CVE-2024-33997
📋 TL;DR
This stored cross-site scripting (XSS) vulnerability in Moodle's equation editor allows attackers to inject malicious scripts when editing another user's equation. The scripts execute in victims' browsers when they view the affected content. This affects Moodle administrators, teachers, and students who use the equation editor functionality.
💻 Affected Systems
- Moodle
📦 What is this software?
Moodle by Moodle
Moodle by Moodle
Moodle by Moodle
⚠️ Risk & Real-World Impact
Worst Case
Attackers could steal session cookies, perform actions as authenticated users, deface content, or redirect users to malicious sites, potentially leading to account compromise and data theft.
Likely Case
Attackers inject malicious JavaScript to steal session cookies or perform unauthorized actions within the victim's permissions, potentially compromising individual accounts.
If Mitigated
With proper input validation and output encoding, the risk is limited to minor content manipulation with no significant security impact.
🎯 Exploit Status
Exploitation requires the ability to edit another user's equation, which typically requires some level of access to the Moodle system.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not specified in provided references, but Moodle security updates address this
Vendor Advisory: https://moodle.org/mod/forum/discuss.php?d=458385
Restart Required: No
Instructions:
1. Update Moodle to the latest security release. 2. Apply the security patch for CVE-2024-33997. 3. Clear caches if required by the update process.
🔧 Temporary Workarounds
Disable Equation Editor
allTemporarily disable the equation editor functionality to prevent exploitation
Navigate to Site administration > Plugins > Text editors > Atto editor > Atto toolbar settings and remove the 'equation' button
Implement Content Security Policy
allAdd CSP headers to restrict script execution from untrusted sources
Add 'Content-Security-Policy: script-src 'self'' to web server configuration
🧯 If You Can't Patch
- Implement strict input validation and output encoding for equation editor content
- Monitor for suspicious equation content and user activity logs
🔍 How to Verify
Check if Vulnerable:
Check if your Moodle version is affected by reviewing the security advisory and comparing with your installed versionCheck Version:
Navigate to Site administration > Notifications in Moodle admin panel to check versionVerify Fix Applied:
After patching, test the equation editor functionality to ensure script injection is no longer possible📡 Detection & Monitoring
Log Indicators:
- Unusual equation editor activity
- Multiple failed equation edit attempts
- Suspicious script-like content in equation data
Network Indicators:
- Unexpected external script loads from equation content pages
SIEM Query:
Search for equation editor events containing script tags or JavaScript code patterns