CVE-2018-21097
📋 TL;DR
This CVE describes a critical stack-based buffer overflow vulnerability in multiple NETGEAR wireless access point models. An unauthenticated attacker can exploit this remotely to execute arbitrary code or cause denial of service. Affected devices include WAC505, WAC510, WAC120, WN604, WNAP320, WNAP210v2, WNDAP350, WNDAP360, WNDAP660, WNDAP620, and WND930 running vulnerable firmware versions.
💻 Affected Systems
- WAC505
- WAC510
- WAC120
- WN604
- WNAP320
- WNAP210v2
- WNDAP350
- WNDAP360
- WNDAP660
- WNDAP620
- WND930
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing remote code execution, enabling attacker to pivot to internal networks, intercept traffic, or deploy persistent malware.
Likely Case
Remote denial of service causing device crashes and network disruption, potentially leading to extended downtime.
If Mitigated
Limited impact if devices are patched, isolated, or behind firewalls with strict access controls.
🎯 Exploit Status
The vulnerability requires no authentication and has a high CVSS score (9.8), suggesting relatively straightforward exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: WAC505/WAC510: 5.0.5.4, WAC120/WNDAP620: 2.1.7, WN604: 3.3.10, WNAP320/WNAP210v2/WNDAP350/WNDAP360/WNDAP660: 3.7.11.4, WND930: 2.1.5
Vendor Advisory: https://kb.netgear.com/000060457/Security-Advisory-for-Pre-Authentication-Stack-Overflow-on-Some-Wireless-Access-Points-PSV-2018-0094
Restart Required: Yes
Instructions:
1. Download the appropriate firmware update from NETGEAR support site. 2. Log into device web interface. 3. Navigate to Administration > Firmware Upgrade. 4. Upload the firmware file. 5. Wait for upgrade to complete and device to reboot.
🔧 Temporary Workarounds
Network Segmentation
allIsolate affected devices in separate VLANs with strict firewall rules limiting access to management interfaces.
Access Control Lists
allImplement network ACLs to restrict access to device management interfaces to trusted IP addresses only.
🧯 If You Can't Patch
- Replace vulnerable devices with updated models or different vendors
- Deploy intrusion prevention systems (IPS) with signatures for this vulnerability
🔍 How to Verify
Check if Vulnerable:
Check device firmware version via web interface: System > Status or Administration > FirmwareCheck Version:
No CLI command available - use web interface or check device label for hardware versionVerify Fix Applied:
Verify firmware version matches or exceeds patched versions listed in vendor advisory📡 Detection & Monitoring
Log Indicators:
- Unexpected device reboots
- Memory corruption errors in system logs
- Failed authentication attempts from unknown sources
Network Indicators:
- Unusual traffic patterns to device management ports
- Multiple connection attempts to vulnerable services
SIEM Query:
source="netgear-device" AND (event_type="crash" OR event_type="reboot") OR dest_port=80 AND http_user_agent="malicious-pattern"