mirror of
https://github.com/mandiant/capa.git
synced 2025-12-06 12:51:03 -08:00
3cd97ae9f2
Replace the header from source code files using the following script:
```Python
for dir_path, dir_names, file_names in os.walk("capa"):
for file_name in file_names:
# header are only in `.py` and `.toml` files
if file_name[-3:] not in (".py", "oml"):
continue
file_path = f"{dir_path}/{file_name}"
f = open(file_path, "rb+")
content = f.read()
m = re.search(OLD_HEADER, content)
if not m:
continue
print(f"{file_path}: {m.group('year')}")
content = content.replace(m.group(0), NEW_HEADER % m.group("year"))
f.seek(0)
f.write(content)
```
Some files had the copyright headers inside a `"""` comment and needed
manual changes before applying the script. `hook-vivisect.py` and
`pyinstaller.spec` didn't include the license in the header and also
needed manual changes.
The old header had the confusing sentence `All rights reserved`, which
does not make sense for an open source license. Replace the header by
the default Google header that corrects this issue and keep capa
consistent with other Google projects.
Adapt the linter to work with the new header.
Replace also the copyright text in the `web/public/index.html` file for
consistency.
321 lines
11 KiB
Python
321 lines
11 KiB
Python
#!/usr/bin/env python2
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# Copyright 2020 Google LLC
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""
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show-features
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Show the features that capa extracts from the given sample,
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to assist with the development of rules.
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If you have a function with a capability that you'd like to detect,
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you can run this tool and grep for the function/basic block/instruction addresses
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to see what capa picks up.
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This way, you can verify that capa successfully notices the features you'd reference.
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Example::
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$ python scripts/show-features.py /tmp/suspicious.dll_
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...
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file: 0x10004e4d: export(__entry)
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file: 0x10004706: export(Install)
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file: 0x10004c2b: export(uninstallA)
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file: 0x10005034: import(kernel32.GetStartupInfoA)
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file: 0x10005034: import(GetStartupInfoA)
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file: 0x10005048: import(kernel32.SetLastError)
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file: 0x00004e10: string(Y29ubmVjdA==)
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file: 0x00004e28: string(practicalmalwareanalysis.com)
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file: 0x00004e68: string(serve.html)
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file: 0x00004eb8: string(dW5zdXBwb3J0)
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file: 0x00004ec8: string(c2xlZXA=)
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func: 0x100012c2: characteristic(calls to)
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func: 0x10001000: characteristic(loop)
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bb : 0x10001000: basic block
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insn: 0x10001000: mnemonic(push)
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insn: 0x10001001: mnemonic(push)
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insn: 0x10001002: mnemonic(push)
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insn: 0x10001003: mnemonic(push)
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insn: 0x10001004: mnemonic(push)
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insn: 0x10001005: mnemonic(push)
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insn: 0x10001006: mnemonic(xor)
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insn: 0x10001008: number(0x1)
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insn: 0x10001008: mnemonic(mov)
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bb : 0x1000100a: basic block
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bb : 0x1000100a: characteristic(tight loop)
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insn: 0x1000100a: mnemonic(movzx)
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insn: 0x1000100d: mnemonic(mov)
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insn: 0x1000100f: offset(0x1000A7C8)
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insn: 0x1000100f: mnemonic(mov)
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insn: 0x10001015: offset(0x100075C8)
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insn: 0x10001015: mnemonic(mov)
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insn: 0x1000101b: mnemonic(mov)
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insn: 0x1000101d: number(0x80)
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insn: 0x1000101d: mnemonic(and)
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insn: 0x10001020: mnemonic(neg)
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insn: 0x10001022: mnemonic(sbb)
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insn: 0x10001024: number(0x1B)
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insn: 0x10001024: mnemonic(and)
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insn: 0x10001027: number(0x1)
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insn: 0x10001027: mnemonic(shl)
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...
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"""
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import sys
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import logging
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import argparse
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import capa.main
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import capa.rules
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import capa.engine
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import capa.loader
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import capa.helpers
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import capa.features
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import capa.exceptions
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import capa.render.verbose as v
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import capa.features.freeze
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import capa.features.address
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import capa.features.extractors.pefile
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from capa.helpers import assert_never
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from capa.features.insn import API, Number
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from capa.features.common import String, Feature, is_global_feature
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from capa.features.extractors.base_extractor import FunctionHandle, StaticFeatureExtractor, DynamicFeatureExtractor
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logger = logging.getLogger("capa.show-features")
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def format_address(addr: capa.features.address.Address) -> str:
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return v.format_address(capa.features.freeze.Address.from_capa((addr)))
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def main(argv=None):
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if argv is None:
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argv = sys.argv[1:]
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parser = argparse.ArgumentParser(description="Show the features that capa extracts from the given sample")
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capa.main.install_common_args(parser, wanted={"input_file", "format", "os", "signatures", "backend"})
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parser.add_argument("-F", "--function", type=str, help="Show features for specific function")
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parser.add_argument("-P", "--process", type=str, help="Show features for specific process name")
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args = parser.parse_args(args=argv)
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try:
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capa.main.handle_common_args(args)
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capa.main.ensure_input_exists_from_cli(args)
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if args.function and args.backend == "pefile":
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print("pefile backend does not support extracting function features")
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return -1
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input_format = capa.main.get_input_format_from_cli(args)
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backend = capa.main.get_backend_from_cli(args, input_format)
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extractor = capa.main.get_extractor_from_cli(args, input_format, backend)
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except capa.main.ShouldExitError as e:
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return e.status_code
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if isinstance(extractor, DynamicFeatureExtractor):
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print_dynamic_analysis(extractor, args)
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elif isinstance(extractor, StaticFeatureExtractor):
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print_static_analysis(extractor, args)
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else:
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assert_never(extractor)
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return 0
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def print_static_analysis(extractor: StaticFeatureExtractor, args):
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for feature, addr in extractor.extract_global_features():
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print(f"global: {format_address(addr)}: {feature}")
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if not args.function:
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for feature, addr in extractor.extract_file_features():
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print(f"file: {format_address(addr)}: {feature}")
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function_handles: tuple[FunctionHandle, ...]
