Security researchers have uncovered a trojanized adware family that has the capability to automatically install any app on an Android device by abusing the operating system’s accessibility features. The Shedun app tricks users into granting them access to the Android Accessibility Service. Shedun apps can’t be easily uninstalled, as the apps root the victim’s device and then embed themselves in the system partition in an effort to persist even after factory reset. All the three adware families root-infect Android devices in order to prevent their removal and give attackers unrestricted access to devices.
Source: https://thehackernews.com/2015/11/android-malware-auto-install.html