Android 7.1 Nougat contains a secret panic mode designed to be triggered in the event that malware locks a user's screen.
The new feature called “panic detection” actively listens for multiple presses of the back button and automatically overrides whatever is on the screen to return a user to the home screen when it detects a user pressing the button four consecutive times in a row, according to an xda-developers July 10 blog post.
Researchers warn the feature may have been kept secret to both prevent attackers from attempting to compensate for the feature and to discourage users from developing a false sense of security that might leave them prone to more careless action.
A user is still responsible for deleting any potentially malicious apps once returned to the home screen as the malicious apps could still perform other harmful behaviors. Its also worth noting that just because a user has Android 7.1 Nougat installed doesn't mean the panic detection behavior is actually enabled and the researchers did not disclose how to enable the feature outside of editing their devices source code.