CVE-2020-20951
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary commands on Pluck CMS servers through file upload functionality in the admin panel. It affects Pluck CMS version 4.7.10-dev2 specifically. Attackers can gain full control of affected systems.
💻 Affected Systems
- Pluck CMS
📦 What is this software?
Pluck by Pluck Cms
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attackers to execute arbitrary commands, steal data, install malware, pivot to other systems, and maintain persistent access.
Likely Case
Remote code execution leading to web server compromise, data exfiltration, and potential ransomware deployment.
If Mitigated
Limited impact if proper file upload validation and admin authentication are enforced, though risk remains if admin credentials are compromised.
🎯 Exploit Status
Exploitation requires admin credentials but is straightforward once authenticated.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4.7.11 or later
Vendor Advisory: https://github.com/pluck-cms/pluck/issues/84
Restart Required: No
Instructions:
1. Backup current installation. 2. Download latest version from official repository. 3. Replace vulnerable files with patched version. 4. Verify file upload functionality is properly validated.
🔧 Temporary Workarounds
Disable file uploads
allTemporarily disable file upload functionality in admin panel
Modify admin configuration to remove file upload options
Restrict admin access
allLimit admin panel access to specific IP addresses
Add IP restrictions to .htaccess or web server configuration
🧯 If You Can't Patch
- Implement strict file upload validation (allow only specific extensions, check file signatures)
- Enable WAF rules to block suspicious file upload patterns and command execution attempts
🔍 How to Verify
Check if Vulnerable:
Check Pluck CMS version in admin panel or by examining version files. Version 4.7.10-dev2 is vulnerable.Check Version:
Check includes/version.php or admin panel version displayVerify Fix Applied:
Verify version is 4.7.11 or later and test file upload functionality with malicious payloads.📡 Detection & Monitoring
Log Indicators:
- Unusual file uploads with suspicious extensions
- POST requests to upload endpoints with executable content
- System command execution in web server logs
Network Indicators:
- Unexpected outbound connections from web server
- Command and control traffic patterns
SIEM Query:
source="web_logs" AND (uri="*/admin/*upload*" AND (file_extension="php" OR file_extension="sh" OR file_extension="exe"))