A new worm is spreading over the internet using a variety of social engineering techniques, including pretending to be a legal summons or offering pictures of Paris Hilton.

Bagle-DO spreads in emails with subject lines such as 'Pay your debts before we come to you', 'Call to your lawer [sic] immidiately [sic]', 'Lawsuit against you,' and 'We wait your response'.

The emails urge the recipient to open the attached file, which can be called 'lawsuit.exe', 'explanation.exe' or 'documents.exe'. If executed the worm installs itself on the PC and looks for other computers to infect.

"People who receive this viral email won't necessarily believe that it was intended for them or their company, but they may wish to advise the apparent sender that they have sent the message to the wrong person," said Graham Cluley, senior technology consultant for Sophos.

"If anyone opens the attached file, however, they risk infecting their computer and passing on the pox to others."

The worm spreads onto other computers by harvesting email addresses and sending itself on using its own SMTP engine.

If the computer is running peer-to-peer software, it will install itself in the Shared Folder file claiming to be nude pictures of actress Kate Beckinsale, socialite Paris Hilton or pop starlet Britney Spears.