CVE-2025-67848
📋 TL;DR
This authentication bypass vulnerability in Moodle allows suspended users to authenticate through the LTI Provider, enabling unauthorized access to the system. This affects Moodle instances using LTI authentication where user suspension is a security control.
💻 Affected Systems
- Moodle
📦 What is this software?
Moodle by Moodle
Moodle by Moodle
Moodle by Moodle
Moodle by Moodle
Moodle by Moodle
⚠️ Risk & Real-World Impact
Worst Case
Suspended malicious users regain full access to the platform, potentially accessing sensitive student data, modifying grades, or disrupting learning activities.
Likely Case
Suspended users bypass restrictions to access course materials, submit assignments, or participate in forums they should be blocked from.
If Mitigated
Minimal impact if LTI authentication is disabled or suspended users have limited permissions even when authenticated.
🎯 Exploit Status
Exploitation requires a suspended user account and LTI authentication access
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Moodle security advisory for specific fixed version
Vendor Advisory: https://moodle.org/mod/forum/discuss.php?d=471298
Restart Required: No
Instructions:
1. Check Moodle security advisory for patch version. 2. Update Moodle to the patched version. 3. Verify LTI authentication now properly checks user suspension status.
🔧 Temporary Workarounds
Disable LTI Provider Authentication
allTemporarily disable LTI authentication until patch is applied
Navigate to Site administration > Plugins > Authentication > Manage authentication
Disable LTI Provider authentication method
Restrict LTI Access
allLimit LTI authentication to specific trusted sources only
Configure LTI tool settings to restrict to approved external tools only
🧯 If You Can't Patch
- Monitor authentication logs for suspended users authenticating via LTI
- Implement additional access controls for suspended user accounts
🔍 How to Verify
Check if Vulnerable:
Test if a suspended user account can authenticate through LTI ProviderCheck Version:
Check Moodle version in Site administration > General > About MoodleVerify Fix Applied:
Verify suspended users are properly blocked when attempting LTI authentication📡 Detection & Monitoring
Log Indicators:
- Suspended user accounts successfully authenticating via LTI
- Unusual LTI authentication patterns
Network Indicators:
- LTI authentication requests from unexpected sources
SIEM Query:
auth_method="LTI" AND user_status="suspended" AND result="success"