The Coolpad 1851 Android device with a build fingerprint of Coolpad/android/android:8.1.0/O11019/1534834761:userdebug/release-keys contains a pre-installed app with a package name of com.mediatek.wfo.impl app (versionCode=27, versionName=8.1.0) that allows any app co-located on the device to modify a system property through an exported interface without proper authorization.