Security experts are warning PC users to be on guard against viruses masquerading as Valentine's Day messages, which could damage computers.
"Computer users should keep a wary eye on any romantic messages received by e-mail, as many of them could contain malicious code," said US security firm PandaLabs after detecting an increase in a worm it dubbed Nurech.A.
The worm hides in e-mails with subjects like: "Together You and I," "Til the End of Time Heart of Mine."
People who open an attached file such as postcard.exe can end up infecting their computers.
Security firm Symantec said it had detected "large-scale spamming" of e-mails including a Trojan horse, a program that contains or installs a malicious program.
Symantec said the malware was a new version of Trojan, Peacomm or the "Storm Trojan."
"With Valentine's Day approaching, this time around the authors are attempting to tug on the heartstrings of unsuspecting users with romantic subject lines such as 'My Heart belongs to you,' said Symantec's Orla Cox.
"The Trojan is much the same as we've seen before, the only difference being that the authors have used a modified packer in an (unsuccessful) effort to evade detection by antivirus vendors."
"As a general rule, don't open any suspicious e-mail, regardless of what is says it contains," said Luis Corrons, technical director of PandaLabs.
"Instead of going on instincts, let a security solution decide whether it's safe to open it or not," he said, urging users to scan any suspicious messages with an antivirus program.
Corrons said events like Valentine's Day and Christmas are often exploited by cyber-criminals to try and spread their creations by disguising infected e-mails as e-greeting cards.
This use of "social engineering" was used in the LoveLetter virus, which caused one of the biggest epidemics in computer history.
Copyright © 2007 Agence France Presse.