That mobile phone to your ear is rapidly becoming one of hackers' favorite targets, researchers said this week.

In separate reports, two security firms reported that vulnerabilities in emerging mobile and cellular technologies -- combined with the increasing ubiquity of the devices across the globe -- are making the wireless phone a more attractive target than ever.

McAfee's Avert Labs research unit today will release its Sage threat analysis, which predicts that the number of mobile malware attacks targeted at smartphones and wireless PDAs will double by the end of this year. "The threat here is very real," says David Marcus, security research and communications manager at McAfee Avert Labs.

That view is supported by other malware research firms. Sipera, which specializes in mobile security technology, reported last week that it has discovered a number of vulnerabilities in dual-mode cellular and WiFi phone systems.

"Just like what's happening to PCs, the same thing can happen to these phones," says Krishna Kurapati, CTO of Sipera.

Mobile and cellular phones are becoming a way of life for most of the world, with about 2.7 billion subscriptions currently active, according to the McAfee Avert Labs report. "Countries like Japan are 10 years ahead of the U.S. in their use of mobile phone technology," Marcus says. "They routinely use their phones for financial transactions, which makes them an attractive target for hackers."

And although there are many different carrier technologies for wireless phones around the world, most of them use the Symbian operating system, which means that a single hack can go a long way. "It's like Windows," Marcus says. "It's the dominant OS, so it's an obvious target."

McAfee Avert Labs predicts that most of the initial growth in mobile phone malware will take the form of adware or spyware, such as SymbOS/Mobispy -- designed to track users' activity or lure them onto Websites or online services. "We're also seeing some voice-based spam, where a caller uses voice or voicemail to social-engineer the user over to a Website," Marcus says.

But according to Sipera's report, attackers already are going beyond simple spyware. The company's Viper Lab research unit reported last week that dual-mode devices -- the popular smartphones and PDAs that can switch back and forth between cellular and WiFi networks -- have already been penetrated. Among the vulnerabilities reported by Sipera:

McAfee Avert Labs also has discovered several malicious programs for smartphones, including J2ME/RedBrowser, that send text messages to costly premium-rate service numbers without alerting the user, essentially running up the user's bill. Such attacks can cause users to change carriers in a hurry, so mobile service operators are beginning to take a hard look at emerging threats, the Sage report says.

Compared to PC attacks and malware, mobile phone exploits are "practically a flat line," Marcus concedes. "But attackers will move quickly to any venue that has the user base and kinds of transactions we are seeing emerge in the mobile device space. With the vulnerabilities out there, we can expect the threat to grow very rapidly."— Tim Wilson, Site Editor, Dark Reading