CVE-2021-45504
📋 TL;DR
This vulnerability allows attackers to bypass authentication on certain NETGEAR WiFi systems, potentially gaining unauthorized access to device administration interfaces. Affected devices include specific models of NETGEAR Orbi and Nighthawk routers and mesh systems running vulnerable firmware versions.
💻 Affected Systems
- NETGEAR CBR40
- NETGEAR CBR750
- NETGEAR RBR852
- NETGEAR RBR850
- NETGEAR RBS850
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the network device allowing attacker to reconfigure network settings, intercept traffic, install malware, or pivot to other internal systems.
Likely Case
Unauthorized access to router administration panel leading to network configuration changes, DNS hijacking, or credential theft.
If Mitigated
Limited impact if device is not internet-facing and network segmentation prevents lateral movement from compromised device.
🎯 Exploit Status
Authentication bypass vulnerabilities typically require minimal technical skill to exploit once details are known.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: CBR40: 2.5.0.24+, CBR750: 4.6.3.6+, RBR852/RBR850/RBS850: 3.2.17.12+
Vendor Advisory: https://kb.netgear.com/000064128/Security-Advisory-for-Authentication-Bypass-on-Some-WiFi-Systems-PSV-2020-0475
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. Reboot device after update completes.
🔧 Temporary Workarounds
Disable Remote Management
allPrevents external attackers from accessing the admin interface from the internet
Network Segmentation
allIsolate affected devices to separate VLAN to limit potential damage
🧯 If You Can't Patch
- Replace affected devices with patched models or alternative vendors
- Implement strict network access controls to limit access to device admin interfaces
🔍 How to Verify
Check if Vulnerable:
Check firmware version in router admin interface under Advanced > Administration > Firmware UpdateCheck Version:
No CLI command - check via web interface at router IP addressVerify Fix Applied:
Confirm firmware version matches or exceeds patched versions listed in vendor advisory📡 Detection & Monitoring
Log Indicators:
- Unauthorized access attempts to admin interface
- Multiple failed login attempts followed by successful access
- Configuration changes from unexpected IP addresses
Network Indicators:
- Unusual traffic patterns to router admin ports (typically 80/443)
- External IP addresses accessing internal router management interface
SIEM Query:
source_ip=external AND dest_port IN (80,443) AND dest_ip=router_ip AND user_agent NOT CONTAINS 'expected_user_agents'