Software used to control thousands of home computers has been acquired online by the BBC as part of an investigation into global cyber crime.
The technology programme Click has demonstrated just how at risk PCs are of being taken over by hackers. Almost 22,000 computers made up Click's network of hijacked machines, which has now been disabled. The BBC has now warned users that their PCs are infected, and advised them on how to make their systems more secure.
Click managed to acquire its own low-value botnet - the name given to a network of hijacked computers - after visiting chatrooms on the internet. The programme did not access any personal information on the infected PCs. If this exercise had been done with criminal intent it would be breaking the law. But our purpose was to demonstrate botnets' collective power when in the hands of criminals. Click ordered its PCs to send out spam to two specific test e-mail addresses set up by the programme. Within hours, the inboxes started to fill up with thousands of junk messages. But a botnet can also be used to launch a concerted attack on commercial websites to take them out of action.