CVE-2022-26290
📋 TL;DR
CVE-2022-26290 is a command injection vulnerability in Tenda M3 routers that allows attackers to execute arbitrary commands on the device. This affects Tenda M3 router users running vulnerable firmware versions. Successful exploitation could lead to complete device compromise.
💻 Affected Systems
- Tenda M3 Router
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full router compromise allowing attacker to intercept all network traffic, install persistent backdoors, pivot to internal networks, and use the router for botnet activities.
Likely Case
Router takeover enabling network traffic monitoring, DNS hijacking, credential theft, and lateral movement to connected devices.
If Mitigated
Limited impact if router is behind firewall with restricted WAN access and proper network segmentation.
🎯 Exploit Status
Public exploit code exists showing simple HTTP POST exploitation. No authentication required to trigger the vulnerability.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Tenda for latest firmware updates
Vendor Advisory: Not publicly documented by vendor
Restart Required: Yes
Instructions:
1. Log into Tenda router admin interface. 2. Navigate to System Tools > Firmware Upgrade. 3. Download latest firmware from Tenda website. 4. Upload and install firmware. 5. Reboot router after installation.
🔧 Temporary Workarounds
Disable WAN Management Access
allPrevent external access to router management interface
Navigate to Advanced > System Tools > Remote Management and disable WAN access
Network Segmentation
allIsolate router management interface to separate VLAN
🧯 If You Can't Patch
- Replace affected router with different model/brand
- Place router behind firewall with strict inbound rules blocking all WAN access to management interfaces
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface. If version is 1.10 V1.0.0.12(4856) or earlier, assume vulnerable.Check Version:
curl -s http://router-ip/goform/getStatus | grep version or check web interfaceVerify Fix Applied:
Verify firmware version has been updated beyond vulnerable version and test that /goform/WriteFacMac endpoint no longer accepts malicious input.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /goform/WriteFacMac with shell metacharacters
- Unexpected command execution in system logs
Network Indicators:
- HTTP requests containing shell commands (;, |, &, $, etc.) to router management interface
- Unusual outbound connections from router
SIEM Query:
source="router-logs" AND (url="/goform/WriteFacMac" AND (content="*;*" OR content="*|*" OR content="*&*" OR content="*$(*"))