The FBI is warning computer users to watch out for Valentine's Day electronic greeting cards that may contain malicious software known as 'Storm Worm.'
The email directs the recipient to click on a link to receive the e-card.
Once the user clicks the link, malicious software (malware) is downloaded to the computer, causing it to become infected.
The computer then becomes part of the Storm Worm botnet -- a network of compromised machines under the control of a single user, the FBI said in a press release.
Botnets are generally set up to facilitate criminal activity such as spam email, identity theft, denial of service attacks and spreading malware to other machines on the Internet, said the FBI.
In the past, the Storm Worm virus has used various holidays to get recipients to click on unsolicited emails.
In January, spammers exploited the public's interest in a European storm to spread the virus.
The emails' subject line was "230 dead as storm batters Europe."
At that time, security experts said the malware had infected at least 10,000 PCs worldwide.
The FBI warns computer users to be wary of any email received from an unknown sender.
If you have received a Storm Worm email you can file a complaint at .
