CVE-2020-22151
📋 TL;DR
CVE-2020-22151 is a critical remote code execution vulnerability in Fuel-CMS that allows attackers to upload malicious zip files containing PHP code. This affects all systems running Fuel-CMS version 1.4.6 with the vulnerable upload function exposed. Attackers can gain complete control of affected web servers.
💻 Affected Systems
- Fuel-CMS
📦 What is this software?
Fuel Cms by Thedaylightstudio
⚠️ Risk & Real-World Impact
Worst Case
Complete server compromise allowing data theft, malware deployment, lateral movement, and persistent backdoor installation.
Likely Case
Webshell deployment leading to data exfiltration, defacement, and credential harvesting from the compromised server.
If Mitigated
Limited impact with proper file upload restrictions and web application firewalls blocking malicious payloads.
🎯 Exploit Status
Exploit requires crafting a malicious zip file with PHP code and uploading it via the vulnerable assets parameter. No authentication required.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Version 1.4.7 or later
Vendor Advisory: https://github.com/daylightstudio/FUEL-CMS/issues/551
Restart Required: No
Instructions:
1. Backup your current installation. 2. Download Fuel-CMS 1.4.7 or later from GitHub. 3. Replace vulnerable files with patched versions. 4. Verify upload functionality is properly secured.
🔧 Temporary Workarounds
Disable File Uploads
allTemporarily disable the vulnerable upload functionality in Fuel-CMS configuration
Edit fuel/application/config/config.php and set 'allow_upload' to false
Web Application Firewall Rule
allBlock requests containing zip files to the vulnerable upload endpoint
Add WAF rule: Block POST requests to */fuel/assets/upload* containing .zip files
🧯 If You Can't Patch
- Implement strict file upload validation rejecting zip files entirely
- Isolate Fuel-CMS instance behind reverse proxy with strict content filtering
🔍 How to Verify
Check if Vulnerable:
Check if running Fuel-CMS version 1.4.6 by examining the fuel/application/config/version.php fileCheck Version:
cat fuel/application/config/version.php | grep 'fuel_version'Verify Fix Applied:
Verify version is 1.4.7 or higher and test upload functionality with safe test files📡 Detection & Monitoring
Log Indicators:
- Multiple failed upload attempts
- POST requests to /fuel/assets/upload with zip files
- Unusual file creation in upload directories
Network Indicators:
- HTTP POST requests with zip file content to Fuel-CMS upload endpoints
- Outbound connections from web server to unknown IPs post-upload
SIEM Query:
source="web_logs" AND (uri_path="/fuel/assets/upload" AND method="POST" AND file_extension="zip")