CVE-2023-34061
📋 TL;DR
This vulnerability allows unauthenticated attackers to trigger route pruning in Cloud Foundry's gorouter, causing denial of service by degrading service availability. It affects Cloud Foundry deployments using routing release versions v0.163.0 through v0.283.0.
💻 Affected Systems
- Cloud Foundry routing release (gorouter)
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete service disruption where legitimate traffic cannot reach applications, effectively taking down the Cloud Foundry deployment.
Likely Case
Degraded performance and intermittent service outages as routes are pruned and need to be re-registered.
If Mitigated
Minimal impact if proper rate limiting and monitoring are in place to detect and block pruning attacks.
🎯 Exploit Status
Attack requires no authentication and can be performed with simple HTTP requests to trigger route pruning.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v0.284.0 and later
Vendor Advisory: https://www.cloudfoundry.org/blog/cve-2023-34061-gorouter-route-pruning/
Restart Required: Yes
Instructions:
1. Update Cloud Foundry routing release to v0.284.0 or later. 2. Deploy the updated routing release. 3. Restart gorouter instances. 4. Verify the fix is applied.
🔧 Temporary Workarounds
Rate limiting
allImplement rate limiting on gorouter endpoints to prevent excessive pruning requests
Network segmentation
allRestrict access to gorouter management endpoints to trusted networks only
🧯 If You Can't Patch
- Implement strict network access controls to limit who can reach gorouter endpoints
- Deploy additional monitoring and alerting for unusual route pruning activity
🔍 How to Verify
Check if Vulnerable:
Check the routing release version in your Cloud Foundry deployment. If between v0.163.0 and v0.283.0 inclusive, you are vulnerable.Check Version:
cf curl /routing/v1/router_groupsVerify Fix Applied:
Confirm routing release version is v0.284.0 or later and monitor for abnormal route pruning events.📡 Detection & Monitoring
Log Indicators:
- Unusual frequency of route pruning events
- Multiple pruning requests from single IP addresses
- Error logs related to route registration failures
Network Indicators:
- High volume of requests to gorouter pruning endpoints
- Requests to /routes/prune endpoint from untrusted sources
SIEM Query:
source="gorouter" AND ("prune" OR "route registration failed")