CVE-2024-8736
📋 TL;DR
This CSRF vulnerability in lollms-webui allows attackers to cause denial of service by exploiting file upload endpoints. Attackers can append extra characters to multipart boundaries, forcing the server to exhaust resources parsing each byte. All users running the vulnerable version are affected.
💻 Affected Systems
- parisneo/lollms-webui
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete service unavailability with server resource exhaustion, requiring manual intervention to restore functionality.
Likely Case
Temporary service degradation or downtime affecting file upload functionality and potentially other services on the same server.
If Mitigated
Minimal impact with proper CSRF protection and boundary validation in place.
🎯 Exploit Status
Exploitation requires CSRF but is straightforward once the attack vector is established.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check latest release after V12
Vendor Advisory: https://huntr.com/bounties/935dbc03-1b43-4dbb-b6cd-1aa95a789d4f
Restart Required: Yes
Instructions:
1. Check for updated version on GitHub. 2. Update to patched version. 3. Restart the lollms-webui service.
🔧 Temporary Workarounds
Disable vulnerable endpoints
allTemporarily disable /upload_avatar, /upload_app, and /upload_logo endpoints
Modify application configuration to disable these routes
Implement strict boundary validation
allAdd server-side validation for multipart boundary length and format
Implement boundary length limits in file upload handlers
🧯 If You Can't Patch
- Implement WAF rules to block requests with abnormal boundary lengths
- Rate limit file upload endpoints to prevent resource exhaustion
🔍 How to Verify
Check if Vulnerable:
Check if running lollms-webui V12 and test file upload endpoints with malformed boundariesCheck Version:
Check lollms-webui version in application interface or configuration filesVerify Fix Applied:
Test that malformed boundary requests are rejected and no longer cause resource exhaustion📡 Detection & Monitoring
Log Indicators:
- Multiple failed file upload attempts with abnormal boundary lengths
- High CPU/memory usage spikes during upload attempts
Network Indicators:
- Repeated POST requests to /upload_* endpoints with unusual boundary parameters
SIEM Query:
source="web_server" AND (uri_path="/upload_avatar" OR uri_path="/upload_app" OR uri_path="/upload_logo") AND boundary_length>100