CVE-2019-15349: Tecno Camon device lets any app run as system

The Tecno Camon Android device with a build fingerprint of TECNO/H612/TECNO-ID5a:8.1.0/O11019/F-180828V106:user/release-keys contains a pre-installed platform app with a package name of com.lovelyfont.defcontainer (versionCode=7, versionName=7.0.11). This app contains an exported service named com.lovelyfont.manager.service.FunctionService that allows any app co-located on the device to supply the file path to a Dalvik Executable (DEX) file which it will dynamically load within its own process and execute in with its own system privileges. This app cannot be disabled by the user and the attack can be performed by a zero-permission app. Executing commands as the system user can allow a third-party app to video record the user's screen, factory reset the device, obtain the user's notifications, read the logcat logs, inject events in the Graphical User Interface (GUI), and obtains the user's text messages, and more. Executing code as the system user can allow a third-party app to factory reset the device, obtain the user's Wi-Fi passwords, obtain the user's notifications, read the logcat logs, inject events in the GUI, change the default Input Method Editor (IME) (e.g., keyboard) with one contained within the attacking app that contains keylogging functionality, and obtains the user's text messages, and more.