The worm is contained in an e-mail with titles including 'Naked World Cup Game Set' and 'Crazy Soccer Fans'.

Graham Cluley, from Internet security software giant Sophos, said:

"This worm exploits the public's interest in the World Cup to infect computer users.

"While some recipients might find nude football an attractive prospect, this is one worm you don't want to catch sight of, as you'll be playing straight into the hands of hackers."

It isn't the first time the lure of the World Cup has been used by hackers; earlier this year a German virus was spread by an e-mail offering tickets to the tournament, and in 2002, another offered score updates.