Code injection

The Sony keyaki_kddi Android device with a build fingerprint of Sony/keyaki_kddi/keyaki_kddi:7.1.1/TONE3-3.0.0-KDDI-170517-0326/1:user/dev-keys contains a pre-installed app with a package name of com.kddi.android.packageinstaller app (versionCode=70008, versionName=08.10.03) that allows other pre-installed apps to perform app installation via an accessible app component. This capability can be accessed by any pre-installed app on the device which can obtain signatureOrSystem permissions that are required by other other pre-installed apps that exported their capabilities to other pre-installed app.