CVE-2020-21935
📋 TL;DR
This CVE describes a command injection vulnerability in the HNAP1/GetNetworkTomographySettings endpoint of Motorola CX2 routers. Attackers can exploit this to execute arbitrary code with high privileges. Users of affected Motorola CX2 router versions are at risk.
💻 Affected Systems
- Motorola CX2 router
📦 What is this software?
Cx2 Firmware by Motorola
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the router allowing attackers to intercept traffic, modify configurations, install persistent backdoors, and pivot to internal networks.
Likely Case
Router takeover leading to DNS hijacking, credential theft from connected devices, and network disruption.
If Mitigated
Limited impact if router is behind firewall with restricted WAN access and strong authentication.
🎯 Exploit Status
Public exploit code exists in GitHub repositories, making exploitation straightforward for attackers with network access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: No official vendor advisory found
Restart Required: No
Instructions:
No official patch available. Consider upgrading to newer router models or implementing workarounds.
🔧 Temporary Workarounds
Disable HNAP1 protocol
allDisable the HNAP1 protocol on the router if not required for functionality
Network segmentation
allPlace router in isolated network segment with strict firewall rules
🧯 If You Can't Patch
- Replace affected router with newer model that doesn't have this vulnerability
- Implement strict network access controls to limit exposure to the router's management interface
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via web interface or SSH. If version is CX 1.0.2 Build 20190508 Rel.97360n, it is vulnerable.Check Version:
Check router web interface at http://[router-ip]/ or use SSH if enabledVerify Fix Applied:
Verify firmware has been updated to a version newer than the affected build, though no official patch exists.📡 Detection & Monitoring
Log Indicators:
- Unusual HNAP1 protocol requests
- Suspicious command execution in router logs
- Unexpected configuration changes
Network Indicators:
- Unusual traffic to router management ports (typically 80/443)
- Suspicious payloads in HTTP requests to HNAP1 endpoints
SIEM Query:
source="router" AND (http_uri="*HNAP1*" OR http_uri="*GetNetworkTomographySettings*") AND http_method="POST"