CVE-2023-51094
📋 TL;DR
Tenda M3 routers running firmware version 1.0.0.12(4856) contain a command injection vulnerability in the TendaTelnet function. This allows remote attackers to execute arbitrary commands with root privileges. All users of affected Tenda M3 routers are vulnerable.
💻 Affected Systems
- Tenda M3 Router
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the router allowing attackers to intercept all network traffic, install persistent backdoors, pivot to internal networks, and use the device for botnet activities.
Likely Case
Router takeover leading to DNS hijacking, credential theft from network traffic, and use as a proxy for malicious activities.
If Mitigated
Limited impact if router is behind firewall with restricted WAN access and telnet disabled.
🎯 Exploit Status
Public GitHub repository contains exploit details and proof-of-concept. The vulnerability is in the telnet service which is often enabled by default.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not found
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 update
4. Verify telnet service is disabled
🔧 Temporary Workarounds
Disable Telnet Service
allDisable the telnet service which contains the vulnerable function
telnet service stop
disable telnet in router admin interface
Restrict Network Access
linuxBlock telnet port (23) at firewall and restrict router management interface access
iptables -A INPUT -p tcp --dport 23 -j DROP
iptables -A INPUT -s 192.168.1.0/24 -p tcp --dport 80 -j ACCEPT
🧯 If You Can't Patch
- Replace affected router with different model or vendor
- Place router behind dedicated firewall with strict ingress filtering
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface. If version is exactly V1.0.0.12(4856), the device is vulnerable.Check Version:
Check router web interface at 192.168.0.1 or 192.168.1.1 under System Status or About sectionVerify Fix Applied:
After update, verify firmware version changed from V1.0.0.12(4856). Test telnet service is not responding on port 23.📡 Detection & Monitoring
Log Indicators:
- Unusual telnet connection attempts
- Unexpected command execution in router logs
- Failed authentication attempts to telnet service
Network Indicators:
- Telnet traffic to router on port 23 from unexpected sources
- Unusual outbound connections from router
SIEM Query:
source="router.log" AND ("telnet" OR "TendaTelnet") AND ("exec" OR "command" OR "injection")