CVE-2023-38940
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on affected Tenda routers via a stack overflow in the WiFi configuration function. Attackers can exploit this by sending specially crafted requests to the vulnerable parameter. Users of Tenda F1203, FH1203, and FH1205 routers with specific firmware versions are affected.
💻 Affected Systems
- Tenda F1203
- Tenda FH1203
- Tenda FH1205
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise leading to persistent remote access, network traffic interception, and lateral movement to connected devices.
Likely Case
Router takeover allowing attackers to modify network settings, intercept traffic, or use the device as a botnet node.
If Mitigated
Limited impact if devices are behind firewalls with strict inbound filtering and network segmentation.
🎯 Exploit Status
Public proof-of-concept available in GitHub repository. Exploitation requires sending HTTP request to vulnerable endpoint.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not found
Restart Required: Yes
Instructions:
1. Check Tenda website for firmware updates. 2. Download latest firmware for your model. 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
- Replace affected devices with supported models
- Implement strict firewall rules blocking all inbound traffic to router management interface
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via web interface at 192.168.0.1 or 192.168.1.1Check Version:
curl -s http://router-ip/goform/getStatus | grep versionVerify Fix Applied:
Verify firmware version is updated beyond affected versions📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP POST requests to /goform/fast_setting_wifi_set
- Multiple failed authentication attempts
- Unexpected configuration changes
Network Indicators:
- Unusual outbound connections from router
- Traffic to known malicious IPs
- DNS query anomalies
SIEM Query:
source="router_logs" AND (uri="/goform/fast_setting_wifi_set" OR method="POST" AND user_agent="*" AND size>1000)