CVE-2020-19786
📋 TL;DR
This vulnerability allows attackers to upload malicious PHP files through CSZ CMS's file upload functionality, leading to remote code execution. It affects all users running CSKaza CSZ CMS versions before 1.2.4. Attackers can take full control of affected web servers.
💻 Affected Systems
- CSKaza CSZ CMS
📦 What is this software?
Csz Cms by Cszcms
⚠️ Risk & Real-World Impact
Worst Case
Complete server compromise allowing data theft, defacement, malware deployment, and lateral movement within the network.
Likely Case
Webshell installation leading to data exfiltration, credential harvesting, and use as attack platform.
If Mitigated
Limited impact with proper file upload restrictions and web application firewalls in place.
🎯 Exploit Status
Exploitation requires file upload access but is straightforward once obtained.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v1.2.4
Vendor Advisory: https://github.com/cskaza/cszcms/issues/20
Restart Required: No
Instructions:
1. Backup your database and files. 2. Download v1.2.4 from official repository. 3. Replace all files except config.php and uploads directory. 4. Run database update if needed.
🔧 Temporary Workarounds
File Upload Restriction
allRestrict file uploads to non-executable extensions and implement file type verification
Web Application Firewall
allDeploy WAF rules to block PHP file uploads and suspicious POST requests
🧯 If You Can't Patch
- Disable file upload functionality completely in CMS settings
- Implement strict file extension whitelisting and store uploaded files outside web root
🔍 How to Verify
Check if Vulnerable:
Check CMS version in admin panel or via version.php fileCheck Version:
grep -r 'CSZ CMS Version' /path/to/cszcms/ or check admin dashboardVerify Fix Applied:
Confirm version is 1.2.4 or later and test file upload with PHP extension📡 Detection & Monitoring
Log Indicators:
- File uploads with .php extensions
- Unusual POST requests to upload endpoints
- Webshell access patterns
Network Indicators:
- HTTP POST requests with PHP file content
- Outbound connections from web server to unknown IPs
SIEM Query:
source="web_logs" (url="*upload*" AND file_extension="php") OR (user_agent="*curl*" AND method="POST")