CVE-2021-45599
📋 TL;DR
This vulnerability allows authenticated users to execute arbitrary commands on affected NETGEAR WiFi systems. It affects specific NETGEAR CBR40, CBR750, RBK852, 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 RBK852
- NETGEAR RBR850
- NETGEAR RBS850
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full device compromise leading to persistent backdoor installation, network traffic interception, lateral movement to other devices, and complete network takeover.
Likely Case
Attacker gains shell access to execute commands, potentially installing malware, modifying configurations, or using the device as a pivot point for further attacks.
If Mitigated
With proper network segmentation and strong authentication controls, impact is limited to the affected device only.
🎯 Exploit Status
Exploitation requires valid credentials but is straightforward once authenticated. No public exploit code has been released.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: CBR40: 2.5.0.24, CBR750: 4.6.3.6, RBK852/RBR850/RBS850: 3.2.17.12
Vendor Advisory: https://kb.netgear.com/000064145/Security-Advisory-for-Post-Authentication-Command-Injection-on-Some-WiFi-Systems-PSV-2020-0546
Restart Required: Yes
Instructions:
1. Log into NETGEAR router web interface. 2. Navigate to Advanced > Administration > Firmware Update. 3. Check for updates and install the latest firmware. 4. Reboot the device after installation completes.
🔧 Temporary Workarounds
Disable remote management
allPrevents external access to the vulnerable web interface
Implement strong authentication
allUse complex, unique passwords and enable multi-factor authentication if available
🧯 If You Can't Patch
- Segment affected devices on isolated network VLANs
- Implement strict firewall rules to limit management interface access to trusted IPs only
🔍 How to Verify
Check if Vulnerable:
Check firmware version in router web interface under Advanced > Administration > Firmware UpdateCheck Version:
curl -s http://routerlogin.net/currentsetting.htm | grep FirmwareVerify Fix Applied:
Verify firmware version matches or exceeds patched versions listed in fix_official section📡 Detection & Monitoring
Log Indicators:
- Unusual command execution in system logs
- Multiple failed login attempts followed by successful login
- Unexpected configuration changes
Network Indicators:
- Unusual outbound connections from router
- Traffic to known malicious IPs
- Port scanning originating from router
SIEM Query:
source="router" AND (event="command_injection" OR event="shell_execution" OR cmd="*;*" OR cmd="*|*")