CVE-2021-45551
📋 TL;DR
This vulnerability allows authenticated users on affected NETGEAR routers to execute arbitrary commands through command injection. Attackers with valid credentials can potentially gain full control of the device. It impacts multiple NETGEAR router models running outdated firmware versions.
💻 Affected Systems
- NETGEAR D6200
- D7000
- R6020
- R6080
- R6050
- JR6150
- R6120
- R6220
- R6230
- R6260
- R6800
- R6700v2
- R6900v2
- R7450
- AC2100
- AC2400
- AC2600
- WNR2020
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the router allowing attackers to intercept traffic, modify DNS settings, install persistent malware, and pivot to internal networks.
Likely Case
Unauthorized configuration changes, credential theft, and installation of backdoors by attackers with stolen or default credentials.
If Mitigated
Limited impact if strong authentication is enforced and network segmentation isolates routers from critical systems.
🎯 Exploit Status
Exploitation requires authentication but is straightforward once credentials are obtained. Public exploit code exists.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Minimum versions specified in CVE description (e.g., D6200 1.1.00.40 or later)
Vendor Advisory: https://kb.netgear.com/000064056/Security-Advisory-for-Post-Authentication-Command-Injection-on-Some-Routers-PSV-2019-0022
Restart Required: Yes
Instructions:
1. Log into router admin interface. 2. Navigate to firmware update section. 3. Download latest firmware from NETGEAR support site. 4. Upload and install firmware. 5. Reboot router after installation.
🔧 Temporary Workarounds
Change default credentials
allChange router admin password from default to strong, unique password
Disable remote administration
allTurn off remote management features to prevent external access
🧯 If You Can't Patch
- Isolate router on separate VLAN with strict firewall rules
- Implement network monitoring for suspicious router configuration changes
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface and compare against patched versions listed in CVECheck Version:
Log into router web interface and check firmware version in settingsVerify Fix Applied:
Confirm firmware version matches or exceeds minimum patched version specified in CVE📡 Detection & Monitoring
Log Indicators:
- Unusual configuration changes in router logs
- Multiple failed login attempts followed by successful login
Network Indicators:
- Unexpected outbound connections from router
- DNS hijacking or unusual DNS queries
SIEM Query:
source="router_logs" AND (event="configuration_change" OR event="firmware_update")