mirror of
https://github.com/Cisco-Talos/clamav.git
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70 lines
1.9 KiB
Python
70 lines
1.9 KiB
Python
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#!/usr/bin/env python3
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"""
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Decrypt (or encrypt) a file with a hardcoded xor key (below).
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This feature is to prevent other malware detection engines from alerting on our
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suspicious-looking-but-benign test files, such as the packed executables.
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The test files are xor'ed so our source and source tarball aren't quarantined.
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"""
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import argparse
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import os
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from pathlib import Path
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import sys
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xor_key = b'\
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bhcftqarohcdiayfohalohkgmoefxrrg\
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fnczssgybajvkzjaahpfrlqsratkhhfv\
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pxytculmwgmtyzujlbjlgrhtwxhzpjaz\
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libbwepffyjyfkjwzyofgpopoueurinp\
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dujkphxwhnaxfkaiwrpzdqsnwughtejr\
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'
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def main():
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parser = argparse.ArgumentParser()
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parser.add_argument("--in_file", help="Input file", required=True)
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parser.add_argument("--out_file", help="Output file (will over-write!)", required=True)
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args = parser.parse_args()
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in_file = Path(args.in_file)
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if not in_file.exists():
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print("Error: Input file to be XOR'd does not exist: {}".format(in_file))
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sys.exit(1)
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out_file = Path(args.out_file)
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if out_file.exists():
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print("Warning: Replacing existing file: {}".format(out_file))
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os.remove(str(out_file))
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in_file_bytes = in_file.read_bytes()
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out_file_bytes = bytearray()
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# XOR the source file with the XOR key
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i = 0
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while i < len(in_file_bytes):
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for j in range(0, len(xor_key)):
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if i + j == len(in_file_bytes):
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break
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out_file_bytes.append(in_file_bytes[i + j] ^ xor_key[j])
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i += len(xor_key)
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# Write out the result to the destination file.
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try:
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with out_file.open('w+b') as out_file_fd:
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out_file_fd.write(out_file_bytes)
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print("Created: '{}'".format(out_file))
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except Exception as exc:
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print("Failed to create file: {}. Exception: {}".format(out_file, exc))
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sys.exit(1)
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sys.exit(0)
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if __name__ == "__main__":
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main()
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