Overview
An issue was discovered on BLU R1 HD devices with Shanghai Adups software. The content provider named com.adups.fota.sysoper.provider.InfoProvider in the app with a package name of com.adups.fota.sysoper allows any app on the device to read, write, and delete files as the system user. In the com.adups.fota.sysoper app's AndroidManifest.xml file, it sets the android:sharedUserId attribute to a value of android.uid.system which makes it execute as the system user, which is a very privileged user on the device. This allows a third-party app to read, write, and delete files owned by the system user. The third-party app can modify the /data/system/users/0/settings_secure.xml file to add an app as a notification listener to be able to receive the text of notifications as they are received on the device. This also allows the /data/system/users/0/accounts.db to be read which contains authentication tokens for various accounts on the device. The third-party app can obtain privileged information and also modify files to obtain more privileges on the device.