CVE-2018-18626
📋 TL;DR
This vulnerability in PHPYun V4.6 allows authenticated administrators to delete arbitrary files and directories on the server via a SQL parameter manipulation in the database management interface. The flaw exists in the del_action() function which improperly handles user input. Only PHPYun installations with administrative access are affected.
💻 Affected Systems
- PHPYun
📦 What is this software?
Phpyun by Phpyun
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise through deletion of critical system files, configuration files, or web application files leading to denial of service, data loss, or privilege escalation.
Likely Case
Unauthorized deletion of application files, configuration files, or user data leading to service disruption and potential data loss.
If Mitigated
Limited impact with proper file permissions and administrative access controls preventing exploitation.
🎯 Exploit Status
Exploitation requires administrative credentials. The vulnerability is well-documented with public proof-of-concept available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: V4.7 or later
Vendor Advisory: Unknown
Restart Required: No
Instructions:
1. Upgrade PHPYun to version 4.7 or later. 2. If upgrade not possible, apply the security patch from the vendor. 3. Verify the fix by testing the vulnerable endpoint.
🔧 Temporary Workarounds
Restrict Administrative Access
allLimit administrative interface access to trusted IP addresses only
# Configure web server to restrict access to admin directory
# Apache: Use Require ip directive in .htaccess
# Nginx: Use allow/deny directives in server block
Input Validation
allAdd input validation to the del_action() function to restrict file deletion paths
# Modify admin/model/database.class.php
# Add path validation before file deletion operations
# Restrict deletions to specific directories only
🧯 If You Can't Patch
- Implement strict access controls for administrative interface (IP whitelisting, VPN access only)
- Regularly backup critical files and monitor file deletion activities in system logs
🔍 How to Verify
Check if Vulnerable:
Check if PHPYun version is 4.6. Attempt to access admin/index.php?m=database&c=del with administrative credentials and test file deletion.Check Version:
Check PHPYun version in admin panel or examine application files for version informationVerify Fix Applied:
After patching, test the vulnerable endpoint to confirm file deletion no longer works with arbitrary paths.📡 Detection & Monitoring
Log Indicators:
- Unusual file deletion patterns in system logs
- Multiple requests to admin/index.php?m=database&c=del with different parameters
- Administrative login from unusual locations
Network Indicators:
- HTTP requests to admin/index.php?m=database&c=del with suspicious parameters
- Unusual administrative interface access patterns
SIEM Query:
source="web_logs" AND uri="/admin/index.php" AND parameters CONTAINS "m=database&c=del" AND parameters CONTAINS "sql="