CVE-2020-27872
📋 TL;DR
This vulnerability allows network-adjacent attackers to bypass authentication on NETGEAR R7450 routers by exploiting improper state tracking in the password recovery process. Attackers can leverage this with other vulnerabilities to execute code as root. Only users of affected NETGEAR router models are impacted.
💻 Affected Systems
- NETGEAR R7450
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full router compromise with root-level code execution, allowing attackers to intercept all network traffic, modify router settings, and use the router as a foothold into the internal network.
Likely Case
Authentication bypass leading to unauthorized access to router administration interface, potentially enabling configuration changes and credential theft.
If Mitigated
Limited impact if router is not internet-facing and network segmentation prevents lateral movement from compromised devices.
🎯 Exploit Status
Authentication not required. Exploit requires network adjacency and may need chaining with other vulnerabilities for full code execution.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Firmware version 1.2.0.62_1.0.1 or later (check NETGEAR advisory for exact fixed version)
Vendor Advisory: https://kb.netgear.com/000062641/Security-Advisory-for-Password-Recovery-Vulnerabilities-on-Some-Routers
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 router after update completes.
🔧 Temporary Workarounds
Disable remote administration
allPrevent external access to router web interface
Navigate to Advanced > Administration > Remote Management and disable
Change default admin password
allUse strong unique password for router administration
Navigate to Advanced > Administration > Set Password
🧯 If You Can't Patch
- Segment router management interface to isolated VLAN
- Implement network access controls to limit who can reach router administration interface
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface under Advanced > Administration > Firmware UpdateCheck Version:
Check router web interface or use nmap scan on port 80 to identify service versionVerify Fix Applied:
Verify firmware version is updated to patched version and test password recovery functionality📡 Detection & Monitoring
Log Indicators:
- Multiple failed authentication attempts followed by successful login
- Unusual password reset or recovery requests
- Access from unexpected IP addresses to admin interface
Network Indicators:
- Unusual HTTP requests to router port 80 containing password recovery parameters
- Traffic patterns suggesting router configuration changes
SIEM Query:
source="router_logs" AND (event="authentication" AND result="success" AND user="admin") OR (url CONTAINS "password" OR "recovery")🔗 References
- https://kb.netgear.com/000062641/Security-Advisory-for-Password-Recovery-Vulnerabilities-on-Some-Routers
- https://www.zerodayinitiative.com/advisories/ZDI-21-071/
- https://kb.netgear.com/000062641/Security-Advisory-for-Password-Recovery-Vulnerabilities-on-Some-Routers
- https://www.zerodayinitiative.com/advisories/ZDI-21-071/
