CVE-2021-45401
📋 TL;DR
This CVE describes a command injection vulnerability in Tenda AC10U routers that allows remote attackers to execute arbitrary commands with root privileges. Attackers can exploit this by sending specially crafted requests to the setUsbUnload functionality. All users of affected Tenda AC10U routers with vulnerable firmware are at risk.
💻 Affected Systems
- Tenda AC10U AC1200 Smart Dual-band Wireless 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 malware, pivot to internal networks, and use the router as part of a botnet.
Likely Case
Router takeover leading to DNS hijacking, credential theft from network traffic, and installation of cryptocurrency miners or other malware.
If Mitigated
Limited impact if router is behind firewall with restricted WAN access and proper network segmentation.
🎯 Exploit Status
Public proof-of-concept available in GitHub repository. Exploitation requires network access to router's web interface.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: No
Instructions:
Check Tenda website for firmware updates. If update available, download and flash via web interface.
🔧 Temporary Workarounds
Disable remote management
allPrevent external access to router web interface
Access router settings > Advanced > System > Remote Management > Disable
Block web interface from WAN
linuxUse firewall to block external access to router management ports
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP
🧯 If You Can't Patch
- Replace router with different model/brand
- Place router behind dedicated firewall with strict inbound rules
🔍 How to Verify
Check if Vulnerable:
Check firmware version in router web interface: Login > Advanced > System > Firmware UpgradeCheck Version:
curl -s http://router-ip/goform/getStatus | grep versionVerify Fix Applied:
Verify firmware version is newer than V15.03.06.49_multi📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /goform/setUsbUnload
- Suspicious command execution in system logs
Network Indicators:
- Unusual outbound connections from router
- DNS queries to malicious domains from router
SIEM Query:
source="router.log" AND "setUsbUnload" AND ("deviceName" OR "doSystemCmd")