Hackers are claiming they have kidnapped children in a bid to infect PCs with a Trojan Horse virus, says Sophos.

The security firm is warning users that emails entitled 'We have hijacked your baby' are being sent to web users around the globe. As well as asking for a $50,000 (£25,000) ransom for the 'release' of the child, the messages also contain an attachement supposed to be a photograph of the child. Instead the file actually contains a deadly Trojan Horse that will steal personal information.

"Receiving or reading these widespread emails themselves does not mean you are infected, but if users open the attachment they will be infecting their Windows computer, they will give hackers an open door to take control and steal information," said Graham Cluley, senior technology consultant for Sophos.

"There's no other way of putting it - this attack is sick. Hackers have no qualms about exploiting a family's natural instinct to defend its most vulnerable members," added Cluley.