CVE-2023-37703
📋 TL;DR
This vulnerability in Tenda FH1203 routers allows remote attackers to execute arbitrary code via a stack overflow in the speed_dir parameter. Attackers can potentially take full control of affected devices. Users running Tenda FH1203 V2.0.1.6 firmware are affected.
💻 Affected Systems
- Tenda FH1203
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise 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 exploit code exists in GitHub repositories. The vulnerability requires network access to the router's web interface.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: Yes
Instructions:
1. Check Tenda's official website for firmware updates. 2. Download the latest firmware for FH1203. 3. Log into router admin panel. 4. Navigate to System Tools > Firmware Upgrade. 5. Upload and install the new firmware. 6. Reboot the router.
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to the router's web interface
Network Segmentation
allIsolate the router from critical internal networks
🧯 If You Can't Patch
- Replace the vulnerable device with a different model or vendor
- Implement strict firewall rules to block all inbound traffic to the router's management interface
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin panel under System Status or System Tools > Firmware UpgradeCheck Version:
Not applicable - check via web interfaceVerify Fix Applied:
Verify firmware version has been updated to a version later than V2.0.1.6📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to formSetSpeedWan endpoint
- Multiple failed login attempts followed by successful access
- Unexpected configuration changes
Network Indicators:
- Unusual outbound connections from router
- Traffic patterns suggesting device compromise
- Port scanning originating from router
SIEM Query:
source_ip=router_ip AND (uri_path="*formSetSpeedWan*" OR method=POST AND uri_contains="speed_dir")