CVE-2020-18178
📋 TL;DR
CVE-2020-18178 is a critical path traversal vulnerability in HongCMS v4.0.0 that allows remote attackers to read, modify, or delete arbitrary files on the server via crafted POST requests to the language/ajax endpoint. This affects all HongCMS v4.0.0 installations with the admin interface accessible.
💻 Affected Systems
- HongCMS
📦 What is this software?
Hongcms by Hongcms Project
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise including sensitive file disclosure, website defacement, data destruction, or remote code execution by overwriting critical system files.
Likely Case
Unauthorized access to configuration files, database credentials, and sensitive user data leading to data breach and potential privilege escalation.
If Mitigated
Limited impact if proper file permissions, web application firewalls, and network segmentation are implemented.
🎯 Exploit Status
Exploitation requires sending crafted POST requests to /hcms/admin/index.php/language/ajax with directory traversal sequences in parameters.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v4.0.1 or later
Vendor Advisory: https://github.com/Neeke/HongCMS/issues/11
Restart Required: No
Instructions:
1. Backup current installation. 2. Download latest HongCMS version from official repository. 3. Replace vulnerable files with patched versions. 4. Verify language/ajax endpoint no longer accepts path traversal sequences.
🔧 Temporary Workarounds
Block vulnerable endpoint
allRestrict access to the vulnerable /hcms/admin/index.php/language/ajax endpoint using web server configuration.
# Apache: RewriteRule ^hcms/admin/index\.php/language/ajax - [F]
# Nginx: location ~* /hcms/admin/index\.php/language/ajax { deny all; }
Implement input validation
allAdd input validation to sanitize file path parameters before processing.
# PHP example: $file = basename($_POST['file']); // Sanitize input
🧯 If You Can't Patch
- Implement strict file permissions (read-only for web user on sensitive directories)
- Deploy web application firewall with path traversal detection rules
🔍 How to Verify
Check if Vulnerable:
Test by sending POST request to /hcms/admin/index.php/language/ajax with traversal payload like ../../../etc/passwd and checking response.Check Version:
Check HongCMS version in admin panel or examine version.php file in installation directory.Verify Fix Applied:
Attempt same traversal payload after patch - should return error or sanitized response instead of file contents.📡 Detection & Monitoring
Log Indicators:
- POST requests to /hcms/admin/index.php/language/ajax with ../ sequences in parameters
- Unusual file access patterns from web user
Network Indicators:
- HTTP POST requests containing directory traversal sequences (../, ..\) to the vulnerable endpoint
SIEM Query:
source="web_logs" AND uri_path="/hcms/admin/index.php/language/ajax" AND (http_method="POST") AND (payload="*../*" OR payload="*..\\*")