Panda Software warns that this Valentine’s Day, instead of receiving flowers and chocolates, you may get a nasty virus on your computer.

The security technology company has detected the mass mailing of messages containing the Nurech.A worm.

Within the first few hours of spreading, hundreds of computers were already infected, resulting in it being given an Orange virus status and being named as one of the top ten viruses detected by the company’s ActiveScan tool.

The worm infects computers through emails with a variety of Valentine’s-related subject titles such as
‘Together You and I’ and ‘Everyone Needs Someone’. The worm is contained within an attached file with names such as flash postcard.exe or greeting postcard.exe.

Technical director of PandaLabs, Luis Corrons, has advised people not to open any “suspicious email, regardless of what it says it contains” and to “let a security solution decide whether it’s safe to open or not”.

Panda Software also warns of the increase in phishing attacks at this time of year with people potentially opening themselves up to being duped when buying Valentine’s gifts online. Sophos, meanwhile, has reminded users to type web addresses into the browser’s address bar instead of clicking on links arriving by email.

As well as worms rapidly spreading and infecting hundreds of computers, Sophos reports that there's also an increase in the number of spam emails selling romantic gifts. However a poll conducted by the security company shows that only 5 percent of computer users actually admitted to buying goods after receiving the spam email, compared to 9 percent the previous year.

Senior technology consultant at Sophos, Graham Cluley, said that spammers are not facing an “easy ride when it comes to flogging goods” and it is “encouraging to see a drop in the number of people who own up to making purchases”. He also highlighted that 5 percent was still enough to keep the spammers in business.

Sophos has pointed out that many Valentine’s spam campaigns use graphics to bypass anti-spam filters that only scan text. This type of image spam was seen to increase by 100 percent during last year and Sophos sees it as being “one of the key spam trends during 2007”.