SNMP vulnerability alert

You may have recently received a letter and/or email from Virgin Media explaining that we have been notified that a device on your network has a vulnerability known as an open Simple Network Management Protocol (SNMP) vulnerability. If you have received such a communication from us, please follow the advice given on this page to resolve the issue.

Overview

SNMP (Simple Network Management Protocol) is a method by which a device can be managed or accessed remotely on a computer network. An SNMP vulnerability is a security issue whereby a 3rd party can use this protocol to ultimately gain unauthorised access to your network/devices for malicious purposes, if the protocol is configured incorrectly.

What has happened?

We work with a number of not-for-profit organisations across the banking industry and security sectors that collate information on devices across the Internet that appear to be compromised or misconfigured. This means that your compromised or misconfigured device is publicly accessible on the Internet, and therefore the scanning that is performed by these organisations is not within your private network.

We suspect a device connected to your home network may have a SNMP vulnerability.

For more information on these reports please visit snmpscan.shadowserver.org **

If the settings are left open they can be exploited to unwittingly participate in malicious activities, for example a Distributed Denial of Service (DDoS) attack.

It is therefore important that you follow the advice in this article. *

How can the issue be fixed?

The easiest way to deal with SNMP threats/vulnerabilities is to configure your firewall to block UDP ports 161 and 162.

It is worth noting that blocking these ports will only stop traffic over that port leaving or entering your home network. Services within your home that use ports 161 and 162 should continue to work as normal.

Hub 3.0

To close the vulnerable port on the Virgin Media Hub 3.0:

  • Access your Hub's configuration page - default web address: 192.168.0.1
  • Login with your username and password, default will be shown on the Hub itself
  • Select Security on the left side of the page
  • Select the Port Forwarding option
  • Remove any rules that will keep ports 161 & 162 open
  • Select the Port Triggering option
  • Remove any rules that will keep ports 161 & 162 open

Virgin Media Superhub

To ensure ports 161 & 162 are closed on the Super Hub 1 or 2’s firewall:

  • Access your Hub's configuration page - default web address: 192.168.0.1
  • Login with your username and password, default will be shown on the Hub itself
  • Select Advanced Settings and accept the prompt
  • Scroll down to the Security section
  • Select the Port Forwarding option
  • Tick the Delete box next to any rules that will keep ports 161 & 162 open
  • Click the Apply option
  • Select the Port Triggering option
  • Tick the Delete box next to any rules that will keep ports 161 & 162 open
  • Click the Apply option

3rd party routers

If you use a 3rd party router in conjunction with the Virgin Media Super Hub or Hub 3.0, your router's firewall will need to be configured to ensure ports 161 and 162 are not accessible outside of your local network - this can be performed by blocking the port or removing any Port Forwarding rules for ports 161 and 162. In order to identify how to do this with your particular router, refer to the documentation for your device or refer to the manufacturer's website.

It is important to check all your devices sit behind a firewall. In most cases your firewall is configured as a part of your router, this is the case with the Virgin Media Super hub and Hub 3.0. If you have specifically disabled the Firewall in your router, it is crucial that you configure your devices to sit behind a firewall that blocks ports 161 and 162. If this does not apply to you, please proceed to the next step.

Modem Mode - If you are using your Virgin Media Super Hub or Hub 3.0 in Modem Only mode, it is essential that you are using a firewall on any device or router that is plugged directly into the Hub. When in Modem Only mode, your Hub does not operate with a firewall. If this does not apply to you, please proceed to the next step.

DMZ - Most firewalls, including the one provided with the Virgin Media Super Hub and Hub 3.0 include a DMZ option. This feature allows for a device using a specific local IP address on your home network (e.g. 192.168.0.2) to bypass your Firewall settings. This is occasionally necessary if you are using a device that has its own firewall configured. If you have a device configured in your firewall's DMZ that does not use its own firewall, it is crucial that you disable this option immediately. Computers operating without a firewall are extremely vulnerable to attack as all ports are essentially exposed to the wider Internet.

To check if a device is configured in the DMZ on your Virgin Media Super Hub 1 or 2:

  • Access your Hub's configuration page - default web address: 192.168.0.1
  • Login with your username and password, default will be shown on the Hub itself
  • Select Advanced Settings
  • Select DMZ
  • To remove a device from the DMZ, uncheck the tick box at the top of the page

To check if a device is configured in the DMZ on your Virgin Media Hub 3.0:

  • Access your Hub's configuration page - default web address: 192.168.0.1
  • Login with your username and password, default will be shown on the Hub itself
  • Select Security on the left side of the page
  • Select the DMZ option
  • To remove a device from the DMS, tick the Disable box

Where can I find further information and advice?

If you’d like further advice then our forum community will be happy to help. Just visit virginmedia.com/community and join the conversation on our Security Matters board.

You can find general security advice and articles on other vulnerabilities by checking Security Hub at virginmedia.com/securityhub

*Note: This article is intended to provide advice. Virgin Media is not responsible for any issues encountered in the course of resolving the issue and is not able to provide any technical support for such problems.

**Links to external sites are provided as a courtesy and virgin media is not responsible for the content of these sites or any issues encountered as a result of  applying information from these sites. Virgin media are not able to provide any technical support for such problems.

 


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