CVE-2020-18261
📋 TL;DR
CVE-2020-18261 is a critical arbitrary file upload vulnerability in ED01-CMS v1.0 that allows attackers to upload malicious files through the image upload function. This enables remote code execution, potentially giving attackers full control over affected systems. Anyone running ED01-CMS v1.0 is vulnerable to this attack.
💻 Affected Systems
- ED01-CMS
📦 What is this software?
Ed01 Cms by Ed01 Cms Project
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with attacker gaining root/admin access, data exfiltration, ransomware deployment, and persistent backdoor installation.
Likely Case
Web server compromise leading to website defacement, data theft, and use of the server for further attacks like phishing or malware distribution.
If Mitigated
Attack blocked at web application firewall level with no successful file uploads reaching the server.
🎯 Exploit Status
The GitHub issue shows proof of concept exploitation. The vulnerability is simple to exploit with basic web attack tools.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: Not available
Restart Required: No
Instructions:
No official patch exists. Consider migrating to alternative CMS solutions or implementing strict file upload controls.
🔧 Temporary Workarounds
File Upload Restriction
allImplement strict file type validation and extension filtering for uploads
Web Application Firewall Rules
allBlock file uploads with executable extensions and suspicious content
🧯 If You Can't Patch
- Disable file upload functionality completely in ED01-CMS
- Isolate the ED01-CMS instance in a DMZ with strict network segmentation
🔍 How to Verify
Check if Vulnerable:
Check if running ED01-CMS v1.0 by examining the CMS version in admin panel or source codeCheck Version:
Check ED01-CMS configuration files or admin interface for version informationVerify Fix Applied:
Test file upload functionality with various file types to ensure only allowed extensions are accepted📡 Detection & Monitoring
Log Indicators:
- Unusual file uploads with executable extensions
- Multiple failed upload attempts
- Uploads of files with double extensions
Network Indicators:
- HTTP POST requests to upload endpoints with unusual file types
- Traffic patterns showing file uploads followed by command execution
SIEM Query:
source="web_server" AND (uri="*upload*" OR uri="*image*" OR method="POST") AND (file_extension="php" OR file_extension="jsp" OR file_extension="asp" OR file_extension="exe")