SAN DIEGO -- With the Valentine's Day holiday approaching, the San Diego office of the FBI warns computer users to be on the lookout for spam e-mails that are spreading malware known as "Storm Ware."

According to an FBI news release, the e-mail directs recipients to click on a link to retrieve an electronic greeting card.

Once the user clicks on the link, malware is downloaded to the user's computer, causing it to become infected and become part of the Storm Ware botnet, authorities said.

A botnet is a network of compromised computers under the control of a single hacker. Botnets can be used to facilitate criminal activity such as sending spam e-mail, identity theft, denial of service attacks and spreading malware to other computers connected to the Internet, the FBI news release said.

The Storm Ware malware has capitalized on various holidays in the past year by sending millions of e-mails advertising an electronic greeting card link in spam e-mail. Valentine's Day has been identified by the FBI as the next target.

Authorities warn computer users to be wary of any e-mail received from an unknown sender. Experts recommend computer users never open any unsolicited e-mail or click on any links provided in them.

If computer users receive such e-mail, the news release suggests the recipient file a complaint at http://www.ic3.gov.