CVE-2021-45597
📋 TL;DR
This vulnerability allows authenticated users to execute arbitrary commands on affected NETGEAR WiFi systems. It affects specific NETGEAR CBR40, CBR750, RBR850, and RBS850 devices running vulnerable firmware versions. Attackers with valid credentials can inject commands through the web interface.
💻 Affected Systems
- NETGEAR CBR40
- NETGEAR CBR750
- NETGEAR RBR850
- NETGEAR RBS850
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full device compromise allowing attackers to install persistent backdoors, intercept network traffic, pivot to internal networks, or use the device for botnet activities.
Likely Case
Local network compromise where attackers with valid credentials gain elevated privileges, modify device settings, or access connected devices.
If Mitigated
Limited impact if strong authentication controls, network segmentation, and proper access controls are implemented.
🎯 Exploit Status
Exploitation requires valid credentials but is straightforward once authenticated. No public exploit code has been disclosed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: CBR40: 2.5.0.24, CBR750: 4.6.3.6, RBR850: 3.2.17.12, RBS850: 3.2.17.12
Vendor Advisory: https://kb.netgear.com/000064142/Security-Advisory-for-Post-Authentication-Command-Injection-on-Some-WiFi-Systems-PSV-2020-0539
Restart Required: Yes
Instructions:
1. Log into NETGEAR router web interface. 2. Navigate to Advanced > Administration > Firmware Update. 3. Check for updates or manually download firmware from NETGEAR support site. 4. Upload and install the patched firmware version. 5. Reboot the device after installation.
🔧 Temporary Workarounds
Restrict web interface access
allLimit access to the router's web management interface to trusted IP addresses only.
Change default credentials
allEnsure strong, unique passwords are set for all administrative accounts.
🧯 If You Can't Patch
- Segment affected devices on isolated network VLANs
- Implement strict access controls and monitor for suspicious authentication attempts
🔍 How to Verify
Check if Vulnerable:
Check firmware version in router web interface under Advanced > Administration > Firmware UpdateCheck Version:
Login to router web interface and navigate to Advanced > Administration > Firmware Update to view current versionVerify Fix Applied:
Verify firmware version matches or exceeds patched versions: CBR40: 2.5.0.24+, CBR750: 4.6.3.6+, RBR850: 3.2.17.12+, RBS850: 3.2.17.12+📡 Detection & Monitoring
Log Indicators:
- Unusual command execution in system logs
- Multiple failed authentication attempts followed by successful login
- Unexpected configuration changes
Network Indicators:
- Unusual outbound connections from router
- Traffic patterns suggesting command and control activity
SIEM Query:
source="router_logs" AND (event="command_injection" OR event="shell_execution")