U.K. businesses hit by weekend virus blitz

The PWSteal.Tarno.S virus arrived via attachment in an email claiming to be from Paypal. According to managed email services company BlackSpider Technologies, the trojan was was first seen at 4:55 a.m. on Saturday morning and increased in volume throughout Sunday. Eventually, anti-virus signatures for the virus were released this morning, leaving users unprotected for two days.

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."