CVE-2023-40830
📋 TL;DR
CVE-2023-40830 is a buffer overflow vulnerability in Tenda AC6 routers where the Index parameter lacks length validation. This allows attackers to execute arbitrary code remotely, affecting all users of vulnerable Tenda AC6 routers with default configurations.
💻 Affected Systems
- Tenda AC6
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete router compromise, credential theft, network traffic interception, and lateral movement to connected devices.
Likely Case
Router takeover enabling DNS hijacking, credential harvesting, and persistent backdoor installation for ongoing surveillance.
If Mitigated
Limited impact with proper network segmentation and firewall rules preventing external access to router management interface.
🎯 Exploit Status
Public exploit code exists in GitHub repositories. The vulnerability requires no authentication and has simple exploitation steps.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Tenda website for latest firmware > v15.03.05.19
Vendor Advisory: Not publicly available
Restart Required: Yes
Instructions:
1. Visit Tenda support website. 2. Download latest firmware for AC6 model. 3. Log into router admin panel. 4. Navigate to System Tools > Firmware Upgrade. 5. Upload and install new firmware. 6. Reboot router.
🔧 Temporary Workarounds
Disable WPS and Remote Management
allDisable WiFi Protected Setup and remote management features to reduce attack surface
Network Segmentation
linuxIsolate router management interface from untrusted networks
iptables -A INPUT -p tcp --dport 80 -s ! 192.168.1.0/24 -j DROP
iptables -A INPUT -p tcp --dport 443 -s ! 192.168.1.0/24 -j DROP
🧯 If You Can't Patch
- Replace vulnerable router with patched or alternative model
- Implement strict firewall rules blocking all external access to router management interface (ports 80/443)
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin panel under System Status. If version is exactly v15.03.05.19, device is vulnerable.Check Version:
curl -s http://router-ip/goform/getStatus | grep versionVerify Fix Applied:
After firmware update, verify version has changed from v15.03.05.19. Test WifiWpsOOB endpoint with malformed requests.📡 Detection & Monitoring
Log Indicators:
- Multiple POST requests to /goform/WifiWpsOOB with long Index parameters
- Unusual process execution in router logs
- Failed authentication attempts followed by buffer overflow patterns
Network Indicators:
- Unusual traffic to router management interface from external IPs
- POST requests with abnormally long parameters to WifiWpsOOB endpoint
- Sudden changes in router DNS settings
SIEM Query:
source="router_logs" AND (uri_path="/goform/WifiWpsOOB" AND parameter_length>1000) OR (event_type="buffer_overflow" AND device_model="Tenda AC6")