CVE-2021-41314
📋 TL;DR
This vulnerability allows unauthenticated attackers to inject newline characters in the password field of NETGEAR smart switch web UIs, bypassing authentication and gaining full administrative privileges. It affects multiple NETGEAR smart switch models with specific firmware versions. Attackers can craft admin sessions and take complete control of affected devices.
💻 Affected Systems
- GC108P
- GC108PP
- GS108Tv3
- GS110TPP
- GS110TPv3
- GS110TUP
- GS308T
- GS310TP
- GS710TUP
- GS716TP
- GS716TPP
- GS724TPP
- GS724TPv2
- GS728TPPv2
- GS728TPv2
- GS750E
- GS752TPP
- GS752TPv2
- MS510TXM
- MS510TXUP
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of network switching infrastructure, enabling traffic interception, VLAN hopping, network segmentation bypass, and persistent backdoor access to the entire network segment.
Likely Case
Unauthorized administrative access to smart switches, allowing configuration changes, traffic monitoring, and potential lateral movement to connected systems.
If Mitigated
Limited to isolated network segments with strict access controls, reducing potential for lateral movement and data exfiltration.
🎯 Exploit Status
Exploitation requires sending crafted HTTP requests to the web interface. Public technical details and proof-of-concept are available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Varies by model - see NETGEAR advisory for specific fixed versions
Vendor Advisory: https://kb.netgear.com/000063978/Security-Advisory-for-Multiple-Vulnerabilities-on-Some-Smart-Switches-PSV-2021-0140-PSV-2021-0144-PSV-2021-0145
Restart Required: Yes
Instructions:
1. Identify affected switch model and current firmware version. 2. Download appropriate firmware update from NETGEAR support site. 3. Upload firmware via web interface or TFTP. 4. Apply update and restart switch. 5. Verify new firmware version is installed.
🔧 Temporary Workarounds
Disable Web Management Interface
allDisable HTTP/HTTPS web management interface and use CLI or SNMP-only management
Switch-specific CLI commands vary by model - consult NETGEAR documentation
Network Access Control
allRestrict access to switch management interfaces using firewall rules or VLAN segmentation
🧯 If You Can't Patch
- Isolate affected switches in dedicated management VLAN with strict access controls
- Implement network monitoring for unauthorized access attempts to switch management interfaces
🔍 How to Verify
Check if Vulnerable:
Check current firmware version against affected versions list in NETGEAR advisoryCheck Version:
Web interface: System Information page. CLI: 'show version' or model-specific equivalentVerify Fix Applied:
Confirm firmware version matches or exceeds patched versions specified in NETGEAR advisory📡 Detection & Monitoring
Log Indicators:
- Multiple failed authentication attempts followed by successful login from unusual source
- Configuration changes from unexpected IP addresses
- Authentication logs showing newline characters in username/password fields
Network Indicators:
- HTTP POST requests to login.cgi with newline characters in parameters
- Unusual administrative traffic from non-management workstations
SIEM Query:
source="switch_logs" AND (message="*\n*" OR message="*%0A*") AND (url="*login*" OR action="*auth*")🔗 References
- https://gynvael.coldwind.pl/?id=742
- https://kb.netgear.com/000063978/Security-Advisory-for-Multiple-Vulnerabilities-on-Some-Smart-Switches-PSV-2021-0140-PSV-2021-0144-PSV-2021-0145
- https://gynvael.coldwind.pl/?id=742
- https://kb.netgear.com/000063978/Security-Advisory-for-Multiple-Vulnerabilities-on-Some-Smart-Switches-PSV-2021-0140-PSV-2021-0144-PSV-2021-0145
