CVE-2020-12126
📋 TL;DR
This CVE describes multiple authentication bypass vulnerabilities in the WAVLINK WN530H4 router's /cgi-bin/ endpoint. Attackers can access router settings without authentication, modify configurations, and cause denial of service. Users of WAVLINK WN530H4 routers with vulnerable firmware are affected.
💻 Affected Systems
- WAVLINK WN530H4
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete router compromise allowing attacker to change all settings, intercept traffic, install malware, and permanently disable the device.
Likely Case
Unauthorized access to router settings, configuration changes, and temporary denial of service affecting network connectivity.
If Mitigated
Limited impact if router is behind firewall, not internet-facing, and has strong network segmentation.
🎯 Exploit Status
Exploitation requires simple HTTP requests to vulnerable endpoints without authentication.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: No official vendor advisory found
Restart Required: Yes
Instructions:
1. Check WAVLINK website for firmware updates. 2. If update available, download and install via router admin interface. 3. Reboot router after update.
🔧 Temporary Workarounds
Disable remote management
allPrevent external access to router admin interface
Network segmentation
allIsolate router management interface to trusted network
🧯 If You Can't Patch
- Replace with different router model that receives security updates
- Implement strict firewall rules blocking all external access to router management interface
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface. If version is M30H4.V5030.190403 or earlier, assume vulnerable.Check Version:
Check router web interface or use nmap/router scanning tools to identify firmware versionVerify Fix Applied:
Verify firmware version has been updated to a version later than M30H4.V5030.190403📡 Detection & Monitoring
Log Indicators:
- Unauthenticated access to /cgi-bin/ endpoints
- Configuration changes from unauthorized IPs
Network Indicators:
- HTTP requests to router /cgi-bin/ without authentication
- Unusual configuration changes
SIEM Query:
source_ip NOT IN authorized_admin_ips AND (uri_path CONTAINS '/cgi-bin/' OR event_type='configuration_change')