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if isinstance(extractor, capa.features.extractors.pefile.PefileFeatureExtractor):
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# pefile extractor doesn't extract function features
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function_handles = ()
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else:
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function_handles = tuple(extractor.get_functions())
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if args.function:
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if args.format == "freeze":
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function_handles = tuple(filter(lambda fh: fh.address == args.function, function_handles))
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else:
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function_handles = tuple(filter(lambda fh: format_address(fh.address) == args.function, function_handles))
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if args.function not in [format_address(fh.address) for fh in function_handles]:
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print(f"{args.function} not a function")
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return -1
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if len(function_handles) == 0:
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print(f"{args.function} not a function")
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return -1
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print_static_features(function_handles, extractor)
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def print_dynamic_analysis(extractor: DynamicFeatureExtractor, args):
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for feature, addr in extractor.extract_global_features():
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print(f"global: {format_address(addr)}: {feature}")
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if not args.process:
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for feature, addr in extractor.extract_file_features():
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print(f"file: {format_address(addr)}: {feature}")
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process_handles = tuple(extractor.get_processes())
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if args.process:
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process_handles = tuple(filter(lambda ph: extractor.get_process_name(ph) == args.process, process_handles))
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if args.process not in [extractor.get_process_name(ph) for ph in process_handles]:
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print(f"{args.process} not a process")
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return -1
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print_dynamic_features(process_handles, extractor)
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def print_static_features(functions, extractor: StaticFeatureExtractor):
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for f in functions:
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if extractor.is_library_function(f.address):
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function_name = extractor.get_function_name(f.address)
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logger.debug("skipping library function %s (%s)", format_address(f.address), function_name)
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continue
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print(f"func: {format_address(f.address)}")
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for feature, addr in extractor.extract_function_features(f):
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if is_global_feature(feature):
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continue
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if f.address != addr:
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print(f" func: {format_address(f.address)}: {feature} -> {format_address(addr)}")
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else:
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print(f" func: {format_address(f.address)}: {feature}")
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for bb in extractor.get_basic_blocks(f):
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for feature, addr in extractor.extract_basic_block_features(f, bb):
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if is_global_feature(feature):
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continue
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if bb.address != addr:
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print(f" bb: {format_address(bb.address)}: {feature} -> {format_address(addr)}")
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else:
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print(f" bb: {format_address(bb.address)}: {feature}")
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for insn in extractor.get_instructions(f, bb):
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for feature, addr in extractor.extract_insn_features(f, bb, insn):
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if is_global_feature(feature):
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continue
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try:
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if insn.address != addr:
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print(
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f" insn: {format_address(f.address)}: {format_address(insn.address)}: {feature} -> {format_address(addr)}"
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)
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else:
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print(f" insn: {format_address(insn.address)}: {feature}")
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except UnicodeEncodeError:
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# may be an issue while piping to less and encountering non-ascii characters
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continue
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def print_dynamic_features(processes, extractor: DynamicFeatureExtractor):
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for p in processes:
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print(f"proc: {extractor.get_process_name(p)} (ppid={p.address.ppid}, pid={p.address.pid})")
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for feature, _ in extractor.extract_process_features(p):
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if is_global_feature(feature):
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continue
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print(f" proc: {extractor.get_process_name(p)}: {feature}")
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for t in extractor.get_threads(p):
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print(f" thread: {t.address.tid}")
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for feature, addr in extractor.extract_thread_features(p, t):
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if is_global_feature(feature):
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continue
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if feature != Feature(0):
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print(f" {format_address(addr)}: {feature}")
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for call in extractor.get_calls(p, t):
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apis = []
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arguments = []
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for feature, addr in extractor.extract_call_features(p, t, call):
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if is_global_feature(feature):
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continue
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if isinstance(feature, API):
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assert isinstance(addr, capa.features.address.DynamicCallAddress)
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apis.append((addr.id, str(feature.value)))
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if isinstance(feature, (Number, String)):
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arguments.append(str(feature.value))
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for cid, api in apis:
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print(f" call {cid}: {api}({', '.join(arguments)})")
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def ida_main():
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import idc
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import capa.features.extractors.ida.extractor
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function = idc.get_func_attr(idc.here(), idc.FUNCATTR_START)
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print(f"getting features for current function {hex(function)}")
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extractor = capa.features.extractors.ida.extractor.IdaFeatureExtractor()
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if not function:
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for feature, addr in extractor.extract_file_features():
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print(f"file: {format_address(addr)}: {feature}")
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return
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function_handles = tuple(extractor.get_functions())
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if function:
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function_handles = tuple(filter(lambda fh: fh.inner.start_ea == function, function_handles))
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if len(function_handles) == 0:
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print(f"{hex(function)} not a function")
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return -1
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print_static_features(function_handles, extractor)
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return 0
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def ghidra_main():
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import capa.features.extractors.ghidra.extractor
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extractor = capa.features.extractors.ghidra.extractor.GhidraFeatureExtractor()
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for feature, addr in extractor.extract_file_features():
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print(f"file: {format_address(addr)}: {feature}")
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function_handles = tuple(extractor.get_functions())
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print_static_features(function_handles, extractor)
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return 0
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if __name__ == "__main__":
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if capa.helpers.is_runtime_ida():
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ida_main()
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elif capa.helpers.is_runtime_ghidra():
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ghidra_main()
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else:
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sys.exit(main())
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