Cellular phones are no longer simple communications devices, but are usually miniature computers - Computer that could be susceptible to viruses. Traditional anti-virus companies like Symantec and McAfee already have AV products for mobile phones, and several other companies are hot on their heels. Two such companies, Massachusetts-based Kaspersky Labs and a Korean security firm AhnLab have announced plans to develop AV software for cellular phones running Symbian and Microsoft Mobile operating systems.

In the past two years, a few mobile phone viruses have appeared, most notably Cabir and commwarrior. The two viruses probably generated more press buzz than actually causing any damage. The Cabir virus appeared last year and was spread via a Bluetooth vulnerability on certain models of Nokia phones. It did not carry malicious payload, but it did drain phone batteries when it tried to spread. Commwarrior appeared in March of 2005 and was more of a nuisance. The virus would read the phone's address book and then spread via both Bluetooth and SMS messaging. Both of these viruses affected Symbian OS powered phones.

Most modern cellular phones are actually miniature PDAs powered by either the Symbian or Microsoft Mobile OS. Anti-virus giants McAfee and Symantec both have anti-virus software aimed at mobile users. McAfee's Virusscan Mobile is for Windows Smartphone powered phones, while Symantec's AntiVirus for Handhelds is made more for the PDA market.

Security companies are warning users that cellular phone viruses could cause even more damage than their desktop computer counterparts. In a forecast of upcoming threats, McAfee's AVERT labs predicts that mobile phone viruses will be, "a serious cause for concern", adding that the company expects to see a "significant rise" in mobile virus threats. McAfee also says that a large number of smartphones are currently unprotected by mobile security.

Why are companies so concerned? Simply becuae a phone is like a paperless rolodex, often containing names, email addresses and of course phone numbers. Blackberry phones are usually connected to either the telephone company's email server or more often an email server run by your employer. Phones also are generally trusted and we often will blindly accept a call, message or email from a friend's number or SMS address.