CVE-2023-2288
📋 TL;DR
The Otter WordPress plugin before version 2.2.6 contains a PHAR deserialization vulnerability that allows attackers to execute arbitrary code on vulnerable systems. This affects WordPress sites running PHP versions below 8.0 with the vulnerable plugin installed. Attackers can exploit this by uploading malicious files that trigger deserialization when accessed.
💻 Affected Systems
- Otter WordPress plugin
📦 What is this software?
Otter by Themeisle
⚠️ Risk & Real-World Impact
Worst Case
Full server compromise leading to data theft, ransomware deployment, or complete site takeover
Likely Case
Remote code execution allowing backdoor installation, data exfiltration, or site defacement
If Mitigated
Limited impact with proper file upload restrictions and PHP version controls
🎯 Exploit Status
Exploitation requires file upload capability but no authentication
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.2.6
Vendor Advisory: https://wpscan.com/vulnerability/93acb4ee-1053-48e1-8b69-c09dc3b2f302
Restart Required: No
Instructions:
1. Log into WordPress admin panel
2. Navigate to Plugins → Installed Plugins
3. Find Otter plugin and update to version 2.2.6 or higher
4. Verify update completed successfully
🔧 Temporary Workarounds
Upgrade PHP to 8.0+
linuxPHAR deserialization vulnerability is mitigated in PHP 8.0+
sudo apt update && sudo apt install php8.0
sudo systemctl restart apache2
Disable file uploads
allPrevent file uploads to block exploitation vector
Add 'php_flag file_uploads off' to .htaccess
🧯 If You Can't Patch
- Disable or remove the Otter plugin entirely
- Implement strict WAF rules to block phar:// protocol usage
🔍 How to Verify
Check if Vulnerable:
Check WordPress admin panel → Plugins → Otter version numberCheck Version:
wp plugin list --name=otter --field=versionVerify Fix Applied:
Confirm Otter plugin version is 2.2.6 or higher📡 Detection & Monitoring
Log Indicators:
- Unusual file uploads to WordPress media library
- phar:// protocol usage in access logs
- POST requests to plugin endpoints with file parameters
Network Indicators:
- HTTP requests containing phar:// strings
- File uploads to WordPress with unusual extensions
SIEM Query:
source="web_access.log" AND "phar://"