CVE-2020-35760
📋 TL;DR
CVE-2020-35760 is an unrestricted file upload vulnerability in bloofoxCMS that allows attackers to upload malicious PHP files. This can lead to remote code execution and complete system compromise. All users running bloofoxCMS 0.5.2.1 are affected.
💻 Affected Systems
- bloofoxCMS
📦 What is this software?
Bloofoxcms by Bloofox
⚠️ Risk & Real-World Impact
Worst Case
Complete system takeover via remote code execution, data theft, defacement, and lateral movement within the network.
Likely Case
Webshell deployment leading to data exfiltration, website defacement, and server compromise.
If Mitigated
File uploads blocked or properly validated, limiting impact to denial of service if upload attempts occur.
🎯 Exploit Status
Simple file upload bypass with no authentication required. Exploitation tools and scripts are widely available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: None - bloofoxCMS appears abandoned
Vendor Advisory: https://github.com/alexlang24/bloofoxCMS/issues/9
Restart Required: No
Instructions:
No official patch exists. Consider migrating to alternative CMS or implementing strict file upload validation.
🔧 Temporary Workarounds
File Upload Restriction
allImplement server-side file type validation and restrict uploads to safe extensions only
Modify upload handling code to validate file extensions and MIME types
Implement file content checking
Web Application Firewall Rules
allBlock PHP file uploads at the WAF level
Add WAF rule: deny requests with Content-Type containing 'php' in file uploads
Block file extensions: .php, .phtml, .php3, .php4, .php5, .php7
🧯 If You Can't Patch
- Disable file upload functionality completely in bloofoxCMS
- Implement network segmentation to isolate bloofoxCMS from critical systems
🔍 How to Verify
Check if Vulnerable:
Check if running bloofoxCMS version 0.5.2.1. Attempt to upload a PHP file through the CMS interface.Check Version:
Check CMS admin panel or read version files in installation directoryVerify Fix Applied:
Test file upload functionality with PHP files - they should be rejected. Verify file validation is implemented.📡 Detection & Monitoring
Log Indicators:
- File upload attempts with .php extensions
- Unusual POST requests to upload endpoints
- Webshell access patterns in access logs
Network Indicators:
- POST requests with PHP file uploads to CMS endpoints
- Outbound connections from CMS server to unknown IPs
SIEM Query:
source="web_logs" AND (uri_path="*upload*" OR uri_path="*admin*") AND (file_extension="php" OR file_extension="phtml")