Researchers have spotted the first malware that exploits a critical vulnerability in Android 2.3, aka Gingerbread, finding samples tucked into legitimate apps on Chinese download sites.
Earlier threats aimed at Google's Android, including the widely-distributed DroidDream and DroidDream Light, exploited bugs in older versions of the mobile operating system but were not able to hijack Gingerbread-powered smartphones.
Last Thursday, Xuxian Jiang, an assistant professor in computer science at North Carolina State University, said that his team and Beijing-based NetQin Mobile Security had identified new "high-risk" malware that can root, or completely compromise, Android 2.3.
Jiang named the malware "GingerMaster."
GingerMaster utilizes the "GingerBreak" exploit first unveiled in April, when attack code was published on the Internet, said Jiang in a blog post.
Like most Android malware, GingerMaster hides inside legitimate Android applications that attackers have pirated, added malware to, then re-released onto popular download markets.
When unsuspecting users download the infected apps, the exploit kicks into action, "rooting" the smartphone to gain complete access, harvesting personal data from the phone, including the device ID and the phone number, before sending that to a command-and-control (C&C) server maintained by the attackers.
The malware waits for further instructions from the C&C server, which can tell jacked phones to download even more malware or other apps, said Jiang.
Vanja Svajcer, a principal virus researcher with U.K.-based Sophos, confirmed Jiang's findings after uncovering a GingerMaster sample in an app that shows photos of celebrities, including Lady Gaga.
In a post to the Sophos security blog Monday, Svajcer said he had downloaded the infected app from a Chinese-language site that caters to Android owners.
Although some infected apps have slipped into Google's official Android Market, a larger number are distributed through alternate sites, including several popular Chinese app marts.
Last month, for instance, Jiang warned Android users of a then-new threat, called "HippoSMS," that his group had found on unauthorized Chinese app stores.
And in multiple campaigns this year, attackers have planted infected apps on the Android Market, forcing Google to yank more than 50 applications from the store in March and another 30 in late May.
According to several antivirus vendors, the volume of Android malware has jumped this year.
Earlier this month, San Francisco-based Lookout Security said that the likelihood of an Android owner encountering malware shot up two-and-a-half times in the first six months of 2011.
Today, McAfee added its voice to the chorus about a rising tide of Android malware, saying in a new report ( download PDF ) that hackers had pushed Android into their No. 1 target by crafting more threats against that mobile OS than any other.
NC State's Jiang stressed that the newest Android malware is a significant threat, and urged smartphone owners to watch where they download apps and remain vigilant when an app requests a large number of permissions.
"Due to the fact that GingerMaster contains the most recent root exploit, we consider it poses one of the most serious threats to mobile users," Jiang said.
Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, on Google+ or subscribe to Gregg's RSS feed. His e-mail address is gkeizer@computerworld.com.
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