CVE-2024-39954
📋 TL;DR
This CVE describes a Server-Side Request Forgery (SSRF) vulnerability in the eventmesh-runtime module's WebhookUtil.java component. Attackers can exploit this to make the server send requests to internal systems, potentially accessing or modifying sensitive resources. Any system running vulnerable versions of Apache EventMesh with webhook functionality enabled is affected.
💻 Affected Systems
- Apache EventMesh
📦 What is this software?
Eventmesh by Apache
⚠️ Risk & Real-World Impact
Worst Case
Attacker gains access to internal cloud metadata services, accesses internal APIs, or performs port scanning of internal networks leading to lateral movement and data exfiltration.
Likely Case
Attacker accesses internal HTTP services, retrieves sensitive information from internal endpoints, or performs limited internal network reconnaissance.
If Mitigated
Requests are limited to specific allowed domains, preventing access to internal resources and metadata services.
🎯 Exploit Status
Exploitation requires the ability to trigger webhook functionality with attacker-controlled URLs.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.12.0 or master branch
Vendor Advisory: https://lists.apache.org/thread/v6c96zygqx8xc2k3n2d59mgnm5txhkon
Restart Required: No
Instructions:
1. Download Apache EventMesh version 1.12.0 or later from official sources. 2. Replace the vulnerable eventmesh-runtime module. 3. Verify the WebhookUtil.java file contains SSRF protections.
🔧 Temporary Workarounds
Network Segmentation
linuxRestrict outbound network access from the EventMesh server to only necessary external endpoints.
iptables -A OUTPUT -p tcp --dport 80 -j DROP
iptables -A OUTPUT -p tcp --dport 443 -j DROP
Input Validation
allImplement URL validation to reject requests to internal IP ranges and localhost.
🧯 If You Can't Patch
- Disable webhook functionality entirely if not required
- Implement strict egress filtering to block requests to internal IP ranges (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16, 127.0.0.0/8)
🔍 How to Verify
Check if Vulnerable:
Check if EventMesh version is below 1.12.0 and webhook functionality is enabled.Check Version:
java -jar eventmesh-runtime.jar --versionVerify Fix Applied:
Verify the installed version is 1.12.0 or higher and test webhook functionality with internal URLs to confirm they are blocked.📡 Detection & Monitoring
Log Indicators:
- Unusual outbound HTTP requests from EventMesh to internal IP addresses
- Webhook requests containing localhost or internal network addresses
Network Indicators:
- EventMesh server making HTTP requests to internal services or cloud metadata endpoints
SIEM Query:
source="eventmesh" AND (url CONTAINS "169.254.169.254" OR url CONTAINS "localhost" OR url CONTAINS "127.0.0.1" OR url CONTAINS "10." OR url CONTAINS "192.168." OR url CONTAINS "172.")