CVE-2020-15916
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary system commands on Tenda AC15 AC1900 routers via shell metacharacters in the lanIp parameter. Attackers can gain full control of affected devices without authentication. Users with Tenda AC15 AC1900 routers running vulnerable firmware are affected.
💻 Affected Systems
- Tenda AC15 AC1900
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of router with persistent backdoor installation, network traffic interception, credential theft, and pivot to internal network devices.
Likely Case
Router takeover leading to DNS hijacking, credential harvesting, and use as botnet node for DDoS attacks.
If Mitigated
Limited impact if device is behind firewall with no WAN access and proper network segmentation.
🎯 Exploit Status
Simple HTTP POST request with shell commands in lanIp parameter. Public exploit code available in security blogs.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Tenda website for latest firmware
Vendor Advisory: https://www.tendacn.com/support/download.html
Restart Required: Yes
Instructions:
1. Download latest firmware from Tenda website. 2. Log into router admin interface. 3. Navigate to System Tools > Firmware Upgrade. 4. Upload and install new firmware. 5. Reboot router.
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to router web interface
Network Segmentation
allIsolate router management interface to separate VLAN
🧯 If You Can't Patch
- Replace router with different vendor/model
- Place router behind firewall blocking access to port 80/443
🔍 How to Verify
Check if Vulnerable:
Check firmware version in router admin interface under System Status or System ToolsCheck Version:
curl -s http://router-ip/goform/AdvSetLanip (do not execute with malicious payload)Verify Fix Applied:
Verify firmware version is newer than 15.03.05.19 and test endpoint with safe payload📡 Detection & Monitoring
Log Indicators:
- HTTP POST requests to /goform/AdvSetLanip with shell metacharacters in parameters
- Unusual command execution in router logs
Network Indicators:
- HTTP traffic to router IP on port 80/443 with POST to vulnerable endpoint
- Outbound connections from router to suspicious IPs
SIEM Query:
http.method:POST AND http.uri:"/goform/AdvSetLanip" AND (http.param:*;* OR http.param:*|* OR http.param:*`*)