CVE-2023-49089
📋 TL;DR
This vulnerability allows authenticated Umbraco backoffice users with package creation permissions to perform path traversal attacks, enabling them to write files outside intended directories. It affects Umbraco CMS installations from version 8.0.0 up to but not including 8.18.10, 10.8.1, and 12.3.0. Attackers could potentially write malicious files to sensitive locations on the server.
💻 Affected Systems
- Umbraco CMS
📦 What is this software?
Umbraco Cms by Umbraco
Umbraco Cms by Umbraco
Umbraco Cms by Umbraco
⚠️ Risk & Real-World Impact
Worst Case
An attacker with backoffice access could write arbitrary files to critical system directories, potentially leading to remote code execution, data theft, or complete system compromise.
Likely Case
Privileged backoffice users could write configuration files or scripts to unauthorized locations, enabling privilege escalation or persistence mechanisms.
If Mitigated
With proper access controls and monitoring, impact is limited to unauthorized file writes within the application's directory structure.
🎯 Exploit Status
Exploitation requires authenticated access with specific permissions; path traversal techniques are well-documented.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 8.18.10, 10.8.1, or 12.3.0
Vendor Advisory: https://github.com/umbraco/Umbraco-CMS/security/advisories/GHSA-6324-52pr-h4p5
Restart Required: Yes
Instructions:
1. Identify your Umbraco version. 2. Upgrade to 8.18.10 (for v8), 10.8.1 (for v10), or 12.3.0 (for v12). 3. Restart the application. 4. Verify the patch is applied.
🔧 Temporary Workarounds
Restrict Package Creation Permissions
allTemporarily remove package creation permissions from all backoffice users except essential administrators.
Navigate to Users section in Umbraco backoffice
Edit user permissions to remove 'Packages' section access
File System Monitoring
allImplement monitoring on directories outside the Umbraco application path for unauthorized file writes.
Configure file integrity monitoring on critical directories
Set up alerts for file creation outside /umbraco/ directory
🧯 If You Can't Patch
- Implement strict principle of least privilege for backoffice users
- Deploy web application firewall with path traversal protection rules
🔍 How to Verify
Check if Vulnerable:
Check Umbraco version in /umbraco/UmbracoApi/Update/GetUpgradeStatus or view version in backoffice dashboard.Check Version:
curl -s http://your-umbraco-site/umbraco/UmbracoApi/Update/GetUpgradeStatus | grep -o '"currentVersion":"[^"]*"'Verify Fix Applied:
Confirm version is 8.18.10, 10.8.1, or 12.3.0 or higher in backoffice or via version API.📡 Detection & Monitoring
Log Indicators:
- Unusual file write operations in Umbraco logs
- Package creation events followed by file system writes
- Path traversal patterns in request logs
Network Indicators:
- HTTP requests with '../' sequences in package-related endpoints
- Unusual file upload patterns to package endpoints
SIEM Query:
source="umbraco.logs" AND ("CreatePackage" OR "SavePackage") AND ("..\\" OR "../" OR "%2e%2e")