CVE-2025-6302
📋 TL;DR
A critical stack-based buffer overflow vulnerability in TOTOLINK EX1200T routers allows remote attackers to execute arbitrary code by manipulating the Comment parameter in the setStaticDhcpConfig function. This affects TOTOLINK EX1200T routers running firmware version 4.1.2cu.5232_B20210713. Attackers can exploit this without authentication to potentially take full control of affected devices.
💻 Affected Systems
- TOTOLINK EX1200T
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, persistence installation, network pivoting, and data exfiltration.
Likely Case
Remote code execution allowing attackers to modify router settings, intercept traffic, or use the device as a botnet node.
If Mitigated
Denial of service or limited impact if proper network segmentation and access controls prevent exploitation.
🎯 Exploit Status
Public exploit details available; remote exploitation without authentication makes weaponization likely.
🛠️ 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 EX1200T. 3. Access router web interface. 4. Navigate to firmware upgrade section. 5. Upload and apply new firmware. 6. Reboot router.
🔧 Temporary Workarounds
Disable remote management
allPrevent external access to router web interface
Network segmentation
allIsolate router management interface to trusted network
🧯 If You Can't Patch
- Block access to /cgi-bin/cstecgi.cgi at network perimeter
- Implement strict firewall rules limiting management interface access to trusted IPs only
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via web interface or SSH: System Information > Firmware VersionCheck Version:
curl -s http://router-ip/cgi-bin/cstecgi.cgi | grep versionVerify Fix Applied:
Verify firmware version is updated beyond 4.1.2cu.5232_B20210713📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /cgi-bin/cstecgi.cgi with long Comment parameters
- Multiple buffer overflow attempts in system logs
Network Indicators:
- HTTP requests with oversized Comment parameter to router management interface
- Unusual outbound connections from router
SIEM Query:
source="router_logs" AND uri="/cgi-bin/cstecgi.cgi" AND method="POST" AND (param="Comment" AND length>100)