CVE-2021-20170
📋 TL;DR
CVE-2021-20170 is a hardcoded credential vulnerability in Netgear RAX43 routers that allows attackers to decrypt configuration backups using the password 'RAX50w!a4udk', modify restricted settings, and restore malicious configurations. This affects Netgear RAX43 router users running vulnerable firmware versions. Attackers with access to configuration backups can bypass intended security controls.
💻 Affected Systems
- Netgear RAX43
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete router compromise allowing attackers to change DNS settings, redirect traffic, disable security features, or gain persistent access to the network.
Likely Case
Unauthorized configuration changes leading to network disruption, credential theft, or installation of malicious firmware.
If Mitigated
Limited impact if configuration backups are properly secured and not accessible to unauthorized users.
🎯 Exploit Status
Exploitation requires access to configuration backup files and knowledge of the hardcoded password. The vulnerability is well-documented in security advisories.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Netgear support for latest firmware
Vendor Advisory: https://kb.netgear.com/000064437/Security-Advisory-for-Hardcoded-Credential-on-RAX43-PSV-2021-0010
Restart Required: Yes
Instructions:
1. Log into router admin interface. 2. Navigate to Advanced > Administration > Firmware Update. 3. Check for updates. 4. Download and install latest firmware. 5. Reboot router after update completes.
🔧 Temporary Workarounds
Disable configuration backup feature
allPrevent creation of configuration backups that could be exploited
Secure configuration backups
allStore configuration backups in encrypted locations with restricted access
🧯 If You Can't Patch
- Restrict access to router administration interface to trusted users only
- Monitor for unauthorized configuration changes and backup file access
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface. If version is 1.0.3.96, the device is vulnerable.Check Version:
Log into router web interface and check firmware version under Advanced > Administration > Firmware UpdateVerify Fix Applied:
Verify firmware version has been updated to a version later than 1.0.3.96 and test that configuration backups cannot be decrypted with the hardcoded password.📡 Detection & Monitoring
Log Indicators:
- Multiple configuration restore attempts
- Unexpected firmware version changes
- Unauthorized admin login attempts
Network Indicators:
- Unusual DNS server changes
- Unexpected network configuration modifications
SIEM Query:
source="router_logs" AND (event="configuration_restore" OR event="firmware_update")