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."