Thirteen apps removed from the Google Play Store were part of a malware chain called Brain Test. The apps looked harmless to users and to the Android operating system itself, but were poised to do terrible things. These malicious apps would get installed on an Android device where they would attempt to gain root access. These apps also helped install other malware infected apps on the same device, unbeknownst to the owner of the phone. Because the original 13 apps were games that some found fun to play, it was easy for them to find Android users to install them.
These infected apps were able to create phony reviews on the Google Play Store, enticing other Android users to install them. And with rooted phones, even a factory reset wouldn't remove them. In that case, users would have to flash a clean build of Android from a Factory Image onto their phones. At the time detected, these apps were in the process of installing other infected apps on various units. Had they not been spotted, the damage to infected handsets could have been immense.
The chart at the top of this article lists the 13 apps that were kicked out of the Google Play Store. Make sure none of them are installed on your phone. The motive, by the way, is money. The hackers behind Brain Trust sell a guaranteed number of app installations to developers. By creating the malware, these hackers can meet their promises to these developers, earning them big bucks. Some of the apps had 500,000 installations or more, with a (bogus) 4.5 rating.
source: Lookout via RedmondPie