CVE-2020-19802
📋 TL;DR
This vulnerability allows remote attackers to upload malicious files to Milken DoyoCMS v2.3 systems, potentially leading to arbitrary code execution. Attackers can exploit the upload file type parameter to bypass security controls. All users running DoyoCMS v2.3 are affected.
💻 Affected Systems
- Milken DoyoCMS
📦 What is this software?
Doyocms by Doyocms Project
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with attacker gaining full control over the web server, data exfiltration, and lateral movement to other systems.
Likely Case
Webshell deployment leading to data theft, defacement, or use as a foothold for further attacks.
If Mitigated
Attack blocked at the web application firewall level with no file execution possible.
🎯 Exploit Status
File upload vulnerabilities are commonly exploited and require minimal technical skill.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: No official vendor advisory found
Restart Required: No
Instructions:
No official patch available. Consider upgrading to a newer version if available or implementing workarounds.
🔧 Temporary Workarounds
File Upload Restriction
allImplement strict file type validation and whitelist only allowed extensions
Modify upload handling code to validate file extensions and MIME types
Web Application Firewall Rules
allBlock malicious file upload attempts at the WAF level
Configure WAF to block requests with suspicious file extensions in upload parameters
🧯 If You Can't Patch
- Disable file upload functionality entirely if not required
- Implement network segmentation to isolate the vulnerable system
🔍 How to Verify
Check if Vulnerable:
Check if running DoyoCMS v2.3 by examining version files or admin panelCheck Version:
Check version.txt or similar files in the DoyoCMS installation directoryVerify 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 suspicious extensions
- Multiple failed upload attempts
- POST requests to upload endpoints with unusual parameters
Network Indicators:
- HTTP POST requests to upload endpoints with unusual file extensions
- Traffic patterns indicating file upload attempts
SIEM Query:
source="web_server" AND (method="POST" AND uri="*upload*" AND (file_extension="php" OR file_extension="jsp" OR file_extension="asp"))