CVE-2021-45543
📋 TL;DR
This vulnerability allows authenticated users on certain NETGEAR routers and WiFi systems to execute arbitrary commands through command injection. Attackers with valid credentials can potentially gain full control of affected devices. The issue affects multiple NETGEAR models running specific firmware versions.
💻 Affected Systems
- NETGEAR R8000
- NETGEAR RAX200
- NETGEAR R8000P
- NETGEAR R7900P
- NETGEAR RBR850
- NETGEAR RBS850
- NETGEAR RBK852
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing attacker to install persistent malware, intercept all network traffic, pivot to internal networks, and use device as part of botnet.
Likely Case
Local network compromise where authenticated attacker gains administrative control over router, enabling traffic interception, DNS manipulation, and credential theft.
If Mitigated
Limited to authenticated users only, reducing exposure to authorized personnel or attackers who have already compromised valid credentials.
🎯 Exploit Status
Command injection vulnerabilities typically have low exploitation complexity once authentication is bypassed or obtained. No public exploit code identified in references.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: R8000: 1.0.4.74+, RAX200: 1.0.4.120+, R8000P: 1.4.2.84+, R7900P: 1.4.2.84+, RBR850: 3.2.17.12+, RBS850: 3.2.17.12+, RBK852: 3.2.17.12+
Vendor Advisory: https://kb.netgear.com/000064517/Security-Advisory-for-Post-Authentication-Command-Injection-on-Some-Routers-and-WiFi-Systems-PSV-2020-0541
Restart Required: Yes
Instructions:
1. Log into router admin interface. 2. Navigate to Advanced > Administration > Firmware Update. 3. Check for updates and apply latest firmware. 4. Router will reboot automatically after update.
🔧 Temporary Workarounds
Disable remote administration
allPrevents external attackers from accessing admin interface
Implement strong authentication
allUse complex passwords and enable multi-factor authentication if available
🧯 If You Can't Patch
- Isolate affected routers in separate VLAN with strict access controls
- Implement network monitoring for unusual router traffic patterns
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via admin interface: Advanced > Administration > Firmware UpdateCheck Version:
No CLI command available - must use web interfaceVerify Fix Applied:
Verify firmware version matches or exceeds patched versions listed in advisory📡 Detection & Monitoring
Log Indicators:
- Unusual command execution in router logs
- Multiple failed login attempts followed by successful login
Network Indicators:
- Unusual outbound connections from router
- DNS changes not initiated by administrator
SIEM Query:
source="router_logs" AND (command="*;*" OR command="*|*" OR command="*`*" OR command="*$(*")