CVE-2022-23048
📋 TL;DR
This vulnerability allows authenticated admin users in Exponent CMS to upload malicious ZIP files containing PHP scripts, which are then extracted to a web-accessible directory enabling remote code execution. It affects Exponent CMS installations with admin accounts that have theme/extension upload privileges. The attack requires admin credentials but leads to full server compromise.
💻 Affected Systems
- Exponent CMS
📦 What is this software?
Exponent Cms by Exponentcms
⚠️ Risk & Real-World Impact
Worst Case
Complete server takeover with attacker gaining shell access, installing backdoors, stealing data, and pivoting to other systems.
Likely Case
Attacker uploads web shell, executes arbitrary commands, defaces website, or installs cryptocurrency miners.
If Mitigated
Attack prevented by proper access controls, file upload restrictions, or web application firewall rules.
🎯 Exploit Status
Exploitation requires admin credentials but is straightforward once authenticated. Public proof-of-concept demonstrates the attack chain.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.6.0patch3 or later
Vendor Advisory: https://exponentcms.lighthouseapp.com/projects/61783/tickets/1460
Restart Required: No
Instructions:
1. Backup your Exponent CMS installation and database. 2. Download the latest version from the official repository. 3. Replace all files except /files and /themes directories. 4. Run the upgrade script if prompted. 5. Verify the patch by checking version number.
🔧 Temporary Workarounds
Restrict Theme Upload Permissions
allRemove theme/extension upload capabilities from admin accounts
Edit user permissions in Exponent CMS admin panel to disable 'upload themes' and 'install extensions'
Block PHP Execution in Themes Directory
linuxConfigure web server to prevent PHP execution in themes directory
For Apache: Add 'php_flag engine off' to .htaccess in /themes directory
For Nginx: Add 'location ~ /themes/.*\.php$ { deny all; }' to site config
🧯 If You Can't Patch
- Implement strict access controls and monitor admin account activity
- Deploy web application firewall with file upload restrictions and PHP execution blocking
🔍 How to Verify
Check if Vulnerable:
Check Exponent CMS version in admin panel or via /exponent_version.php. Versions 2.6.0patch2 or earlier are vulnerable.Check Version:
Check admin dashboard or view source of /exponent_version.phpVerify Fix Applied:
Verify version is 2.6.0patch3 or later. Test by attempting to upload a ZIP file with PHP content - should be rejected.📡 Detection & Monitoring
Log Indicators:
- ZIP file uploads to themes directory
- PHP file creation in /themes/simpletheme/
- Unusual admin account activity
Network Indicators:
- HTTP POST requests to upload endpoints with ZIP files
- Requests to PHP files in themes directory
SIEM Query:
source="web_logs" AND (uri_path="/themes/simpletheme/*.php" OR method="POST" AND uri_path CONTAINS "upload")🔗 References
- https://exponentcms.lighthouseapp.com/projects/61783/tickets/1460
- https://fluidattacks.com/advisories/dylan/
- https://github.com/exponentcms/exponent-cms/issues/1546
- https://exponentcms.lighthouseapp.com/projects/61783/tickets/1460
- https://fluidattacks.com/advisories/dylan/
- https://github.com/exponentcms/exponent-cms/issues/1546
