Mobile phone capabilities are growing by leaps and bounds — and so are mobile security threats.

Ten years ago, mobile phone subscribers and operators only had to worry about two security threats: eavesdropping and fraud. Most cell phones operated on reallocated UHF-TV channels using conventional FM radio technology. It was ridiculously easy (though illegal) to tap conversations and pluck phone identities off the air to make free international calls. Fraud was a huge problem for cell phone operators.

Those problems largely dissipated as the industry converted to digital radio technology. The 3G technologies being deployed today by AT&T (formerly Cingular Wireless) and Verizon Wireless make hacking cell phones over the air even more difficult and expensive.

Unfortunately, as mobile phones become more capable, a constellation of new security threats have emerged.

A growing percentage of mobile phones can download user applications and content over the air. That means they can also download viruses and spyware. Bluetooth is becoming a standard feature on mobile phones, and handsets with Wi-Fi capability are on the way. These short-range radio technologies are a potential backdoor for harmful code. Flash memory cards create another entrance to phones that used to have no windows or doors.

According to SMobile Systems, a company specializing in mobile security, there are more than 400 mobile malware threats, predicted to exceed 1,000 by the year-end. Most are viruses, but mobile spyware is on the rise.

New security-related concerns are popping up. Some operators can track the user’s movements. However, this is mainly done with GPS-equipped handsets; the user is only automatically located when calling E911. There also is the specter of users accessing pornography in public. Camera phones are a recognized security threat at many business and government locations. Finally, with today’s high-capacity flash memory cards, cell phones could become vehicles for unauthorized distribution of copyrighted content.

What can be done about the mobile security threats?

There are several ways to thwart delivery of viruses, spyware and pornographic content to mobile phones. One method is to detect and block unwanted content in the mobile operator’s core network before it gets to the user’s handset. Companies such as Starent Networks produce packet data serving nodes that can use deep packet inspection to detect and remove security threats and unwanted content.