CVE-2020-18886
📋 TL;DR
This vulnerability allows remote attackers to upload arbitrary files to PHPMyWind v5.6 systems via the admin/upload_file_do.php component. Attackers can execute arbitrary code on the server by uploading malicious files like PHP shells. All PHPMyWind v5.6 installations with the vulnerable component accessible are affected.
💻 Affected Systems
- PHPMyWind
📦 What is this software?
Phpmywind by Phpmywind
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with remote code execution leading to data theft, ransomware deployment, or creation of persistent backdoors.
Likely Case
Webshell upload leading to unauthorized access, data exfiltration, and lateral movement within the network.
If Mitigated
File upload attempts blocked or sanitized, preventing malicious file execution.
🎯 Exploit Status
Simple file upload exploitation with publicly available proof-of-concept. No authentication required in default configurations.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: Not available
Restart Required: No
Instructions:
No official patch available. Consider upgrading to a newer version if available, or implement workarounds.
🔧 Temporary Workarounds
Restrict file upload access
allBlock access to the vulnerable upload_file_do.php component via web server configuration or firewall rules.
# Apache: Add to .htaccess
<Files "upload_file_do.php">
Order Allow,Deny
Deny from all
</Files>
# Nginx: Add to server block
location ~ /admin/upload_file_do\.php$ {
deny all;
return 403;
}
Implement file upload validation
allAdd server-side validation to restrict uploaded file types to safe extensions only.
# Example PHP validation snippet
$allowed_extensions = array('jpg', 'jpeg', 'png', 'gif', 'pdf');
$file_extension = strtolower(pathinfo($_FILES['file']['name'], PATHINFO_EXTENSION));
if (!in_array($file_extension, $allowed_extensions)) {
die('Invalid file type');
}
🧯 If You Can't Patch
- Implement strict network segmentation to isolate PHPMyWind from critical systems.
- Deploy web application firewall (WAF) with file upload protection rules.
🔍 How to Verify
Check if Vulnerable:
Check if /admin/upload_file_do.php exists and is accessible via HTTP requests. Test by attempting to upload a file with a PHP extension.Check Version:
Check PHPMyWind version in configuration files or admin panel. Look for version 5.6 in source code or documentation.Verify Fix Applied:
Verify that upload_file_do.php returns 403 Forbidden or is inaccessible. Test file upload functionality with malicious extensions to confirm blocking.📡 Detection & Monitoring
Log Indicators:
- HTTP POST requests to /admin/upload_file_do.php with file uploads
- Uploads of files with .php, .phtml, or other executable extensions
- Unusual file creation in upload directories
Network Indicators:
- POST requests to upload endpoints with unusual file types
- Traffic patterns indicating webshell communication
SIEM Query:
source="web_logs" AND uri="/admin/upload_file_do.php" AND (file_extension="php" OR file_extension="phtml")