CVE-2021-40662
📋 TL;DR
This CSRF vulnerability in Chamilo LMS allows attackers to trick authenticated users into executing arbitrary commands on the server by clicking a malicious link. It affects Chamilo LMS administrators and users with sufficient privileges, potentially leading to full system compromise.
💻 Affected Systems
- Chamilo LMS
📦 What is this software?
Chamilo by Chamilo
⚠️ Risk & Real-World Impact
Worst Case
Complete system takeover through remote code execution, data theft, malware deployment, and lateral movement within the network.
Likely Case
Unauthorized command execution leading to data exfiltration, account compromise, or service disruption.
If Mitigated
Limited impact with proper CSRF protections, network segmentation, and least privilege principles in place.
🎯 Exploit Status
Exploit requires user to click crafted URL while authenticated; public proof-of-concept demonstrates RCE capability
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.11.15 and later
Restart Required: No
Instructions:
1. Backup your Chamilo installation and database. 2. Download Chamilo LMS 1.11.15 or later from official sources. 3. Replace affected files with patched versions. 4. Verify installation integrity.
🔧 Temporary Workarounds
CSRF Token Implementation
allAdd CSRF tokens to all state-changing requests
SameSite Cookie Attribute
allSet SameSite=Strict attribute on session cookies
Set-Cookie: session=value; SameSite=Strict; Secure; HttpOnly
🧯 If You Can't Patch
- Implement web application firewall (WAF) rules to detect and block CSRF attempts
- Restrict network access to Chamilo LMS to trusted IP ranges only
🔍 How to Verify
Check if Vulnerable:
Check Chamilo version via admin panel or by examining version files in installation directoryCheck Version:
Check /main/inc/conf/configuration.php or admin panel version displayVerify Fix Applied:
Verify installation of Chamilo 1.11.15 or later and test CSRF protections on form submissions📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to admin endpoints without referrer headers
- Multiple failed CSRF token validations
- Unexpected command execution in system logs
Network Indicators:
- Outbound connections to suspicious IPs following Chamilo access
- Unusual traffic patterns from Chamilo server
SIEM Query:
source="chamilo_logs" AND (event="csrf_failure" OR event="unauthorized_command")🔗 References
- https://febin0x4e4a.wordpress.com/2022/03/22/cve-2021-40662-chamilo-lms-1-11-14-rce/
- https://febinj.medium.com/cve-2021-40662-chamilo-lms-1-11-14-rce-5301bad245d7
- https://support.chamilo.org/projects/1/wiki/Security_issues#Issue-83-2021-08-11-High-impact-Moderate-risk-Cross-Site-Request-Forgery-CSRF-leading-to-Remote-Code-Execution
- https://febin0x4e4a.wordpress.com/2022/03/22/cve-2021-40662-chamilo-lms-1-11-14-rce/
- https://febinj.medium.com/cve-2021-40662-chamilo-lms-1-11-14-rce-5301bad245d7
- https://support.chamilo.org/projects/1/wiki/Security_issues#Issue-83-2021-08-11-High-impact-Moderate-risk-Cross-Site-Request-Forgery-CSRF-leading-to-Remote-Code-Execution
