CVE-2025-3638
📋 TL;DR
This CSRF vulnerability in Moodle's Brickfield tool allows attackers to trick authenticated users into unknowingly submitting analysis requests. Any Moodle instance with the Brickfield tool enabled is affected, potentially allowing unauthorized content analysis.
💻 Affected Systems
- Moodle
📦 What is this software?
Moodle by Moodle
Moodle by Moodle
Moodle by Moodle
Moodle by Moodle
⚠️ Risk & Real-World Impact
Worst Case
Attackers could force administrators to analyze arbitrary content, potentially exposing sensitive course data or causing denial of service through resource exhaustion.
Likely Case
Unauthorized analysis requests submitted through administrator accounts, potentially revealing course structure or content metadata.
If Mitigated
Limited impact with proper CSRF protections and user awareness training.
🎯 Exploit Status
Requires authenticated user interaction but CSRF attacks are well-understood and easy to implement
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Moodle security advisory for specific version
Vendor Advisory: https://moodle.org/mod/forum/discuss.php?d=467600
Restart Required: No
Instructions:
1. Check Moodle security advisory for patched version. 2. Update Moodle to patched version. 3. Verify Brickfield tool functionality.
🔧 Temporary Workarounds
Disable Brickfield Tool
allTemporarily disable the Brickfield accessibility analysis tool
Navigate to Site administration > Plugins > Activity modules > Brickfield accessibility review > Disable
Implement Additional CSRF Protections
allAdd custom CSRF token validation for Brickfield endpoints
🧯 If You Can't Patch
- Restrict access to Brickfield tool to trusted administrators only
- Implement web application firewall rules to detect CSRF patterns
🔍 How to Verify
Check if Vulnerable:
Check if Moodle version is affected and Brickfield tool is enabled in Site administrationCheck Version:
Check Moodle version in Site administration > Notifications or via moodle/admin/index.phpVerify Fix Applied:
Verify Moodle version is updated to patched version and test Brickfield analysis functionality📡 Detection & Monitoring
Log Indicators:
- Multiple analysis requests from same user in short timeframe
- Analysis requests without proper referrer headers
Network Indicators:
- POST requests to Brickfield endpoints without CSRF tokens
- Unusual analysis request patterns
SIEM Query:
web_access_logs WHERE url CONTAINS 'brickfield' AND NOT (referrer CONTAINS 'moodle' OR parameters CONTAINS 'sesskey')