CVE-2023-4159
📋 TL;DR
This vulnerability allows attackers to upload malicious files to Omeka-S web applications, potentially leading to remote code execution. It affects all Omeka-S installations prior to version 4.0.3. The issue stems from insufficient file type validation in the upload functionality.
💻 Affected Systems
- Omeka-S
📦 What is this software?
Omeka S by Omeka
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, and lateral movement within the network.
Likely Case
Webshell deployment allowing persistent access, data exfiltration, and further exploitation of the server environment.
If Mitigated
File uploads blocked or restricted to safe types only, preventing malicious file execution.
🎯 Exploit Status
Exploitation requires authenticated access but is straightforward once authenticated. Public proof-of-concept exists in the huntr.dev bounty report.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4.0.3
Vendor Advisory: https://github.com/omeka/omeka-s/commit/2a7fb26452167c8a1d95f207ae5328c6b1b0fcf8
Restart Required: Yes
Instructions:
1. Backup your Omeka-S installation and database. 2. Download Omeka-S version 4.0.3 or later from the official repository. 3. Replace the existing installation with the patched version. 4. Restart your web server. 5. Verify the patch is applied by checking the version.
🔧 Temporary Workarounds
Disable File Uploads
allTemporarily disable all file upload functionality in Omeka-S until patching can be completed.
Modify Omeka-S configuration to remove file upload permissions or disable relevant modules
Web Application Firewall Rules
allImplement WAF rules to block malicious file uploads based on file extensions and content types.
Add WAF rules to block uploads of executable files (php, asp, jsp, etc.) and suspicious content types
🧯 If You Can't Patch
- Implement strict file upload validation at the web server level (e.g., mod_security rules for Apache, nginx restrictions)
- Deploy network segmentation to isolate Omeka-S instances and limit potential lateral movement
🔍 How to Verify
Check if Vulnerable:
Check your Omeka-S version. If it's below 4.0.3, you are vulnerable. Also check if file upload functionality exists and accepts dangerous file types.Check Version:
Check the version.php file in your Omeka-S installation or view the admin dashboard version information.Verify Fix Applied:
After updating to 4.0.3 or later, attempt to upload a file with dangerous extensions (like .php, .asp). The upload should be rejected with proper validation errors.📡 Detection & Monitoring
Log Indicators:
- Multiple failed upload attempts with suspicious file extensions
- Successful uploads of executable files to upload directories
- Web server logs showing execution of uploaded files
Network Indicators:
- Unusual outbound connections from the Omeka-S server
- Traffic patterns indicating data exfiltration
SIEM Query:
source="web_server_logs" AND (file_extension="php" OR file_extension="asp" OR file_extension="jsp") AND action="upload" AND status="200"