inflate.py

# Original source: https://github.com/njcve/inflate.py/tree/main
# File inflator to incease size of payload to help bypass AV/EDR 
import sys
import struct
import argparse
import shutil # file copy

def main(args=sys.argv[1:]):
    parser = argparse.ArgumentParser(description='PE file inflator - Inflates file with null bytes at the end of file')
    parser.add_argument("-file", "-f", help="Target PE file to inflate (EXE, DLL, etc.)")
    parser.add_argument("-output", "-o", help="Output file to write inflated PE to")
    parser.add_argument("-size", "-s", help="Size in MB to inflate binary by (default = 10 mb)", default="10", type=int)
    args = parser.parse_args(args)

    inputFile = args.file
    output = args.output
    size = args.size

    # Check input parameters
    if not inputFile or not output:
        print("""[ERROR] - Enter an input and output file.\n
    Usage:
    python -f payload.exe -o outfile.exe -s 100       # Inflate an EXE 100 mb
    python -f library.dll -o outlibrary.dll -s 250    # Inflate a DLL 250 mb 
        """)
        sys.exit()

    # Do inflation
    inflate(inputFile, output, size)


# Inflation function
def inflate(file, outfile, size):
    print(f"[!] Inflating {file} by {size} mb")
    shutil.copyfile(file, outfile)

    blank_bytes = struct.pack('B', 0)
    transformer = open(outfile, 'ab')
    transformer.write(blank_bytes * 1024 * 1024 * size)
    transformer.close()
    
    print(f"[!] Inflating file by {size} megabytes")
    print(f"[!] Operation Complete. Written to output file '{outfile}'\n")


###########################################################################
if __name__ == '__main__':
    main()