CVE-2025-63652
📋 TL;DR
A use-after-free vulnerability in Monkey web server's HTTP request handling allows attackers to crash the server by sending a specially crafted HTTP request. This affects all systems running vulnerable versions of Monkey web server, potentially causing service disruption.
💻 Affected Systems
- Monkey web server
📦 What is this software?
Monkey by Monkey Project
⚠️ Risk & Real-World Impact
Worst Case
Complete denial of service with server crash and potential memory corruption leading to remote code execution in specific conditions.
Likely Case
Server crash and service disruption requiring manual restart, causing downtime for hosted applications.
If Mitigated
Limited impact with proper network segmentation and monitoring allowing quick detection and recovery.
🎯 Exploit Status
Exploitation requires sending a crafted HTTP request to trigger the use-after-free condition.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after commit f37e984
Vendor Advisory: https://github.com/monkey/monkey/issues/426
Restart Required: Yes
Instructions:
1. Update Monkey web server to latest version. 2. Check GitHub for patched commits. 3. Restart the Monkey service after update.
🔧 Temporary Workarounds
Network filtering
allBlock or filter suspicious HTTP requests at network perimeter
Load balancer protection
allConfigure load balancer to drop malformed HTTP requests
🧯 If You Can't Patch
- Implement strict network segmentation to limit access to Monkey servers
- Deploy WAF with rules to detect and block exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check Monkey version or commit hash against vulnerable range (up to f37e984)Check Version:
monkey --version or check commit hash in sourceVerify Fix Applied:
Verify updated to version after f37e984 commit and test with known exploit attempts📡 Detection & Monitoring
Log Indicators:
- Server crash logs
- Abnormal termination of Monkey process
- Memory error messages in system logs
Network Indicators:
- Malformed HTTP requests causing server crashes
- Repeated connection attempts to trigger vulnerability
SIEM Query:
source="monkey.log" AND ("crash" OR "segmentation fault" OR "use-after-free")