from Hacker News

Virgin Media have an online activation process for their superhub users and at the end of the process they automatically reboot your router; but once this process is completed visiting this URL reboots your router regardless with no CSRF protection.

URL: http://activation.virginmedia.com/Activation/start.do

so a simple iframe on any webpage is enough to restart any virgin superhub users connection with a 3-5 minute reboot.

Proof of concept: http://jsfiddle.net/DmArd/