Python script to bruteforce gzip data

find-data.py

#!/usr/bin/env python3

#
# find-data.py
#
# A small script to bruteforce embedded compressed data that might not have a header
# Useful for raw binary firmware images that do not contain a standard
# binary header (ELF, PE, MACH-O).
#
# Usage: python find-data.py "filename.bin"
#
import zlib, sys, lzma, bz2, threading, copy

DECOMPRESSION_CHAMBER_PATH = "/tmp/decompression-chamber"
DIVISOR = 8

def do_bz2(compressed_data):
    data_length = len(compressed_data)
    for i in range(int(data_length)):
        try: 
            unzipped = bz2.decompress(compressed_data[i:])
        except Exception as ex:
            continue
        if len(unzipped) > int((data_length / DIVISOR)):
            print ('BZ2: Offset Found', i)
            with open(DECOMPRESSION_CHAMBER_PATH + '/result-bz2-' + str(i) + '.bin', 'wb') as result:
                result.write(unzipped);
                result.close()
                break
        

def do_lzma(compressed_data):
    data_length = len(compressed_data)
    for i in range(int(data_length)):
        try: 
            unzipped = lzma.decompress(compressed_data[i:])
        except Exception as ex:
            continue
        if len(unzipped) > int((data_length / DIVISOR)):
            print ('LZMA: Offset Found', i)
            with open(DECOMPRESSION_CHAMBER_PATH + '/result-lzma-' + str(i) + '.bin', 'wb') as result:
                result.write(unzipped);
                result.close()
                break
        
        
def do_zlib(compressed_data):
    data_length = len(compressed_data)
    for i in range(int(data_length)):
        try:
            unzipped = zlib.decompress(compressed_data[i:], -zlib.MAX_WBITS)
        except Exception as ex:
            continue

        if len(unzipped) > int((data_length / DIVISOR)):
            print ('GZIP: Offset found', i)
            with open(DECOMPRESSION_CHAMBER_PATH + '/result-gz-' + str(i) + '.bin', 'wb') as result:
                result.write(unzipped);
                result.close()
                break
        
fname = sys.argv[1]
with open(fname, 'rb') as compressed_data:
    compressed_data = compressed_data.read()
    thread_zlib = threading.Thread(target=do_zlib, args=(copy.copy(compressed_data),))
    thread_lzma = threading.Thread(target=do_lzma, args=(copy.copy(compressed_data),))
    thread_bz2 = threading.Thread(target=do_bz2, args=(copy.copy(compressed_data),))
    thread_zlib.start()
    thread_lzma.start()
    thread_bz2.start()
    thread_zlib.join()
    thread_lzma.join()
    thread_bz2.join()