CVE-2023-38434
📋 TL;DR
CVE-2023-38434 is a double-free vulnerability in xHTTP's close_connection function that can be triggered via malformed HTTP request methods. This allows attackers to potentially execute arbitrary code or cause denial of service. Anyone running vulnerable versions of xHTTP is affected.
💻 Affected Systems
- xHTTP
📦 What is this software?
Xhttp by Xhttp Project
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise
Likely Case
Denial of service causing application crashes
If Mitigated
Limited impact with proper memory protection mechanisms
🎯 Exploit Status
Proof of concept available in GitHub issues; exploitation requires sending malformed HTTP requests
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in commits after 72f812d
Vendor Advisory: https://github.com/cozis/xHTTP/issues/1
Restart Required: Yes
Instructions:
1. Update to latest xHTTP version
2. Rebuild from source if using custom builds
3. Restart xHTTP service
🔧 Temporary Workarounds
HTTP Request Filtering
linuxBlock malformed HTTP requests at network perimeter
iptables -A INPUT -p tcp --dport 80 -m string --string "malformed_method" --algo bm -j DROP
Web Application Firewall
allConfigure WAF to reject invalid HTTP methods
🧯 If You Can't Patch
- Isolate xHTTP instances behind reverse proxies with request validation
- Implement network segmentation to limit blast radius
🔍 How to Verify
Check if Vulnerable:
Check xHTTP version or commit hash against vulnerable rangeCheck Version:
xhttp --version or check source commit hashVerify Fix Applied:
Test with malformed HTTP requests and monitor for crashes📡 Detection & Monitoring
Log Indicators:
- Multiple connection resets
- Memory allocation errors
- Unexpected process termination
Network Indicators:
- Malformed HTTP requests with unusual methods
- Repeated connection attempts
SIEM Query:
source="xhttp" AND (event="crash" OR event="segfault")