CVE-2021-20174
📋 TL;DR
This vulnerability exposes Netgear Nighthawk R6700 router credentials to interception by using unencrypted HTTP instead of HTTPS for web interface communication. Attackers on the same network can capture login credentials and other sensitive data transmitted to the router's admin interface. All users with the affected router model and firmware version are vulnerable.
💻 Affected Systems
- Netgear Nighthawk R6700
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers capture admin credentials, gain full router control, redirect traffic to malicious sites, install persistent malware, and compromise all connected devices.
Likely Case
Local network attackers capture admin credentials and reconfigure router settings, potentially enabling further attacks on connected devices.
If Mitigated
With HTTPS enabled or network segmentation, attackers cannot intercept credentials, limiting exposure to other vulnerabilities.
🎯 Exploit Status
Exploitation requires network access to intercept HTTP traffic; tools like Wireshark or ettercap can capture credentials.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.0.4.122 or later
Vendor Advisory: https://kb.netgear.com/000063978/Security-Advisory-for-Cleartext-Transmission-of-Sensitive-Information-on-Some-Routers-PSV-2021-0010
Restart Required: Yes
Instructions:
1. Log into router admin interface via current IP. 2. Navigate to Advanced > Administration > Router Update. 3. Check for updates and install latest firmware. 4. Reboot router after update completes.
🔧 Temporary Workarounds
Enable HTTPS manually
allForce HTTPS usage for admin interface if supported by firmware
Manual configuration via router web interface under Advanced > Administration > Remote Management
Network segmentation
allIsolate router management interface to separate VLAN
🧯 If You Can't Patch
- Disable remote management and only access router from wired connection
- Change admin password regularly and monitor for unauthorized configuration changes
🔍 How to Verify
Check if Vulnerable:
Check if accessing router web interface uses HTTP instead of HTTPS by examining URL in browserCheck Version:
Check router web interface under Advanced > Administration > Router StatusVerify Fix Applied:
Confirm firmware version is 1.0.4.122 or later and HTTPS is enforced for admin access📡 Detection & Monitoring
Log Indicators:
- Multiple failed login attempts
- Unexpected configuration changes
- Admin login from unusual IP addresses
Network Indicators:
- HTTP traffic to router admin interface containing credentials
- ARP spoofing or MITM activity on local network
SIEM Query:
source="router_logs" AND (event="admin_login" OR event="config_change")