CVE-2021-45557
📋 TL;DR
This vulnerability allows authenticated users to execute arbitrary commands on affected NETGEAR switches through command injection. It affects multiple NETGEAR switch models running vulnerable firmware versions, potentially allowing attackers with network access to gain control of the device.
💻 Affected Systems
- NETGEAR GC108P
- GC108PP
- GS108Tv3
- GS110TPv3
- GS110TPP
- GS110TUP
- GS710TUP
- GS308T
- GS310TP
- GS716TP
- GS716TPP
- GS724TPP
- GS724TPv2
- GS728TPPv2
- GS728TPv2
- GS752TPv2
- GS752TPP
- GS750E
- MS510TXM
- MS510TXUP
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
An authenticated attacker could gain full administrative control of the switch, modify network configurations, intercept traffic, or use the device as a pivot point to attack other systems on the network.
Likely Case
An attacker with valid credentials could execute limited commands to disrupt network operations, modify VLAN configurations, or create backdoors for persistent access.
If Mitigated
With proper network segmentation and strong authentication controls, the impact is limited to the affected switch itself rather than the broader network.
🎯 Exploit Status
Exploitation requires valid credentials but is straightforward once authenticated. No public exploit code has been released.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: See affected_systems.versions for specific fixed versions per model
Vendor Advisory: https://kb.netgear.com/000064164/Security-Advisory-for-Post-Authentication-Command-Injection-on-Some-Switches-PSV-2021-0167
Restart Required: Yes
Instructions:
1. Download the appropriate firmware update from NETGEAR support site. 2. Log into the switch web interface. 3. Navigate to Maintenance > Firmware Upgrade. 4. Upload the firmware file. 5. Wait for upgrade to complete and device to reboot.
🔧 Temporary Workarounds
Restrict Management Access
allLimit management interface access to trusted IP addresses only
Configure ACLs to restrict web/SSH/Telnet access to management VLAN or specific IPs
Strengthen Authentication
allUse complex passwords and consider RADIUS/TACACS+ authentication
Configure strong local passwords or implement AAA server authentication
🧯 If You Can't Patch
- Isolate affected switches in separate VLAN with strict access controls
- Monitor for suspicious authentication attempts and command execution patterns
🔍 How to Verify
Check if Vulnerable:
Check firmware version in web interface under Maintenance > Firmware Version or via CLI using 'show version'Check Version:
show versionVerify Fix Applied:
Verify firmware version matches or exceeds the patched version listed in the advisory📡 Detection & Monitoring
Log Indicators:
- Unusual command execution in system logs
- Multiple failed authentication attempts followed by successful login
- Configuration changes from unexpected sources
Network Indicators:
- Unusual outbound connections from switch management interface
- Traffic patterns inconsistent with normal switch operations
SIEM Query:
source="netgear_switch" AND (event_type="command_execution" OR event_type="configuration_change")