Some 3.2 million emails containing a password stealing virus plagued the businesses of the UK over the weekend. PWSteal.Tarno.S virus is delivered via an attachment, as part of a mail claiming to be from Paypal. The trojan was first seen at 4:55 a.m. on Saturday morning, and increased in numbers drastically by Sunday. Anti-virus signatures for the virus were released today, but this did mean two days of users being unprotected.

James Kay, chief technology officer at BlackSpider Technologies, said that the virus caught the anti-virus community off-guard.

"The hacker behind this virus has done a real number on the anti-virus community. The virus was spammed out and we have seen it in enormous numbers," he said. "It was hardly a discrete attack, so I'm at a loss as to why it took an anti-virus vendor so long to take action. I'm sure the hacker can't believe their luck – a virus that went out early Saturday was still unpatched two days later."