A group of researchers conducted an interesting study on AT commands attacks on modern Android devices discovering that models of 11 vendors are at risk. The research revealed that millions of mobile devices from eleven smartphone vendors are vulnerable to attacks carried out using AT commands. AT commands are a set of short text strings that can be combined to perform a series for operations on mobile devices, including dialing, hanging up, and changing the parameters of the connection. In many cases, using the custom AT commands it was possible to access very dangerous features implemented by the vendors.”]
Source: https://securityaffairs.co/wordpress/75683/hacking/at-commands-attacks-android.html