CVE-2020-16629
📋 TL;DR
CVE-2020-16629 is a critical SQL injection vulnerability in PhpOK CMS that allows attackers to inject malicious SQL through attachment data, then use the attachment replacement function to write arbitrary PHP files to the server. This enables remote code execution on affected systems. All users running vulnerable versions of PhpOK are affected.
💻 Affected Systems
- PhpOK CMS
📦 What is this software?
Phpok by Phpok
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with remote code execution, allowing attackers to install backdoors, steal data, deface websites, or pivot to internal networks.
Likely Case
Website defacement, data theft, and installation of web shells for persistent access.
If Mitigated
Limited impact if proper input validation and file upload restrictions are in place, though SQL injection could still expose database contents.
🎯 Exploit Status
Public exploit code is available on GitHub, making this easily weaponizable by attackers with minimal technical skill.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 5.4.138 or later
Vendor Advisory: https://github.com/Gh0stF/phpok_cve/issues/1
Restart Required: No
Instructions:
1. Backup your current installation and database. 2. Download the latest version of PhpOK from the official source. 3. Replace all files except configuration files and uploads directory. 4. Verify the update by checking the version in admin panel.
🔧 Temporary Workarounds
Block api.php Access
allTemporarily block access to the vulnerable api.php endpoint
# For Apache: add to .htaccess
<Files "api.php">
Order allow,deny
Deny from all
</Files>
# For Nginx: add to server block
location ~ /api\.php$ {
deny all;
return 403;
}
Input Validation Filter
allAdd input validation for attachment parameters
# Add to relevant PHP files before SQL queries
$attachment_data = filter_var($_POST['attachment_data'], FILTER_SANITIZE_STRING);
🧯 If You Can't Patch
- Implement a Web Application Firewall (WAF) with SQL injection and file upload protection rules
- Restrict file permissions to prevent PHP file writing in upload directories
🔍 How to Verify
Check if Vulnerable:
Check if running PhpOK version 5.4.137 or earlier by examining the version in admin panel or checking PHP files for version strings.Check Version:
grep -r "5\.4\.137" /path/to/phpok/installation/ || php -r "include '/path/to/phpok/version.php'; echo $version;"Verify Fix Applied:
Verify version is 5.4.138 or later and test that api.php no longer accepts malicious SQL injection in attachment parameters.📡 Detection & Monitoring
Log Indicators:
- Unusual SQL queries in database logs
- Multiple failed attempts to access api.php with SQL patterns
- Unexpected PHP file creation in upload directories
Network Indicators:
- POST requests to api.php with SQL keywords in parameters
- Unusual file upload patterns to attachment endpoints
SIEM Query:
source="web_logs" AND (uri="/api.php" AND (param="*SELECT*" OR param="*UNION*" OR param="*INSERT*"))