CVE-2024-0541
📋 TL;DR
A critical stack-based buffer overflow vulnerability exists in Tenda W9 routers running firmware version 1.0.0.7(4456). Attackers can remotely exploit this vulnerability by sending specially crafted HTTP requests to the httpd component's formAddSysLogRule function, potentially allowing arbitrary code execution. This affects all users of vulnerable Tenda W9 routers exposed to network access.
💻 Affected Systems
- Tenda W9
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote attackers gain full control of the router, enabling them to intercept network traffic, install persistent malware, pivot to internal networks, or brick the device.
Likely Case
Remote code execution leading to router compromise, enabling traffic interception, DNS hijacking, or participation in botnets.
If Mitigated
If properly segmented and firewalled, impact limited to router compromise without lateral movement to other systems.
🎯 Exploit Status
Exploit code is publicly available on GitHub. The vulnerability requires no authentication and has a straightforward exploitation path.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: None available - vendor did not respond to disclosure
Restart Required: Yes
Instructions:
1. Check Tenda website for firmware updates. 2. If update available, download and install via router admin interface. 3. Reboot router after installation. 4. Verify firmware version is no longer 1.0.0.7(4456).
🔧 Temporary Workarounds
Network Segmentation
allIsolate Tenda W9 routers from untrusted networks and restrict access to management interface.
Access Control Lists
linuxImplement firewall rules to restrict HTTP access to router 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 vulnerable Tenda W9 routers with different models or brands that receive security updates
- Implement strict network segmentation to isolate vulnerable routers from critical systems
🔍 How to Verify
Check if Vulnerable:
Access router web interface, navigate to System Status or About page, check firmware version matches 1.0.0.7(4456).Check Version:
curl -s http://router-ip/ | grep -i firmware || ssh admin@router-ip 'cat /etc/version'Verify Fix Applied:
After firmware update, verify version is no longer 1.0.0.7(4456). Test by attempting to access formAddSysLogRule endpoint with test payload.📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP POST requests to formAddSysLogRule endpoint
- Large payloads in HTTP requests to router
- Router crash/restart logs
Network Indicators:
- HTTP POST requests with oversized sysRulenEn parameter to router port 80
- Unusual outbound connections from router after exploitation
SIEM Query:
source="router_logs" AND (url="*formAddSysLogRule*" AND content_length>1000) OR (process="httpd" AND event="crash")