Challenge 4: PW Crack 4

Description

Can you crack the password to get the flag? Download the password checker here and you’ll need the encrypted flag and the hash in the same directory too. There are 100 potential passwords with only 1 being correct. You can find these by examining the password checker script.

Tags

Beginner picoMini 2022 General Skills password_cracking hashing

Points

100

Solution

In this challenge we are given a script and an encrypted flag. also we are given a hash file. The script is a simple password checker, if we entered the correct password it will print the flag. if we take a look at the script. we will find it almost identical to the previous challenge. the only difference is the number of potential passwords. we can use the same method to solve this challenge.

import hashlib

correct_pw_hash = open('level4.hash.bin', 'rb').read()

def hash_pw(pw_str):
    pw_bytes = bytearray()
    pw_bytes.extend(pw_str.encode())
    m = hashlib.md5()
    m.update(pw_bytes)
    return m.digest()

pos_pw_list = ["8c86", "7692", "a519", "3e61", "7dd6", "8919", "aaea", "f34b", "d9a2", "39f7", "626b", "dc78", "2a98", "7a85", "cd15", "80fa", "8571", "2f8a", "2ca6", "7e6b", "9c52", "7423", "a42c", "7da0", "95ab", "7de8", "6537", "ba1e", "4fd4", "20a0", "8a28", "2801", "2c9a", "4eb1", "22a5", "c07b", "1f39", "72bd", "97e9", "affc", "4e41", "d039", "5d30", "d13f", "c264", "c8be", "2221", "37ea", "ca5f", "fa6b", "5ada", "607a", "e469", "5681", "e0a4", "60aa", "d8f8", "8f35", "9474", "be73", "ef80", "ea43", "9f9e", "77d7", "d766", "55a0", "dc2d", "a970", "df5d", "e747", "dc69", "cc89", "e59a", "4f68", "14ff", "7928", "36b9", "eac6", "5c87", "da48", "5c1d", "9f63", "8b30", "5534", "2434", "4a82", "d72c", "9b6b", "73c5", "1bcf", "c739", "6c31", "e138", "9e77", "ace1", "2ede", "32e0", "3694", "fc92", "a7e2"]

for pw in pos_pw_list:
    if hash_pw(pw) == correct_pw_hash:
        print("The password is: " + pw)

If we run the script we just wrote we will get the correct password. 607a We can run the script again to get the flag.

$ python3 level4.py
Please enter correct password for flag: 607a

Welcome back... your flag, user:
picoCTF{fl45h_5pr1ng1ng_d770d48c}

Flag

picoCTF{fl45h_5pr1ng1ng_d770d48c}