CVE-2023-41361
📋 TL;DR
CVE-2023-41361 is a buffer overflow vulnerability in FRRouting's BGP daemon (bgpd) that occurs when processing BGP OPEN messages with overly large software version strings. Attackers can exploit this to execute arbitrary code or crash the bgpd process, potentially compromising routing infrastructure. Organizations running FRRouting with BGP enabled are affected.
💻 Affected Systems
- FRRouting FRR
📦 What is this software?
Frrouting by Frrouting
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete compromise of the routing daemon, enabling attackers to manipulate routing tables, intercept traffic, or pivot to other network segments.
Likely Case
Denial of service through bgpd process crash, disrupting BGP peering and causing network outages until service is restored.
If Mitigated
Limited impact if proper network segmentation and BGP session filtering are in place, potentially containing the attack to isolated segments.
🎯 Exploit Status
Exploitation requires sending a malicious BGP OPEN message, which can be done by any BGP peer or attacker who can establish a BGP session.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: FRR 9.0.1 or later
Vendor Advisory: https://github.com/FRRouting/frr/pull/14241
Restart Required: Yes
Instructions:
1. Update FRR to version 9.0.1 or later using your distribution's package manager. 2. Restart the bgpd service: 'systemctl restart frr' or 'service frr restart'. 3. Verify the patch is applied by checking the FRR version.
🔧 Temporary Workarounds
BGP Session Filtering
linuxImplement strict BGP session filtering to only allow connections from trusted peers using access lists or firewall rules.
ip access-list standard TRUSTED_PEERS
permit host <trusted-peer-ip>
router bgp <as-number>
neighbor <trusted-peer-ip> remote-as <peer-as>
neighbor <trusted-peer-ip> prefix-list TRUSTED_PEERS in
🧯 If You Can't Patch
- Implement strict network segmentation to isolate BGP-speaking devices from untrusted networks.
- Deploy intrusion detection/prevention systems (IDS/IPS) to monitor for anomalous BGP traffic patterns.
🔍 How to Verify
Check if Vulnerable:
Check FRR version: 'frr --version' or 'vtysh -c 'show version''. If version is 9.0, the system is vulnerable.Check Version:
frr --versionVerify Fix Applied:
After patching, verify the version is 9.0.1 or later using 'frr --version'. Also monitor bgpd logs for stability.📡 Detection & Monitoring
Log Indicators:
- bgpd process crashes in system logs
- Unusual BGP session resets or failures in FRR logs
Network Indicators:
- Abnormal BGP OPEN messages with large payloads
- Sudden BGP session drops from specific peers
SIEM Query:
source="frr.log" AND "bgpd" AND ("crash" OR "segmentation fault" OR "buffer overflow")