DroidDream turns Androids into zombies

Further analysis finds that the 50 malicious applications removed from the Android Marketplace include dropper functionality.

The malicious code that led Google to remove more than 50 Trojan applications from the Android Marketplace appears to mainly be a "dropper" -- a program designed to load other code to further compromise the affected smartphone, according to a security firm's analysis.

The code, dubbed "DroidDream," attempts to use two exploits to gain root privilege on a compromised smartphone by breaking out of the sandbox designed to limit what applications can do on Android devices, mobile security firm Lookout stated in its most recent analysis. While the vulnerabilities targeted by the program were patched by Google last year, the majority of phones do not have the update yet, allowing the attack to compromise more than 260,000 phones, Google said in a statement.

Also see: After attacks, Google vows to fortify Android Market

Following the first stage of the attack, the program then forwards phone-specific information -- including hardware, software and service identifiers -- to a command-and-control server, which can then direct the compromised phone to reconnect at a certain time and download additional functionality from a specific URL, according to Lookout's analysis.

"The second stage is more interesting -- it is essentially a blank check," says Kevin Mahaffey, Lookout co-founder and chief technology officer.

The second-stage program appears to have unfinished functionality that would have allowed it to manipulate Marketplace ratings and post comments, the Lookout analysis states, concluding that "DroidDream could be considered a powerful zombie agent."

Google pulled down 58 applications from the Android Marketplace and has started to identify affected users and remotely remove the malicious applications from their smartphones. The company will also be pushing a security update to all users to undo any malicious changes and augmenting security measures for the Android Marketplace to attempt to head off future incidents, the company stated in a blog post.

Security companies have repeatedly predicted the rise of mobile malware, but the threat has typically been more myth than reality. Previous attacks against Android-based smartphones have targeted non-Marketplace apps. Earlier this year, for example, Lookout warned of the Geinimi Trojan, which mainly spread in China.

Yet, malware developers seems to be focusing more intensely on mobile-device users. Businesses need to worry because their IT departments do not have the same control over smartphones that they may have over their PCs and laptops, Mahaffey says.

"When there is a vulnerability there are two choices: You can work around it or you can patch it," he says. "With mobile, there really isn't that ability (to patch) right now."

Instead, businesses should deploy device management software that allows them to implement application whitelists, he says.

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