CVE-2023-46574
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on TOTOLINK A3700R routers by exploiting the FileName parameter in the UploadFirmwareFile function. Attackers can gain full control of affected devices without authentication. Only TOTOLINK A3700R routers running specific vulnerable firmware versions are affected.
💻 Affected Systems
- TOTOLINK A3700R
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of router with persistent backdoor installation, network traffic interception, credential theft, and lateral movement to connected devices.
Likely Case
Router takeover leading to DNS hijacking, credential harvesting, and botnet recruitment for DDoS attacks.
If Mitigated
Limited impact if devices are behind firewalls with strict inbound filtering and firmware uploads disabled.
🎯 Exploit Status
Proof of concept available in GitHub repository. Exploitation requires sending crafted HTTP request to vulnerable endpoint.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: No
Instructions:
No official patch available. Check TOTOLINK website for firmware updates. If update available: 1. Download latest firmware from vendor site 2. Access router admin interface 3. Navigate to firmware update section 4. Upload new firmware file 5. Wait for reboot
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to router administration interface
Access router admin panel → System Tools → Remote Management → Disable
Block Firmware Upload Endpoint
linuxUse firewall rules to block access to vulnerable endpoint
iptables -A INPUT -p tcp --dport 80 -m string --string "UploadFirmwareFile" --algo bm -j DROP
iptables -A INPUT -p tcp --dport 443 -m string --string "UploadFirmwareFile" --algo bm -j DROP
🧯 If You Can't Patch
- Isolate affected routers in separate VLAN with strict firewall rules
- Implement network segmentation to limit lateral movement from compromised routers
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface under System Status or System Tools → Firmware UpgradeCheck Version:
curl -s http://router-ip/cgi-bin/cstecgi.cgi -X POST -d '{"topicurl":"setting/getMaintenanceInfo"}' | grep FirmwareVerify Fix Applied:
Verify firmware version has changed from v9.1.2u.6165_20211012 to newer version📡 Detection & Monitoring
Log Indicators:
- HTTP POST requests to /cgi-bin/cstecgi.cgi with UploadFirmwareFile parameter
- Unusual firmware upload activity
- System reboot logs after firmware upload
Network Indicators:
- HTTP traffic to router on port 80/443 containing UploadFirmwareFile string
- Unexpected outbound connections from router
SIEM Query:
source="router_logs" AND ("UploadFirmwareFile" OR "cstecgi.cgi") AND method="POST"