# Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one # or more contributor license agreements. Licensed under the Elastic License # 2.0; you may not use this file except in compliance with the Elastic License # 2.0. # Name: Encrypting files with 7zip # RTA: sevenzip_encrypted.py # ATT&CK: T1022 # Description: Uses "bin\.exe" to perform encryption of archives and archive headers. import base64 import os import sys from . import common SEVENZIP = common.get_path("bin", "7za.exe") def create_exfil(path=os.path.abspath("secret_stuff.txt")): common.log("Writing dummy exfil to %s" % path) with open(path, 'wb') as f: f.write(base64.b64encode(b"This is really secret stuff\n" * 100)) return path @common.requires_os(common.WINDOWS) @common.dependencies(SEVENZIP) def main(password="s0l33t"): # create 7z.exe with not-7zip name, and exfil svnz2 = os.path.abspath("a.exe") common.copy_file(SEVENZIP, svnz2) exfil = create_exfil() exts = ["7z", "zip", "gzip", "tar", "bz2", "bzip2", "xz"] out_jpg = os.path.abspath("out.jpg") for ext in exts: # Write archive for each type out_file = os.path.abspath("out." + ext) common.execute([svnz2, "a", out_file, "-p" + password, exfil], mute=True) common.remove_file(out_file) # Write archive for each type with -t flag if ext == "bz2": continue common.execute([svnz2, "a", out_jpg, "-p" + password, "-t" + ext, exfil], mute=True) common.remove_file(out_jpg) common.execute([SEVENZIP, "a", out_jpg, "-p" + password, exfil], mute=True) common.remove_files(exfil, svnz2, out_jpg) if __name__ == "__main__": exit(main(*sys.argv[1:]))