get all data at once use the --recurse-submodules option:

• $ git clone --recurse-submodules https://github.com/fireeye/capa.git /local/path/to/src (HTTPS)
• $ git clone --recurse-submodules git@github.com:fireeye/capa.git /local/path/to/src (SSH)

3. Install the local source code

Finally, use pip to install the source code in "editable" mode. This means that Python will load the capa module from the local directory rather than copying it to site-packages or dist-packages. This is good because it is easy to modify files and see the effects reflected immediately. But, be careful not to remove this directory unless uninstalling capa.

$ pip install -e /local/path/to/src

You'll find that the capa.exe (Windows) or capa (Linux) executables in your path now invoke the capa binary from this directory.

We use the following tools to ensure consistent code style and formatting:

• black code formatter, with -l 120
• isort 5 code formatter, with --profile black --length-sort --line-width 120
• dos2unix for UNIX-style LF newlines
• capafmt rule formatter

To install these development dependencies, run:

$ pip install -e /local/path/to/src[dev]

Note that some development dependencies (including the black code formatter) require Python 3.

4. Setup hooks [optional]

If you plan to contribute to capa, you may want to setup the hooks. Run scripts/setup-hooks.sh to set the following hooks up:

• The post-commit hook runs checks after every git commit, letting you know if there are code style or rule linter offenses you need to fix.
• The pre-push hook runs various style and lint checks as well as the tests. If they do not succeed git push is blocked. This way you can ensure everything is alright before sending a pull request.