CVE-2020-19267
📋 TL;DR
This vulnerability allows attackers to upload malicious PHP files to Dswjcms 1.6.4, leading to remote code execution. Attackers can take full control of affected web servers by exploiting improper file upload validation. All systems running the vulnerable version are affected.
💻 Affected Systems
- Dswjcms
📦 What is this software?
Dswjcms by Dswjcms Project
⚠️ Risk & Real-World Impact
Worst Case
Complete server compromise allowing data theft, malware deployment, lateral movement, and persistent backdoor installation.
Likely Case
Webshell upload leading to data exfiltration, defacement, or cryptocurrency mining operations.
If Mitigated
Unauthorized file upload blocked, maintaining normal system functionality with no compromise.
🎯 Exploit Status
Simple file upload bypass with publicly available proof-of-concept code.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: No
Instructions:
1. Check for official patch from Dswjcms developers
2. If no patch available, implement workarounds
3. Consider migrating to alternative CMS if unmaintained
🔧 Temporary Workarounds
File Upload Restriction
allRestrict file uploads to specific extensions and validate file types
Modify PHP configuration to restrict uploads: file_uploads = Off
Add .htaccess rules: <FilesMatch "\.(php|php5|php7|phtml)$">
Order Allow,Deny
Deny from all
</FilesMatch>
Endpoint Restriction
allBlock access to vulnerable endpoint
Apache: RewriteRule ^/index\.php/Dswjcms/Basis/resources - [F]
Nginx: location ~ /index\.php/Dswjcms/Basis/resources { return 403; }
🧯 If You Can't Patch
- Implement web application firewall (WAF) rules to block malicious file uploads
- Isolate the vulnerable system in a DMZ with strict network segmentation
🔍 How to Verify
Check if Vulnerable:
Check if Dswjcms version is 1.6.4 and test file upload functionality at /index.php/Dswjcms/Basis/resourcesCheck Version:
Check CMS configuration files or admin panel for version informationVerify Fix Applied:
Attempt to upload PHP file to vulnerable endpoint - should be rejected📡 Detection & Monitoring
Log Indicators:
- Unusual file uploads to /index.php/Dswjcms/Basis/resources
- PHP file uploads from unexpected sources
- Webshell creation in upload directories
Network Indicators:
- POST requests to vulnerable endpoint with file uploads
- Unusual outbound connections from web server
SIEM Query:
source="web_logs" AND (uri="/index.php/Dswjcms/Basis/resources" OR file_extension="php") AND http_method="POST"