Challenge 25: PW Crack 5

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. Here’s a dictionary with all possible passwords based on the password conventions we’ve seen so far.

Tags

Beginner picoMini 2022 General Skills password_cracking hashing

Points

100

Solution

This challenge is similar to the previous one. We are given a script and an encrypted flag. also we are given a hash file. but this time we are given a dictionary file that contains lots of possible passwords.

We can use the same script to check the passwords. but this time we need to check all the passwords in the dictionary file.

import hashlib

correct_pw_hash = open('level5.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 = open('dictionary.txt', 'r').read().splitlines()

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

if we run the script we will get the password.

$ python3 crack.py
The password is: 9581

Now we can use the password to decrypt the flag.

$ python3 level5.py
Please enter correct password for flag: 9581

Welcome back... your flag, user:
picoCTF{h45h_sl1ng1ng_36e992a6}

Flag

picoCTF{h45h_sl1ng1ng_36e992a6}