Research by Which magazine showed the SuperHub 2 router, used by Virgin Media has a flaw in which the default password can be cracked reasonably easily, with estimates of time taken varying from a couple of days, to a matter of minutes should hackers decide to attack the device.

Now security experts are warning that routers from other Internet Service Providers (ISPs) including BT, Sky, Talk Talk could have the same vulnerability.

The SuperHub 2, used by Virgin Media, used a default password comprised of single case letters only. This created a range of around 200 billion passwords, which sounds impressive, but which security specialists Lockdown estimate could be cracked within hours.

While it’s entirely possible to change the router’s default password, many users are unlikely to have done so, leaving themselves vulnerable to an attack.

Users with more recent devices should be unaffected. It does however highlight the fact that default passwords are notoriously insecure and should always be changed to something more secure as soon as possible.

If you’re bewildered about choosing passwords, the awesome XKCD provides some useful hints and tips.