CVE-2023-39672
📋 TL;DR
CVE-2023-39672 is a critical buffer overflow vulnerability in Tenda WH450 routers caused by improper bounds checking in the fgets function. This allows remote attackers to execute arbitrary code on affected devices. Users of Tenda WH450 routers with firmware version 1.0.0.18 are vulnerable.
💻 Affected Systems
- Tenda WH450
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise leading to remote code execution, persistent backdoor installation, network traffic interception, and lateral movement to other devices on the network.
Likely Case
Router takeover allowing attackers to modify DNS settings, intercept traffic, deploy malware to connected devices, or use the router as part of a botnet.
If Mitigated
Limited impact with proper network segmentation and firewall rules preventing external access to router management interfaces.
🎯 Exploit Status
The vulnerability is in a network-facing service, making remote exploitation straightforward with available proof-of-concept code.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Tenda website for latest firmware
Vendor Advisory: https://www.tendacn.com/download/list-3.html
Restart Required: Yes
Instructions:
1. Visit Tenda's download page for WH450. 2. Download the latest firmware version. 3. Log into router admin interface. 4. Navigate to System Tools > Firmware Upgrade. 5. Upload and install the new firmware. 6. Wait for router to reboot.
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to router management interface
Network Segmentation
allIsolate router management interface to trusted network segment
🧯 If You Can't Patch
- Replace affected routers with patched or alternative devices
- Implement strict firewall rules blocking all external access to router management ports
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface under System Status or System ToolsCheck Version:
Login to router web interface and check System Status pageVerify Fix Applied:
Confirm firmware version is updated to a version later than v1.0.0.18📡 Detection & Monitoring
Log Indicators:
- Unusual authentication attempts to router management interface
- Multiple failed connection attempts followed by successful access
- Unexpected firmware modification logs
Network Indicators:
- Unusual outbound connections from router
- DNS hijacking patterns
- Traffic redirection to unexpected destinations
SIEM Query:
source="router_logs" AND (event_type="authentication" AND result="failure" AND count>10) OR (event_type="firmware_update" AND user!="admin")