CVE-2023-49424
📋 TL;DR
CVE-2023-49424 is a critical stack overflow vulnerability in Tenda AX12 routers that allows remote attackers to execute arbitrary code by sending specially crafted requests to the /goform/SetVirtualServerCfg endpoint. This affects all users running Tenda AX12 routers with firmware version V22.03.01.46. Successful exploitation could lead to complete device compromise.
💻 Affected Systems
- Tenda AX12
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote unauthenticated attacker gains full control of the router, enabling traffic interception, network pivoting, persistent backdoor installation, and bricking of the device.
Likely Case
Remote code execution leading to router compromise, allowing attackers to modify network settings, intercept traffic, or use the device as part of a botnet.
If Mitigated
Limited impact if the router is behind a firewall with restricted WAN access and proper network segmentation is implemented.
🎯 Exploit Status
Public proof-of-concept code is available in the GitHub references. The exploit requires sending a specially crafted HTTP POST request to the vulnerable endpoint.
🛠️ 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. If an update is available, download the latest firmware. 3. Log into the router admin interface. 4. Navigate to System Tools > Firmware Upgrade. 5. Upload and install the new firmware. 6. Reboot the router after installation.
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to the router's web interface by disabling remote management features.
Log into router admin > Advanced > System Tools > Remote Management > Disable
Firewall Restriction
linuxUse network firewalls to block external access to port 80/443 on the router's WAN interface.
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP
🧯 If You Can't Patch
- Isolate the router on a dedicated network segment with strict firewall rules limiting traffic to/from the device.
- Implement network monitoring to detect exploitation attempts and consider replacing the router with a patched or different model.
🔍 How to Verify
Check if Vulnerable:
Check the router firmware version via the web interface at System Status > Firmware Version. If it shows V22.03.01.46, the device is vulnerable.Check Version:
curl -s http://router-ip/goform/getStatus | grep version or check web interface manuallyVerify Fix Applied:
After updating firmware, verify the version no longer shows V22.03.01.46. Test by attempting to access /goform/SetVirtualServerCfg with monitoring for crash or unexpected behavior.📡 Detection & Monitoring
Log Indicators:
- HTTP POST requests to /goform/SetVirtualServerCfg with unusually long list parameter
- Router crash/reboot logs
- Memory corruption errors in system logs
Network Indicators:
- HTTP traffic to router IP on port 80/443 with POST to /goform/SetVirtualServerCfg
- Unusual outbound connections from router after exploitation
SIEM Query:
source="router_logs" AND (url="/goform/SetVirtualServerCfg" OR message="stack overflow" OR message="segmentation fault")