CVE-2023-50020
📋 TL;DR
This vulnerability in open5gs v2.6.6 allows attackers to crash the AMF (Access and Mobility Management Function) component by exploiting SIGPIPE signals. This affects systems running vulnerable versions of open5gs, potentially causing service disruption in 5G core networks.
💻 Affected Systems
- open5gs
📦 What is this software?
Open5gs by Open5gs
⚠️ Risk & Real-World Impact
Worst Case
Complete denial of service for 5G core network, disrupting mobile connectivity for all users served by the affected AMF.
Likely Case
Service disruption requiring AMF restart, causing temporary connectivity loss for mobile users.
If Mitigated
Minimal impact with proper monitoring and automated recovery mechanisms in place.
🎯 Exploit Status
SIGPIPE exploitation typically requires network access to the AMF service.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in commit 1aba814938e3a1b2eec7014bf6ce132d34622e08
Vendor Advisory: https://github.com/open5gs/open5gs/issues/2734
Restart Required: Yes
Instructions:
1. Update open5gs to latest version or apply commit 1aba814. 2. Recompile and reinstall open5gs. 3. Restart AMF service.
🔧 Temporary Workarounds
SIGPIPE Signal Handling
linuxConfigure system to ignore SIGPIPE signals or handle them gracefully
ulimit -c unlimited
trap '' SIGPIPE
🧯 If You Can't Patch
- Implement network segmentation to restrict access to AMF service
- Deploy redundant AMF instances with load balancing to maintain service during crashes
🔍 How to Verify
Check if Vulnerable:
Check open5gs version and verify if commit 1aba814 is appliedCheck Version:
open5gs-amfd --versionVerify Fix Applied:
Verify AMF service remains stable during network stress testing📡 Detection & Monitoring
Log Indicators:
- AMF process crashes
- SIGPIPE errors in system logs
- Service restart messages
Network Indicators:
- Unusual TCP connection patterns to AMF port
- Repeated connection attempts
SIEM Query:
process:open5gs-amfd AND (event:crash OR signal:SIGPIPE)