Many Android devices come with pre-installed software. These apps cannot be uninstalled and they run with full system permissions. Consequently, they have a privileged position to access sensitive resources and information about each individual user and applications running on the device.

The openness of the Android operating system makes it possible for any handset manufacturer to ship a custom version of the system, along with proprietary pre-installed apps. As a result, any Android vendor can modify the Android firmware developed and maintained by Google.