CVE-2025-3989
📋 TL;DR
A critical buffer overflow vulnerability in TOTOLINK N150RT routers allows remote attackers to execute arbitrary code by manipulating the Hostname parameter in the formStaticDHCP function. This affects all systems running the vulnerable firmware version. Successful exploitation could lead to complete device compromise.
💻 Affected Systems
- TOTOLINK N150RT
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to full router compromise, persistence installation, network traffic interception, and lateral movement to connected devices.
Likely Case
Router takeover enabling DNS hijacking, credential theft, and botnet recruitment for DDoS attacks.
If Mitigated
Limited impact if device is behind firewall with strict inbound filtering and network segmentation.
🎯 Exploit Status
Public exploit code available on GitHub. No authentication required. Simple buffer overflow with predictable exploitation path.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: https://www.totolink.net/
Restart Required: Yes
Instructions:
1. Check vendor website for firmware updates. 2. Download latest firmware. 3. Access router admin interface. 4. Navigate to firmware upgrade section. 5. Upload new firmware file. 6. Wait for reboot and verify version.
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to router web interface
Access router admin > Advanced > Remote Management > Disable
Network Segmentation
linuxIsolate router management interface to trusted network
iptables -A INPUT -p tcp --dport 80 -s TRUSTED_NET -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
🧯 If You Can't Patch
- Replace affected devices with supported models
- Implement strict network ACLs blocking all inbound traffic to router management interface
🔍 How to Verify
Check if Vulnerable:
Check firmware version in router admin interface under System Status or Firmware Upgrade pageCheck Version:
curl -s http://router-ip/ | grep -i firmware || ssh admin@router 'cat /proc/version'Verify Fix Applied:
Verify firmware version is different from 3.4.0-B20190525 and no longer contains vulnerable code📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /boafrm/formStaticDHCP
- Multiple failed buffer overflow attempts
- Unexpected router reboots
Network Indicators:
- HTTP requests with long Hostname parameters to router IP
- Traffic patterns suggesting exploit delivery
SIEM Query:
source="router.log" AND (uri="/boafrm/formStaticDHCP" AND content_length>1000)