AndroidOS/MalLocker.B Ransomware

Overview

Microsoft has recently discovered a new variant of ransomware with novel techniques and behavior on Android devices. The malware, known as AndroidOS/MalLocker.B, is the latest variant of an existing family that is widely used and distributed across online forums, apps, and more. The primary way attackers lure victims in is by leveraging social engineering within these platforms.

The ransomware will lock the device and display a ransom note on the home screen. This variant leverages new tactics to circumvent prevention measures put in place by Google that were meant to block creation of an overlay window that could not be dismissed by the user. It appears that there are machine learning capabilities that will enable this malware family to constantly evolve in the future.

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Lookout Analysis

In the past, ransomware messages like this one persisted through an infinite loop of creating (drawing) and recreating (re-drawing) the overlay screen. Between the draw and re-draw, it was possible for users to get to their apps and uninstall the malicious app. This latest variant is able to create an infinite loop that avoids that draw and re-draw process that makes it impossible for the user to be able to access the device and remove the offending app.