CVE-2025-55893
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary commands on TOTOLINK N200RE routers by injecting malicious input into the hostName parameter of the setOpModeCfg function. Attackers can gain full control of affected devices, potentially compromising network security. Only users of specific TOTOLINK router models with vulnerable firmware are affected.
💻 Affected Systems
- TOTOLINK N200RE
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device takeover leading to persistent backdoor installation, network traffic interception, lateral movement to other devices, and participation in botnets.
Likely Case
Router compromise allowing attackers to modify network settings, intercept traffic, and use the device as a pivot point for further attacks.
If Mitigated
Limited impact if devices are behind firewalls with strict inbound filtering and command injection protections are implemented.
🎯 Exploit Status
Exploit requires authentication to the router's web interface. Proof-of-concept available in public repository.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: https://www.totolink.net/
Restart Required: Yes
Instructions:
1. Check TOTOLINK website for firmware updates. 2. Download latest firmware for N200RE. 3. Log into router web interface. 4. Navigate to System Tools > Firmware Upgrade. 5. Upload new firmware file. 6. Wait for automatic reboot.
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to router web interface
Input Validation via Firewall
linuxBlock requests containing command injection patterns
iptables -A INPUT -p tcp --dport 80 -m string --string "hostName" --algo bm -j DROP
🧯 If You Can't Patch
- Isolate affected routers in separate VLAN with strict access controls
- Implement network segmentation to limit lateral movement potential
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in web interface under System Status > Firmware VersionCheck Version:
curl -s http://router-ip/cgi-bin/luci/ | grep -i firmwareVerify Fix Applied:
Verify firmware version has been updated to a version later than V9.3.5u.6437_B20230519📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to setOpModeCfg endpoint
- Commands containing semicolons, pipes, or backticks in hostName parameter
Network Indicators:
- Unusual outbound connections from router to unknown IPs
- Traffic patterns suggesting command-and-control communication
SIEM Query:
source="router.log" AND ("setOpModeCfg" OR "hostName") AND ("|" OR ";" OR "`" OR "$")