The pervasiveness of security-critical external resources (e.g accessories, online services) poses new challenges to Android security. In prior research we revealed that given the BLUETOOTH and BLUETOOTH_ADMIN permissions, a malicious app on an authorized phone gains unfettered access to any Bluetooth device (e.g., Blood Glucose meter, etc.). Here we further show that sensitive text messages from online banking services and social networks (account balance, password reset links, etc.) are completely exposed to any app with either the RECEIVE_SMS or the READ_SMS permission. Similar security risks are present in other channels (Internet, Audio and NFC) extensively used to connect the phone to assorted external devices or services. Fundamentally, the current permission-based Discretionary Access Control (DAC) and SEAndroid-based Mandatory Access Control (MAC) are too coarse-grained to protect those resources: whoever gets the permission to use a channel is automatically allowed to access all resources attached to it.
(2020). External resource control of mobile devices. US Patent: US10685142B2.