The popularity of smart phones is growing at a breakneck speed, raising concerns over cell phone viruses.

Cell phone viruses first broke onto the scene in 2005 when hackers learned how to utilize Nokia's Symbian Series 60 phone's text messaging system.

When a user of this phone received a text infected with the virus, the virus harvested the phone's list of contacts and forwarded itself to everyone in the user's address book. The receiving phones got an alluring text message reading, 3DGame from me. It is FREE!

If the recipients downloaded what they thought was the game, the virus forwarded itself to their contacts, and so on.

Cell phone technology has come a long way since then, but with the rapidly increasing use of smart phones comes a new breed of viruses. Some of these viruses are Trojans, which are programs that pretend to be something else such as a free game in order to trick the user into installing them.

"Smart phone viruses are relatively limited, but as smart phones such as the iPhone continue to penetrate the U.S. market, the number of viruses can be expected to increase," Tim Deluca-Smith, vice president of marketing at WDSGlobal, told Life's Little Mysteries.

In 2009, a smart phone virus hijacked users' Facebook passwords when they updated their statuses through their phones. The virus then posted status updates reading, "I'm 8 1/2 pounds lighter thanks to the FREE trial pack of this new colon cleanser that I got! visit ExpressColon.net to get yours!"

Bluetooth technology, which sends messages wirelessly over short distances, has also made it easier for viruses to spread. For instance, a phone infected with the Cabir virus uses Bluetooth to seek out other cell phones within about 100 feet (30 meters). Then, disguising itself as a security file, it sends itself to every vulnerable device in range and, once installed, drains the phones' batteries as it starts a new Bluetooth scan.

"People often put viruses in other people's devices to steal personal information," said Martin Libicki, a senior policy analyst at the Rand Corporation and who specializes in e-commerce and technology security. As more people use their phones to make online purchases for example, by buying movie tickets while on the way to the theater more viruses will be developed to snatch personal data such as bank account information and credit card numbers, Libicki said.

"As credit card transactions become more commonly used over time, cell phones should be updated with software that is more resistant to virus technology," Libicki said.