CVE-2023-27063
📋 TL;DR
This vulnerability is a buffer overflow in Tenda W15EV1 routers via the DNSDomainName parameter in the formModifyDnsForward function. Attackers can exploit it to cause Denial of Service (DoS) through crafted requests. Affected users are those running vulnerable Tenda router firmware versions.
💻 Affected Systems
- Tenda W15EV1 router
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete router crash requiring physical reboot, potential remote code execution if buffer overflow can be controlled precisely (though not confirmed in description).
Likely Case
Router becomes unresponsive, requiring reboot to restore functionality, disrupting network connectivity.
If Mitigated
Limited to DoS impact if proper network segmentation and access controls prevent exploitation attempts.
🎯 Exploit Status
Public GitHub repository contains vulnerability details and likely exploit code. The buffer overflow via DNSDomainName parameter suggests straightforward exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not found in provided references
Restart Required: Yes
Instructions:
1. Check Tenda official website for firmware updates. 2. If update available, download and install via router web interface. 3. Reboot router after installation.
🔧 Temporary Workarounds
Disable remote management
allPrevent external access to router management interface
Access router web interface -> Advanced Settings -> Remote Management -> Disable
Restrict management interface access
allLimit which IP addresses can access router management
Access router web interface -> Security -> Access Control -> Add allowed IP ranges only
🧯 If You Can't Patch
- Replace affected router with different model/vendor
- Place router behind firewall with strict inbound rules blocking management ports
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in web interface: System Status -> Firmware VersionCheck Version:
Not applicable - check via web interfaceVerify Fix Applied:
Verify firmware version is newer than V15.11.0.14(1521_3190_1058)📡 Detection & Monitoring
Log Indicators:
- Multiple failed login attempts to router interface
- Unusual POST requests to formModifyDnsForward endpoint
Network Indicators:
- Unusual traffic to router management port (typically 80/443)
- Large DNSDomainName parameter values in HTTP requests
SIEM Query:
source_ip="router_ip" AND (url_path="/goform/ModifyDnsForward" OR url_path CONTAINS "formModifyDnsForward") AND http_method="POST"