Files
capa/capa/helpers.py
2022-05-24 12:29:56 -06:00

119 lines
3.6 KiB
Python

# Copyright (C) 2020 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 os
import logging
from typing import NoReturn
from capa.exceptions import UnsupportedFormatError
from capa.features.common import FORMAT_SC32, FORMAT_SC64, FORMAT_UNKNOWN
EXTENSIONS_SHELLCODE_32 = ("sc32", "raw32")
EXTENSIONS_SHELLCODE_64 = ("sc64", "raw64")
logger = logging.getLogger("capa")
_hex = hex
def hex(i):
return _hex(int(i))
def get_file_taste(sample_path: str) -> bytes:
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():
try:
import idc
except ImportError:
return False
else:
return True
def assert_never(value: NoReturn) -> NoReturn:
assert False, f"Unhandled value: {value} ({type(value).__name__})"
def get_format_from_extension(sample: str) -> str:
if sample.endswith(EXTENSIONS_SHELLCODE_32):
return FORMAT_SC32
elif sample.endswith(EXTENSIONS_SHELLCODE_64):
return FORMAT_SC64
return FORMAT_UNKNOWN
def get_auto_format(path: str) -> 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: str) -> str:
# imported locally to avoid import cycle
from capa.features.extractors.common import extract_format
with open(sample, "rb") as f:
buf = f.read()
for feature, _ in extract_format(buf):
assert isinstance(feature.value, str)
return feature.value
return FORMAT_UNKNOWN
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 3.7 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)