CVE-2024-0536
📋 TL;DR
A critical stack-based buffer overflow vulnerability in Tenda W9 routers allows remote attackers to execute arbitrary code by manipulating the ssidIndex parameter in the setWrlAccessList function of the httpd component. This affects Tenda W9 router version 1.0.0.7(4456) and potentially other versions. Attackers can exploit this without authentication to gain full control of affected devices.
💻 Affected Systems
- Tenda W9
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, persistent backdoor installation, network traffic interception, and lateral movement to other devices on the network.
Likely Case
Remote code execution allowing attackers to modify router settings, intercept network traffic, install malware, or use the device as part of a botnet.
If Mitigated
If properly segmented and monitored, impact limited to the router itself with potential for network traffic monitoring but prevented lateral movement.
🎯 Exploit Status
Exploit code has been publicly disclosed on GitHub. The vulnerability requires no authentication and has straightforward exploitation.
🛠️ 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 web interface 3. Reboot router after update 4. Verify version is no longer 1.0.0.7(4456)
🔧 Temporary Workarounds
Disable remote management
allDisable web interface access from WAN/internet to prevent remote exploitation
Login to router admin panel -> Advanced Settings -> Remote Management -> Disable
Network segmentation
allIsolate router management interface to separate VLAN or restrict access
🧯 If You Can't Patch
- Replace affected Tenda W9 routers with different models from vendors with better security response
- Implement strict network firewall rules to block all inbound traffic to router management interface (typically ports 80/443)
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via web interface: Login -> System Status -> Firmware Version. If version is 1.0.0.7(4456), device is vulnerable.Check Version:
Check via web interface or attempt to connect to router IP and review HTTP headers for version informationVerify Fix Applied:
Verify firmware version is no longer 1.0.0.7(4456) after any update. No specific patch version available from vendor.📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP POST requests to setWrlAccessList endpoint
- Multiple failed exploitation attempts with malformed ssidIndex parameters
- Unexpected router reboots or configuration changes
Network Indicators:
- Unusual outbound connections from router IP
- Traffic patterns suggesting router compromise (C2 communications)
- Port scanning originating from router
SIEM Query:
source="router_logs" AND (uri="*setWrlAccessList*" OR method="POST" AND uri_contains="access") AND (param_contains="ssidIndex" AND length(param_value)>normal)