CVE-2021-44673
📋 TL;DR
This vulnerability allows remote attackers to upload malicious web shell scripts through the file manager in Croogo CMS, leading to remote code execution. It affects Croogo 3.0.2 installations with the vulnerable admin/file-manager/attachments endpoint accessible.
💻 Affected Systems
- Croogo CMS
📦 What is this software?
Croogo by Croogo
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with attacker gaining full control over the web server, data exfiltration, lateral movement, and persistent backdoor installation.
Likely Case
Web shell upload leading to data theft, website defacement, or use as part of a botnet.
If Mitigated
Attack blocked at web application firewall or file upload validation layer with no impact.
🎯 Exploit Status
Exploitation requires authentication to admin interface but is straightforward once authenticated.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 3.0.3 or later
Vendor Advisory: https://github.com/croogo/croogo/releases
Restart Required: No
Instructions:
1. Backup your current installation. 2. Download Croogo 3.0.3 or later from official repository. 3. Replace all files except config and upload directories. 4. Clear cache if applicable.
🔧 Temporary Workarounds
Restrict admin access
allLimit access to admin interface using IP whitelisting or VPN.
# Example Apache .htaccess
Order deny,allow
Deny from all
Allow from 192.168.1.0/24
File upload validation
allImplement server-side file type validation for uploads.
# PHP example
$allowed_types = ['jpg', 'png', 'pdf'];
$ext = strtolower(pathinfo($filename, PATHINFO_EXTENSION));
if (!in_array($ext, $allowed_types)) { die('Invalid file type'); }
🧯 If You Can't Patch
- Disable or remove the file-manager/attachments functionality entirely.
- Implement web application firewall rules to block suspicious file uploads to the vulnerable endpoint.
🔍 How to Verify
Check if Vulnerable:
Check if running Croogo 3.0.2 and if admin/file-manager/attachments endpoint accepts file uploads without proper validation.Check Version:
Check composer.json or version file in Croogo installation directory.Verify Fix Applied:
Verify version is 3.0.3 or later and test that malicious file uploads to the endpoint are rejected.📡 Detection & Monitoring
Log Indicators:
- Unusual file uploads to admin/file-manager/attachments
- PHP/script files uploaded via file manager
- Multiple failed upload attempts
Network Indicators:
- POST requests to /admin/file-manager/attachments with executable file extensions
- Subsequent connections to uploaded suspicious files
SIEM Query:
source="web_logs" AND uri="/admin/file-manager/attachments" AND (file_extension="php" OR file_extension="jsp" OR file_extension="asp")