CVE-2020-36141
📋 TL;DR
CVE-2020-36141 is an unrestricted file upload vulnerability in BloofoxCMS that allows attackers to bypass MIME type validation by inserting 'image/jpeg' in the Content-Type header. This enables malicious file uploads that could lead to remote code execution. All users running vulnerable versions of BloofoxCMS are affected.
💻 Affected Systems
- BloofoxCMS
📦 What is this software?
Bloofoxcms by Bloofox
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, and lateral movement within the network.
Likely Case
Webshell deployment allowing persistent access, data exfiltration, and further exploitation of the server.
If Mitigated
File uploads blocked or properly validated, preventing malicious file execution.
🎯 Exploit Status
Exploitation requires only web access and knowledge of the bypass technique. Public details available in referenced advisory.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not specified
Vendor Advisory: https://muteb.io/2020/12/29/BloofoxCMS-Multiple-Vulnerabilities.html
Restart Required: No
Instructions:
No official patch available. Consider upgrading to a newer version if available or implementing workarounds.
🔧 Temporary Workarounds
Implement strict file upload validation
allAdd server-side validation that checks file extensions, MIME types, and file signatures independently
Restrict upload directory permissions
linuxSet upload directory to non-executable and restrict access
chmod 644 /path/to/uploads/*
chmod 755 /path/to/uploads/
🧯 If You Can't Patch
- Disable file upload functionality completely in BloofoxCMS configuration
- Implement web application firewall rules to block suspicious file uploads and Content-Type manipulation
🔍 How to Verify
Check if Vulnerable:
Check if running BloofoxCMS version 0.5.2.1 or earlier. Test file upload with Content-Type: image/jpeg header containing malicious payload.Check Version:
Check BloofoxCMS configuration files or admin panel for version informationVerify Fix Applied:
Attempt to upload a file with Content-Type: image/jpeg containing executable code. Successful upload indicates vulnerability.📡 Detection & Monitoring
Log Indicators:
- Multiple file upload attempts with Content-Type: image/jpeg
- Uploads of files with suspicious extensions (.php, .jsp, .asp)
Network Indicators:
- HTTP POST requests to upload endpoints with manipulated Content-Type headers
- Unusual file upload patterns
SIEM Query:
source="web_logs" AND (http_method="POST" AND uri="*upload*" AND content_type="*image/jpeg*")