CVE-2024-34007
📋 TL;DR
This CSRF vulnerability in MFA logout allows attackers to forcibly log out authenticated users by tricking them into clicking malicious links. It affects systems using the vulnerable MFA implementation, potentially disrupting legitimate user sessions and enabling follow-on attacks.
💻 Affected Systems
- Moodle
📦 What is this software?
Moodle by Moodle
⚠️ Risk & Real-World Impact
Worst Case
Attackers could mass-logout all users, causing widespread service disruption, then exploit the confusion to launch credential harvesting or session hijacking attacks against disoriented users.
Likely Case
Targeted logout of specific users (like administrators) to disrupt operations or enable social engineering attacks during the re-authentication process.
If Mitigated
Minimal impact if proper CSRF protections are in place elsewhere and users are trained to recognize phishing attempts.
🎯 Exploit Status
Exploitation requires user interaction (clicking malicious link) but is technically simple once the CSRF vector is identified
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Moodle security advisories for specific patched versions
Vendor Advisory: https://moodle.org/mod/forum/discuss.php?d=458396
Restart Required: No
Instructions:
1. Check Moodle security advisory for patched version
2. Update Moodle to the patched version
3. Verify MFA logout functionality includes CSRF tokens
🔧 Temporary Workarounds
CSRF Protection Enhancement
allManually add CSRF token validation to MFA logout endpoint
Requires code modification - consult Moodle development documentation for CSRF implementation
Logout Rate Limiting
allImplement rate limiting on logout requests to prevent mass exploitation
Configure web server or application firewall to limit logout requests per IP
🧯 If You Can't Patch
- Implement WAF rules to detect and block CSRF attempts against logout endpoints
- Educate users about phishing risks and implement session timeout policies to limit impact
🔍 How to Verify
Check if Vulnerable:
Test if MFA logout requests accept submissions without valid CSRF tokens by attempting a cross-site requestCheck Version:
Check Moodle version in administration panel or via moodle_version table in databaseVerify Fix Applied:
Confirm that MFA logout endpoints now require and validate CSRF tokens📡 Detection & Monitoring
Log Indicators:
- Multiple logout requests from single IP in short timeframe
- Logout requests without referrer headers or with suspicious referrers
Network Indicators:
- HTTP POST requests to logout endpoints without CSRF tokens
- Unusual patterns of logout activity
SIEM Query:
source="web_logs" AND (url_path="/logout" OR url_path="*/logout*") AND NOT csrf_token=* | stats count by src_ip