CVE-2011-4906
📋 TL;DR
This vulnerability in Joomla! 1.5.x before 1.5.13 allows attackers to upload arbitrary files including PHP scripts through the TinyMCE editor's file browser component. This leads to remote code execution on the web server. Any Joomla! site using the vulnerable version with the TinyMCE editor enabled is affected.
💻 Affected Systems
- Joomla!
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete server compromise allowing attackers to execute arbitrary code, steal data, deface websites, or use the server as a pivot point for further attacks.
Likely Case
Website defacement, data theft, malware distribution, or installation of backdoors for persistent access.
If Mitigated
Limited impact if file uploads are restricted, web application firewalls block malicious uploads, and proper file permissions prevent execution.
🎯 Exploit Status
Exploitation requires authentication to access the TinyMCE editor interface. Multiple public exploits exist.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.5.13
Vendor Advisory: https://developer.joomla.org/security/news/301-20090722-core-file-upload.html
Restart Required: No
Instructions:
1. Backup your Joomla! site and database. 2. Download Joomla! 1.5.13 or later. 3. Replace all files with the new version. 4. Run any database update scripts if provided. 5. Test functionality.
🔧 Temporary Workarounds
Disable TinyMCE Editor
allDisable the TinyMCE editor in Joomla! configuration to remove the vulnerable component.
Navigate to Joomla! Administrator > Site > Global Configuration > Site tab > Set Default Editor to 'No Editor' or another editor
Restrict File Uploads
linuxConfigure web server to block PHP file uploads through the TinyMCE file browser.
Add to .htaccess: <FilesMatch "\.(php|php3|php4|php5|phtml|pl|py|jsp|asp|htm|html|shtml|sh|cgi)$">
Deny from all
</FilesMatch>
🧯 If You Can't Patch
- Implement strict file upload validation and filtering at the web application firewall level.
- Restrict access to the TinyMCE editor interface to trusted IP addresses only.
🔍 How to Verify
Check if Vulnerable:
Check Joomla! version in administrator panel or examine includes/version.php file for version number.Check Version:
cat includes/version.php | grep "RELEASE"Verify Fix Applied:
Confirm version is 1.5.13 or later and test that file uploads through TinyMCE are properly validated.📡 Detection & Monitoring
Log Indicators:
- Unusual file uploads to TinyMCE directories
- PHP file creation in upload directories
- Multiple failed authentication attempts followed by successful login
Network Indicators:
- POST requests to TinyMCE file upload endpoints with PHP files
- Unusual outbound connections from web server
SIEM Query:
source="web_logs" AND (uri="/plugins/editors/tinymce/jscripts/tiny_mce/plugins/filemanager/upload.php" OR uri CONTAINS "tinymce/upload") AND (file_ext="php" OR file_ext="php3" OR file_ext="php4" OR file_ext="php5")🔗 References
- https://developer.joomla.org/security/news/301-20090722-core-file-upload.html
- https://www.exploit-db.com/exploits/10183
- https://www.openwall.com/lists/oss-security/2011/12/25/7
- https://developer.joomla.org/security/news/301-20090722-core-file-upload.html
- https://www.exploit-db.com/exploits/10183
- https://www.openwall.com/lists/oss-security/2011/12/25/7
