CVE-2021-29076
📋 TL;DR
This vulnerability allows unauthenticated attackers to execute arbitrary commands on affected NETGEAR WiFi systems. It affects RBK852, RBK853, RBK854, RBR850, and RBS850 devices running firmware versions before 3.2.17.12. Attackers can exploit this without any authentication, potentially gaining full control of the device.
💻 Affected Systems
- NETGEAR RBK852
- NETGEAR RBK853
- NETGEAR RBK854
- NETGEAR RBR850
- NETGEAR RBS850
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise leading to network infiltration, data exfiltration, ransomware deployment, or use as a pivot point for attacking other internal systems.
Likely Case
Device takeover enabling network traffic interception, credential theft, installation of persistent backdoors, or participation in botnets.
If Mitigated
Limited impact if devices are behind firewalls with strict inbound filtering and network segmentation prevents lateral movement.
🎯 Exploit Status
Exploit details are publicly available. The pre-authentication nature and high CVSS score make this attractive for attackers.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 3.2.17.12 or later
Vendor Advisory: https://kb.netgear.com/000063015/Security-Advisory-for-Pre-Authentication-Command-Injection-on-Some-WiFi-Systems-PSV-2020-0485
Restart Required: Yes
Instructions:
1. Log into NETGEAR Orbi web interface. 2. Navigate to Advanced > Administration > Firmware Update. 3. Check for updates and install version 3.2.17.12 or newer. 4. Reboot the device after installation completes.
🔧 Temporary Workarounds
Network Segmentation
allPlace affected devices in isolated network segments with strict firewall rules limiting inbound access.
Access Control Lists
allImplement ACLs to restrict management interface access to trusted IP addresses only.
🧯 If You Can't Patch
- Disable remote management and WAN-side administration interfaces
- Implement network monitoring for suspicious command execution patterns on these devices
🔍 How to Verify
Check if Vulnerable:
Check firmware version via web interface: Advanced > Administration > Firmware Update. If version is below 3.2.17.12, device is vulnerable.Check Version:
No CLI command available. Use web interface at Advanced > Administration > Firmware Update.Verify Fix Applied:
Confirm firmware version is 3.2.17.12 or higher in the same interface. Test that command injection attempts are blocked.📡 Detection & Monitoring
Log Indicators:
- Unusual command execution in system logs
- Multiple failed authentication attempts followed by successful command execution
- Suspicious process creation
Network Indicators:
- Unexpected outbound connections from the device
- Traffic to known malicious IPs
- Anomalous HTTP requests to management interface
SIEM Query:
source="netgear_orbi" AND (event_type="command_execution" OR process_name="sh" OR process_name="bash")