CVE-2023-38930
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on affected Tenda routers via a stack overflow in the addWifiMacFilter function. Attackers can exploit this by sending specially crafted requests containing malicious deviceId parameters. Users of vulnerable Tenda router models with affected firmware versions are at risk.
💻 Affected Systems
- Tenda AC7
- Tenda F1203
- Tenda AC5
- Tenda AC9
- Tenda FH1205
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise leading to persistent backdoor installation, network traffic interception, credential theft, and lateral movement to other devices on the network.
Likely Case
Remote code execution allowing attackers to modify router settings, intercept traffic, or use the device as part of a botnet.
If Mitigated
Limited impact if devices are behind firewalls with strict inbound filtering and network segmentation.
🎯 Exploit Status
Public proof-of-concept code exists in GitHub repositories. The exploit requires no authentication and has low complexity due to the stack overflow vulnerability.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: No official vendor advisory found
Restart Required: Yes
Instructions:
1. Check Tenda website for firmware updates
2. If update available, download and install via web interface
3. Reboot router after installation
4. Verify firmware version is no longer vulnerable
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to router web interface
Network Segmentation
allIsolate vulnerable routers from critical network segments
🧯 If You Can't Patch
- Replace vulnerable routers with patched or different vendor models
- Implement strict firewall rules blocking all inbound traffic to router management interfaces
🔍 How to Verify
Check if Vulnerable:
Access router web interface, navigate to System Status or About page, check firmware version against affected versions list.Check Version:
curl -s http://router-ip/goform/getStatus | grep versionVerify Fix Applied:
After updating, verify firmware version is newer than affected versions. Test if addWifiMacFilter function still accepts malformed deviceId parameters.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /goform/addWifiMacFilter
- Large deviceId parameter values in web logs
- Router crash/reboot events
Network Indicators:
- Unusual outbound connections from router
- Traffic patterns suggesting router compromise
SIEM Query:
source="router_logs" AND (uri="/goform/addWifiMacFilter" OR deviceId.length>100)