CVE-2025-31676
📋 TL;DR
A weak authentication vulnerability in Drupal's Email TFA module allows attackers to brute force two-factor authentication codes. This affects Drupal sites using Email TFA module versions before 2.0.3, potentially compromising user accounts with weak or predictable TFA codes.
💻 Affected Systems
- Drupal Email TFA module
📦 What is this software?
Email Tfa by Email Tfa Project
⚠️ Risk & Real-World Impact
Worst Case
Attackers bypass two-factor authentication entirely, gaining unauthorized access to administrative accounts and compromising the entire Drupal site.
Likely Case
Attackers brute force weak TFA codes to gain access to user accounts, potentially escalating privileges or accessing sensitive data.
If Mitigated
With rate limiting and strong TFA code policies, attackers would need significantly more time and resources to succeed, reducing successful compromise likelihood.
🎯 Exploit Status
Requires knowledge of valid usernames and ability to send authentication requests.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.0.3
Vendor Advisory: https://www.drupal.org/sa-contrib-2025-001
Restart Required: No
Instructions:
1. Update Drupal Email TFA module to version 2.0.3 or later. 2. Run database updates if required. 3. Clear Drupal caches.
🔧 Temporary Workarounds
Implement rate limiting
allConfigure web server or Drupal to limit authentication attempts per IP/user
Disable Email TFA module
DrupalTemporarily disable the vulnerable module until patched
drush pm-disable email_tfa
🧯 If You Can't Patch
- Implement strict rate limiting on authentication endpoints
- Monitor authentication logs for brute force patterns and block suspicious IPs
🔍 How to Verify
Check if Vulnerable:
Check Email TFA module version in Drupal admin interface or via drush: drush pm-list | grep email_tfaCheck Version:
drush pm-list --fields=name,version | grep email_tfaVerify Fix Applied:
Confirm Email TFA module version is 2.0.3 or higher📡 Detection & Monitoring
Log Indicators:
- Multiple failed TFA authentication attempts from single IP/user
- Unusual authentication patterns outside business hours
Network Indicators:
- High volume of POST requests to TFA endpoints
- Traffic spikes to /user/login/tfa paths
SIEM Query:
source="drupal_access.log" AND (uri_path="/user/login/tfa" OR uri_path="/tfa") AND status="403" | stats count by src_ip