IT security experts have warned of a newly detected Trojan that disguises its malicious payload with a humorous animation.

Agent-FWO Trojan plays the popular Yes & No Shockwave video created by Italian animator Bruno Bozzetto, but only after embedding itself on the user's computer and downloading further malicious code from the internet.

Published on the internet by Bozzetto in 2001, 'Yes & No' is a humorous video about how obeying the rules of the road does not always make sense. Hundreds of thousands of people are believed to have watched the online animation.

But according to Sophos, the Trojan horse is playing the animation as a smokescreen while it silently infects Windows computers.

"It is important to realise that the animation itself is not malicious. The only negative aspect of funny movies like those created by Bozzetto and thousands of other artists could be the hours spent watching them," said Graham Cluley, senior technology consultant for Sophos.

"But the Trojan horse which is playing the animation in this instance is dangerous. It is exploiting society's predilection for forwarding humorous animations to friends and family in its attempt to infect as many people as possible."