A recent rise in Android malware—combined with increased efforts to combat the threat—highlight the fact that, just like tech companies, app makers, and users, hackers are fast turning their attention to mobile devices. What's more, experts say, such devices are often configured in ways that make it easier for malware to thrive.

Several new types of Android malware have been spotted "in the wild" in recent weeks, and they demonstrate growing sophistication. One specimen, dubbed Opfake, is a bogus Web browser that automatically makes calls to premium phone lines. Opfake exhibits a powerful trick previously seen only in desktop malware, whereby the code repeatedly mutates to make anti-virus detection more difficult.

To counter the rising tide of threats, Google last week announced it had launched an app prescreening tool called Bouncer that runs a server-based simulation to check apps for malicious behavior—such as attempts to access or send personal data, or simply send out pricey text messages. Google blocks them before they get into the official Android Market.