CVE-2024-37658
📋 TL;DR
An open redirect vulnerability in gnuboard5 v5.5.16 allows attackers to redirect users to malicious websites via the bbs/member_confirm.php endpoint. This can lead to phishing attacks, credential theft, or malware distribution. All users running the vulnerable version are affected.
💻 Affected Systems
- gnuboard5
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Users are redirected to sophisticated phishing sites that steal credentials, session tokens, or install malware, leading to account compromise and data breaches.
Likely Case
Attackers redirect users to phishing pages to harvest login credentials or distribute low-level malware.
If Mitigated
With proper input validation and URL whitelisting, the redirect is blocked or sanitized, preventing exploitation.
🎯 Exploit Status
Exploitation requires crafting a malicious URL parameter; no authentication needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v5.5.17 or later
Vendor Advisory: https://github.com/gnuboard/gnuboard5/issues/319
Restart Required: No
Instructions:
1. Download the latest gnuboard5 version from the official repository. 2. Replace the vulnerable bbs/member_confirm.php file with the patched version. 3. Verify the fix by testing redirect functionality.
🔧 Temporary Workarounds
Input Validation Workaround
allAdd server-side validation to sanitize or block malicious redirect URLs in bbs/member_confirm.php.
Edit bbs/member_confirm.php to validate the 'url' parameter against a whitelist of allowed domains.
🧯 If You Can't Patch
- Implement a web application firewall (WAF) rule to block requests with suspicious redirect parameters.
- Disable or restrict access to the bbs/member_confirm.php endpoint if not needed.
🔍 How to Verify
Check if Vulnerable:
Test by accessing bbs/member_confirm.php with a malicious 'url' parameter (e.g., ?url=http://evil.com) and check if it redirects.Check Version:
Check the gnuboard5 version in the admin panel or via the software's version file.Verify Fix Applied:
After patching, test the same malicious parameter; it should not redirect or should sanitize the URL.📡 Detection & Monitoring
Log Indicators:
- Log entries showing redirects to external domains from bbs/member_confirm.php with suspicious parameters.
Network Indicators:
- HTTP 302 redirect responses from the vulnerable endpoint to untrusted domains.
SIEM Query:
source="web_logs" AND uri="/bbs/member_confirm.php" AND status=302 AND url_domain NOT IN ("trusted.com")