CVE-2021-45615
📋 TL;DR
This vulnerability allows unauthenticated attackers to execute arbitrary commands on affected NETGEAR routers and WiFi systems through command injection. It affects multiple NETGEAR models with specific firmware versions, enabling remote code execution without authentication.
💻 Affected Systems
- NETGEAR CBR40
- CBR750
- R7900P
- R7960P
- R8000P
- R8300
- R8500
- RBK752
- RBR750
- RBS750
- RBK852
- RBR850
- RBS850
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the router, allowing attacker to intercept all network traffic, install persistent malware, pivot to internal network devices, and use the device for botnet activities.
Likely Case
Router takeover leading to DNS hijacking, credential theft from network traffic, and installation of backdoors for persistent access.
If Mitigated
Limited impact if device is behind firewall with restricted WAN access, though local network attacks remain possible.
🎯 Exploit Status
Exploitation requires no authentication and has been weaponized in the wild. The vulnerability is in the web interface and can be triggered remotely.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: CBR40 2.5.0.24+, CBR750 4.6.3.6+, R7900P 1.4.2.84+, R7960P 1.4.2.84+, R8000P 1.4.2.84+, R8300 1.0.2.154+, R8500 1.0.2.154+, RBK752 3.2.17.12+, RBR750 3.2.17.12+, RBS750 3.2.17.12+, RBK852 3.2.17.12+, RBR850 3.2.17.12+, RBS850 3.2.17.12+
Vendor Advisory: https://kb.netgear.com/000064514/Security-Advisory-for-Pre-Authentication-Command-Injection-on-Some-Routers-and-WiFi-Systems-PSV-2020-0521
Restart Required: Yes
Instructions:
1. Log into router web interface. 2. Navigate to Advanced > Administration > Firmware Update. 3. Check for updates. 4. If update available, download and install. 5. Router will reboot automatically.
🔧 Temporary Workarounds
Disable remote management
allPrevents external attackers from accessing the vulnerable web interface
Restrict WAN access
allUse firewall rules to block external access to router management interface
🧯 If You Can't Patch
- Replace affected device with patched model
- Place device behind dedicated firewall with strict inbound rules
🔍 How to Verify
Check if Vulnerable:
Check current firmware version in router web interface under Advanced > Administration > Firmware UpdateCheck Version:
No CLI command; check via web interface at Advanced > Administration > Firmware UpdateVerify Fix Applied:
Verify firmware version matches or exceeds patched versions listed in vendor advisory📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to router web interface
- Multiple failed login attempts followed by successful command execution
- Unexpected system processes or services running
Network Indicators:
- Unusual outbound connections from router
- DNS queries to suspicious domains
- Traffic redirection patterns
SIEM Query:
source="router_logs" AND (http_method="POST" AND uri="/cgi-bin/*" AND status="200") AND NOT user_agent="browser_user_agent"