CVE-2011-4908
📋 TL;DR
This vulnerability in the TinyBrowser plugin for Joomla! allows attackers to upload arbitrary files without authentication via upload.php. This affects Joomla! installations with the TinyBrowser plugin enabled before version 1.5.13. Attackers can upload malicious files including webshells to gain control of the server.
💻 Affected Systems
- Joomla! with TinyBrowser plugin
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete server compromise via remote code execution, data theft, defacement, and lateral movement within the network.
Likely Case
Webshell upload leading to website defacement, data exfiltration, and backdoor persistence on the server.
If Mitigated
Limited impact if file uploads are restricted, web application firewall blocks malicious uploads, and proper file permissions are enforced.
🎯 Exploit Status
Simple HTTP POST request to upload.php with malicious file. Multiple public exploits available since 2011.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Joomla! 1.5.13 and later
Vendor Advisory: https://developer.joomla.org/security-centre/
Restart Required: No
Instructions:
1. Update Joomla! to version 1.5.13 or later. 2. Remove or disable the TinyBrowser plugin if not needed. 3. Apply all security patches for Joomla! core.
🔧 Temporary Workarounds
Disable TinyBrowser plugin
allRemove or disable the vulnerable TinyBrowser plugin from Joomla! installation
Navigate to Joomla! administrator panel > Extensions > Plugin Manager > Disable TinyBrowser plugin
Or delete /plugins/editors/tinymce/tinybrowser directory
Block upload.php access
allUse web server configuration to block access to the vulnerable upload.php file
Apache: Add 'Deny from all' to .htaccess in tinybrowser directory
Nginx: location ~ /tinybrowser/upload\.php { deny all; }
🧯 If You Can't Patch
- Implement strict file upload validation and filtering at web application firewall level
- Restrict file permissions on upload directories and monitor for suspicious file creation
🔍 How to Verify
Check if Vulnerable:
Check if /plugins/editors/tinymce/tinybrowser/upload.php exists and Joomla! version is below 1.5.13Check Version:
Check Joomla! administrator panel or examine includes/version.php fileVerify Fix Applied:
Confirm Joomla! version is 1.5.13+ and upload.php file is removed or inaccessible📡 Detection & Monitoring
Log Indicators:
- HTTP POST requests to /tinybrowser/upload.php
- File uploads with unusual extensions (.php, .phtml, .jsp)
- Large number of failed upload attempts
Network Indicators:
- HTTP traffic to upload.php with file upload patterns
- Outbound connections from web server after file upload
SIEM Query:
web.url:*tinybrowser*upload.php AND http.method:POST🔗 References
- https://vulmon.com/vulnerabilitydetails?qid=CVE-2011-4908
- https://www.exploit-db.com/exploits/9926
- https://www.openwall.com/lists/oss-security/2011/12/25/7
- https://vulmon.com/vulnerabilitydetails?qid=CVE-2011-4908
- https://www.exploit-db.com/exploits/9926
- https://www.openwall.com/lists/oss-security/2011/12/25/7
