CVE-2024-24157
📋 TL;DR
This Cross-Site Scripting (XSS) vulnerability in Gnuboard g6 allows attackers to inject malicious scripts into web pages viewed by other users. It affects users of Gnuboard g6 content management system who visit compromised pages. The vulnerability is in board.py and can be exploited through user input.
💻 Affected Systems
- Gnuboard g6
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers could steal session cookies, perform actions as authenticated users, deface websites, or redirect users to malicious sites, potentially leading to account compromise and data theft.
Likely Case
Attackers inject malicious scripts to steal session cookies or user credentials, potentially compromising user accounts on the affected Gnuboard installation.
If Mitigated
With proper input validation and output encoding, the impact is limited to script execution in user's browser context only, preventing data exfiltration or privilege escalation.
🎯 Exploit Status
XSS vulnerabilities typically have low exploitation complexity and can be exploited by unauthenticated attackers if the vulnerable endpoint is accessible.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after commit c2cc1f5069e00491ea48618d957332d90f6d40e4
Vendor Advisory: https://github.com/gnuboard/g6/issues/314
Restart Required: No
Instructions:
1. Update to the latest Gnuboard g6 version. 2. Replace board.py with the patched version from the repository. 3. Clear any cached files or templates.
🔧 Temporary Workarounds
Input Validation Filter
allImplement server-side input validation to sanitize user input before processing in board.py
# Add input sanitization in board.py before processing user data
# Example: htmlspecialchars() or similar escaping functions
Content Security Policy
allImplement CSP headers to restrict script execution sources
# Add to web server configuration or application headers:
Content-Security-Policy: default-src 'self'; script-src 'self'
🧯 If You Can't Patch
- Implement web application firewall (WAF) rules to block XSS payloads
- Disable or restrict access to the vulnerable board.py functionality if not essential
🔍 How to Verify
Check if Vulnerable:
Check if your Gnuboard g6 version includes commit c2cc1f5069e00491ea48618d957332d90f6d40e4 or earlier in board.pyCheck Version:
git log --oneline board.py | head -20Verify Fix Applied:
Verify that board.py has been updated to a version after the vulnerable commit and test XSS payloads are properly sanitized📡 Detection & Monitoring
Log Indicators:
- Unusual POST/GET requests to board.py with script tags or JavaScript code
- Multiple failed attempts with encoded payloads
Network Indicators:
- HTTP requests containing <script>, javascript:, or encoded XSS payloads to board endpoints
SIEM Query:
source="web_logs" AND (uri="*board.py*" AND (content="*<script>*" OR content="*javascript:*" OR content="*onload=*"))