CVE-2025-22900
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on Totolink N600R routers by exploiting a stack overflow in the setWanConfig function. Attackers can gain full control of affected devices, potentially compromising network security. Only Totolink N600R routers running specific vulnerable firmware versions are affected.
💻 Affected Systems
- Totolink N600R
📦 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
Remote code execution allowing attackers to modify router settings, intercept traffic, or use the device as a pivot point for further attacks.
If Mitigated
Limited impact if devices are behind firewalls with strict inbound filtering and network segmentation.
🎯 Exploit Status
Public proof-of-concept code exists on GitHub, making exploitation straightforward for attackers with basic skills.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Unknown
Restart Required: Yes
Instructions:
1. Check Totolink 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.
🔧 Temporary Workarounds
Disable WAN Management
allPrevent external access to router management interface
Access router admin panel -> Advanced Settings -> Remote Management -> Disable
Network Segmentation
allIsolate router management interface to internal network only
Configure firewall rules to block external access to router IP on ports 80/443
🧯 If You Can't Patch
- Replace affected routers with updated models or different vendors
- Implement strict network segmentation and firewall rules to limit router exposure
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via admin interface: System -> Firmware UpgradeCheck Version:
curl -s http://router-ip/cgi-bin/cstecgi.cgi | grep versionVerify Fix Applied:
Verify firmware version is newer than v4.3.0cu.7647_B20210106📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /cgi-bin/cstecgi.cgi with setWanCfg parameters
- Multiple failed login attempts followed by successful access
Network Indicators:
- Unusual outbound connections from router
- Traffic spikes to/from router management interface
SIEM Query:
source="router-logs" AND (uri="/cgi-bin/cstecgi.cgi" AND method="POST" AND params CONTAINS "setWanCfg")