CVE-2024-42699
📋 TL;DR
This stored cross-site scripting (XSS) vulnerability in Alkacon OpenCMS 17.0 allows remote attackers to inject malicious JavaScript payloads via the image title field when creating or modifying articles. When exploited, this can lead to session hijacking, credential theft, or website defacement. Users of OpenCMS 17.0 who allow article creation/modification are affected.
💻 Affected Systems
- Alkacon OpenCMS
📦 What is this software?
Opencms by Alkacon
⚠️ Risk & Real-World Impact
Worst Case
Complete account takeover, administrative privilege escalation, data exfiltration, and persistent website compromise affecting all users who view malicious articles.
Likely Case
Session hijacking for authenticated users, credential theft via phishing, and website defacement through injected content.
If Mitigated
Limited impact with proper content sanitization, CSP headers, and user awareness training.
🎯 Exploit Status
Exploitation requires article creation/modification access. The GitHub reference contains detailed proof-of-concept documentation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: Not available
Restart Required: No
Instructions:
No official patch available. Monitor Alkacon OpenCMS security advisories for updates. Consider upgrading to newer versions if available.
🔧 Temporary Workarounds
Input Validation and Sanitization
allImplement server-side validation and HTML encoding for all image title inputs in article creation/modification functions.
Content Security Policy (CSP)
allImplement strict CSP headers to prevent execution of inline JavaScript and restrict script sources.
Content-Security-Policy: default-src 'self'; script-src 'self'
🧯 If You Can't Patch
- Disable article creation/modification for untrusted users
- Implement web application firewall (WAF) rules to block XSS payloads in image title fields
🔍 How to Verify
Check if Vulnerable:
Test by creating/modifying an article with JavaScript payload in image title field (e.g., <script>alert('XSS')</script>) and check if it executes when viewing the article.Check Version:
Check OpenCMS version in administration interface or configuration files.Verify Fix Applied:
After implementing workarounds, test with same payload to confirm it's properly sanitized or blocked.📡 Detection & Monitoring
Log Indicators:
- Unusual article modifications, suspicious image title entries containing script tags or JavaScript patterns
Network Indicators:
- HTTP requests with JavaScript payloads in image title parameters
SIEM Query:
web_logs WHERE url_path CONTAINS '/opencms/' AND (request_body CONTAINS '<script' OR request_body CONTAINS 'javascript:')