Open a password protected RAR file from a RegEx pattern. The RegEx serves as hint to provide a list of password to try

crackRAR.py

"""
Brute force a password protected rar file with a RegEx pattern hint.

This is not meant to be used with malicious intent.

I have made this script only because I had a protected rar file for which I forget
the pwd but remembered partially what it was. Writing a RegEx helped to reduce the
pwd candidates to something I could easily fastly recover :)

Pre-requisites:
    - `pip install exrex rarfile`
    - have unrar available in your PATH
 
Usage:
    `python3 crackRAR.py -i INPUT_FILE -p PWD_PATTERN`

Example:
    `python3 crackRAR.py -i my_file.rar -p "my_awesome_[Rr][3e]gEX\!?"`

    Will try to open extract the file `my_file.rar` with the following passwords:
        my_awesome_regEX
        my_awesome_regEX!
        my_awesome_RegEX
        my_awesome_RegEX!
        my_awesome_r3gEX
        my_awesome_r3gEX!
        my_awesome_R3gEX
        my_awesome_R3gEX!
"""

import argparse
import os
import exrex

from rarfile import RarFile, BadRarFile
from tqdm import tqdm
from typing import Tuple


def parse_arguments() -> argparse.Namespace:
    """Parse the arguments."""
    parser = argparse.ArgumentParser(description="Parse command line arguments")

    parser.add_argument(
        "-i", "--input_file", type=str, required=True, help="Path to the input rar file"
    )
    parser.add_argument(
        "-p",
        "--pwd_pattern",
        type=str,
        required=True,
        help="The regex pattern matching the pwd.",
    )

    return parser.parse_args()


def tryExtractRar(file_path: str, pattern: str) -> Tuple[bool, str]:
    """Try to open the rar file.

    Args:
        file_path: the path to the protected rar file.
        pattern: the regex pattern to use to generate password candidates.

    Returns:
        ret: True on pwd found, False otherwise.
        pwd: the pwd to open the rar file. Can be ignored if ret is False.

    """
    # Generator pwd from the regex pattern
    pwd_gen = exrex.generate(pattern)
    # Number of password to try
    pwd_count = exrex.count(pattern)
    with RarFile(file_path, "r") as rar_file:
        pbar = tqdm(pwd_gen, total=pwd_count)
        for pwd in pbar:
            pbar.set_description(f"Processing '{pwd}'")
            try:
                # Try to extract
                rar_file.extractall(pwd=pwd)
                return True, pwd
            except BadRarFile:
                # The error occurs on bad password
                pass
    return False, ""


def __main():
    # Parse the arguments
    args = parse_arguments()

    # Check if the file exists
    if not os.path.exists(args.input_file):
        raise FileNotFoundError(f"File {args.input_file} does not exit!")

    # Try to find the password
    print("Start trying passwords")
    ret, pwd = tryExtractRar(args.input_file, args.pwd_pattern)

    if ret:
        print(f"The password is: {pwd}")
    else:
        print(f"Sorry, the password was not found from the provided RegEx: {args.pwd_pattern}")


if __name__ == "__main__":
    __main()