CVE-2020-24930
📋 TL;DR
CVE-2020-24930 is an arbitrary file deletion vulnerability in Wuzhi CMS 4.0.1 backend. Attackers can delete any files on the server, potentially causing service disruption or data loss. This affects all deployments using the vulnerable version of Wuzhi CMS.
💻 Affected Systems
- Wuzhi CMS
📦 What is this software?
Wuzhicms by Wuzhicms
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise through deletion of critical system files, leading to OS corruption, data destruction, and permanent service outage.
Likely Case
Deletion of web application files causing website defacement, data loss, and service disruption requiring restoration from backups.
If Mitigated
Limited impact if proper file permissions and access controls prevent deletion of critical system files, though application files remain vulnerable.
🎯 Exploit Status
The vulnerability is documented in public GitHub issues with technical details. Attackers need backend access credentials to exploit.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown specific version, but fixes were implemented following the GitHub issue reports
Vendor Advisory: https://github.com/wuzhicms/wuzhicms/issues/191
Restart Required: No
Instructions:
1. Update to the latest version of Wuzhi CMS. 2. Review and apply any security patches mentioned in the GitHub issue. 3. Verify the vulnerable backend file has been fixed.
🔧 Temporary Workarounds
Restrict backend access
allLimit access to the CMS backend interface to trusted IP addresses only
# Example Apache .htaccess
Order deny,allow
Deny from all
Allow from 192.168.1.0/24
Allow from 10.0.0.0/8
File permission hardening
linuxSet restrictive permissions on critical directories and files
chmod 755 /var/www/html/
chmod 644 /var/www/html/*.php
chown www-data:www-data /var/www/html/
🧯 If You Can't Patch
- Implement strict access controls to the backend interface using IP whitelisting
- Monitor file deletion activities and implement file integrity monitoring
🔍 How to Verify
Check if Vulnerable:
Check if running Wuzhi CMS 4.0.1 and review the specific backend PHP file mentioned in vulnerability reportsCheck Version:
Check CMS version in admin panel or review version files in installation directoryVerify Fix Applied:
Verify CMS version is updated beyond 4.0.1 and test if arbitrary file deletion is possible from backend📡 Detection & Monitoring
Log Indicators:
- Unusual file deletion events in web server logs
- Multiple failed login attempts to backend followed by file operations
- PHP error logs showing file manipulation attempts
Network Indicators:
- Unusual traffic patterns to backend administration URLs
- Requests to file manipulation endpoints with suspicious parameters
SIEM Query:
source="web_server" AND (uri="*admin*" OR uri="*backend*") AND (action="delete" OR method="POST") AND status=200