CVE-2020-26905
📋 TL;DR
This vulnerability allows attackers to obtain administrative credentials on certain NETGEAR WiFi systems, potentially leading to full device compromise. It affects specific NETGEAR CBR40, RBK752, RBR750, RBS750, RBK852, RBR850, and RBS850 devices running outdated firmware versions. Attackers could exploit this to gain unauthorized access and control over the affected routers.
💻 Affected Systems
- NETGEAR CBR40
- NETGEAR RBK752
- NETGEAR RBR750
- NETGEAR RBS750
- NETGEAR RBK852
- NETGEAR RBR850
- NETGEAR RBS850
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers gain administrative access, enabling them to reconfigure the router, intercept network traffic, deploy malware, or use the device as a pivot point into the internal network.
Likely Case
Unauthorized users or malware on the local network exploit the flaw to steal admin credentials, leading to device takeover and potential data exfiltration.
If Mitigated
With proper patching and network segmentation, the impact is limited to isolated device compromise without broader network access.
🎯 Exploit Status
Exploitation likely requires network access to the device but no authentication, making it straightforward for attackers on the same network.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: CBR40: 2.5.0.10; RBK752, RBR750, RBS750: 3.2.15.25; RBK852, RBR850, RBS850: 3.2.10.11
Vendor Advisory: https://kb.netgear.com/000062349/Security-Advisory-for-Admin-Credential-Disclosure-on-Some-WiFi-Systems-PSV-2020-0047
Restart Required: Yes
Instructions:
1. Log into the NETGEAR router's web interface. 2. Navigate to the firmware update section. 3. Check for and apply the latest firmware version specified above. 4. Restart the device after the update completes.
🔧 Temporary Workarounds
Network Segmentation
allIsolate affected routers from critical internal networks to limit potential lateral movement if exploited.
Disable Remote Management
allTurn off remote administration features to prevent internet-based exploitation.
🧯 If You Can't Patch
- Replace affected devices with updated models or from other vendors if patching is not feasible.
- Implement strict network access controls and monitor for unusual administrative login attempts.
🔍 How to Verify
Check if Vulnerable:
Access the router's web interface, navigate to the firmware or system info page, and compare the current version against the affected ranges listed above.Check Version:
Check via web interface; no standard CLI command available for these consumer devices.Verify Fix Applied:
After updating, confirm the firmware version matches or exceeds the patched versions specified in the fix_official section.📡 Detection & Monitoring
Log Indicators:
- Unusual admin login attempts from unexpected IP addresses
- Multiple failed login attempts followed by a successful one
Network Indicators:
- Suspicious traffic patterns indicating credential harvesting or unauthorized configuration changes
SIEM Query:
Example: 'source="router_logs" AND (event="admin_login" OR event="configuration_change") AND user="admin" AND result="success"'