Russians behind zombie PC threat

Cyber criminals are believed to have launched a renewed campaign to invade millions of home computers across the world with a so-called 'trojan', creating an international network of infected zombie computers which can then be used at will to send spam or even launch cyber attacks on websites - without the owner's knowledge.

The campaign is likely to peak on or around St Valentine's Day, the day of the year when people are most likely to click on an anonymous email and open the link inside.

The threat is a return of 2007's devastating 'Storm' trojan. Storm arrived almost exactly a year ago via a spam email headed '230 dead as storm batter Europe'. Clicking the link in the email's body was enough to infect a PC.

Storm-watchers believe they're seeing a resurgence, and have already begun

intercepting St Valentine's Day messages hiding nasty surprises. Infected emails, with headings such as 'A Kiss Is So Gentle' and 'I Love You Because', carry a web address, much like a legitimate electronic greeting card. Click on the link and your own computer could be moonlighting for the criminals.

News of the Storm resurgence follows hard on the heels of concerns about a particularly vicious new virus called Mebroot, discovered earlier this month.

Mebroot exploits a weakness in Microsoft's Internet Explorer browser to install itself, via innocuous-looking websites, within the heart of a PC's operating system. Once there, it surreptitiously downloads a variety of keylogging applications, designed to recognise as many as 900 financial websites, record a user's keystrokes and forward login information to the criminals. Virus guards have proved ineffectual against Mebroot and it is difficult to tell if a computer is infected.

The really bad news is that, according to analysts, both the resurgent Storm and Mebroot carry digital DNA associated with