CVE-2022-26127
📋 TL;DR
CVE-2022-26127 is a buffer overflow vulnerability in FRRouting's Babel routing protocol daemon that allows remote attackers to execute arbitrary code or cause denial of service. The vulnerability affects FRRouting installations with Babel protocol enabled, particularly network devices and servers running affected versions. Attackers can exploit this by sending specially crafted Babel packets to vulnerable systems.
💻 Affected Systems
- FRRouting
📦 What is this software?
Frrouting by Frrouting
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, allowing attackers to install malware, pivot to other systems, or disrupt network operations.
Likely Case
Denial of service causing routing instability, network outages, or system crashes affecting network connectivity.
If Mitigated
Limited impact if proper network segmentation, firewalls, and access controls prevent unauthorized access to Babel ports.
🎯 Exploit Status
Exploitation requires sending crafted packets to the Babel daemon port (typically UDP 6696). No authentication is required if network access is available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: FRRouting 8.2 and later
Vendor Advisory: https://github.com/FRRouting/frr/issues/10487
Restart Required: Yes
Instructions:
1. Update FRRouting to version 8.2 or later. 2. For Debian/Ubuntu: apt update && apt install frr. 3. Restart FRRouting service: systemctl restart frr. 4. Verify Babel daemon is running correctly.
🔧 Temporary Workarounds
Disable Babel Protocol
linuxTemporarily disable Babel routing protocol if not essential for network operations
systemctl stop babeld
frr-reload.py --disable babeld
Network Access Control
linuxRestrict access to Babel port (UDP 6696) using firewall rules
iptables -A INPUT -p udp --dport 6696 -j DROP
ufw deny 6696/udp
🧯 If You Can't Patch
- Implement strict network segmentation to isolate Babel traffic to trusted networks only
- Deploy intrusion detection systems to monitor for anomalous Babel packet patterns
🔍 How to Verify
Check if Vulnerable:
Check FRRouting version: frr --version. If version is 8.1.0 or earlier and Babel is enabled, system is vulnerable.Check Version:
frr --versionVerify Fix Applied:
Verify FRRouting version is 8.2 or later: frr --version. Check Babel daemon status: systemctl status babeld.📡 Detection & Monitoring
Log Indicators:
- Babel daemon crash logs in /var/log/frr/babeld.log
- System logs showing segmentation faults in babeld process
Network Indicators:
- Unusually large Babel packets to UDP port 6696
- Multiple malformed Babel protocol packets from single source
SIEM Query:
source="babeld.log" AND ("segmentation fault" OR "buffer overflow" OR "crash")