CVE-2024-41281
📋 TL;DR
The Linksys WRT54G router version 4.21.5 contains a stack overflow vulnerability in the get_merge_mac function. This allows attackers to execute arbitrary code or cause denial of service by sending specially crafted requests. Only users of this specific router model and firmware version are affected.
💻 Affected Systems
- Linksys WRT54G
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to full device compromise, persistent backdoor installation, and lateral movement to connected networks.
Likely Case
Denial of service causing router crashes and network disruption, potentially requiring physical reset.
If Mitigated
Limited impact if network segmentation isolates the router and external access is restricted.
🎯 Exploit Status
Public proof-of-concept exists in GitHub repository. Exploitation requires sending crafted packets to the vulnerable function.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: N/A
Vendor Advisory: N/A
Restart Required: No
Instructions:
No official patch available from Linksys as this is an end-of-life product. Consider upgrading to supported hardware.
🔧 Temporary Workarounds
Network Segmentation
allIsolate the vulnerable router from critical networks and restrict external access.
Access Control Lists
linuxImplement firewall rules to restrict access to the router's management interface.
iptables -A INPUT -p tcp --dport 80 -s trusted_network -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
🧯 If You Can't Patch
- Replace with modern, supported router hardware that receives security updates
- Implement network monitoring to detect exploitation attempts and anomalous traffic patterns
🔍 How to Verify
Check if Vulnerable:
Check router web interface or use command 'cat /proc/version' via SSH/Telnet to confirm model WRT54G and firmware 4.21.5Check Version:
cat /proc/version || check web interface at http://router_ipVerify Fix Applied:
Verify router has been replaced or isolated. No patch exists to verify.📡 Detection & Monitoring
Log Indicators:
- Router crash/reboot logs
- Unusual traffic patterns to router management interface
- Failed authentication attempts followed by crash
Network Indicators:
- Abnormal packets targeting router ports
- Traffic spikes to router from untrusted sources
- Router becoming unresponsive
SIEM Query:
source="router_logs" AND (event="crash" OR event="reboot") OR dest_ip="router_ip" AND (protocol="tcp" AND (port=80 OR port=443) AND packet_size>threshold)