New Gustuff Android Trojan Capable of Targeting More Than 100 Banking Apps

Researchers detected a new Android Trojan called Gustuff that is capable of targeting more than 100 mobile banking apps.

Group-IB discovered that Gustuff infects Android smartphones via SMS messages that contain links to malicious Android Package (APK) files. Once infection is complete, the malware abuses Accessibility Service to leverage its Automatic Transfer Systems feature on an infected device. This capability enables the Android Trojan to bypass security mechanisms when a victim interacts with any of more than 100 banking apps, as well as online stores, payment systems and cryptocurrency services.

Specifically, Gustuff uses fake push notification to steal users’ payment credentials or personal details. It can then potentially use the Accessibility Service to automatically fill payment fields for illicit transactions. At the same time, Gustuff is capable of sending sensitive information about the infected device to its command-and-control (C&C) sever, reading/sending SMS messages and resetting the device to factory settings.

Abusers of Android’s Accessibility Service

There is a history of malware abusing Accessibility Service, a feature designed to assist users with disabilities in their interactions with Android devices. Back in July 2017, for instance, Kaspersky Lab observed a Trojan misusing the Android service to gain access to the user interface (UI) of other apps and then steal banking-related information. In December 2018, researchers at ESET discovered a family of malware leveraging Accessibility Service to target users of the Android PayPal app.

These findings come amid a rising prevalence of banking Trojans in general. Over the course of 2018, Kaspersky Lab observed the number of Android users who suffered a banking malware infection more than triple to 1,799,891. These infections took place around the world, though users living in Russia, South Africa and the U.S. were most often affected.

How to Protect Your Organization From Android Trojan Attacks

Security professionals can help defend their organizations from an Android Trojan like Gustuff by training all employees on how to best protect sensitive information, including any data stored on mobile devices. This means enforcing strong password policies and teaching all users, including executives, about what these requirements entail.

Additionally, organizations should enforce layered security controls such as multifactor authentication throughout the workplace and for remote workers.

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David Bisson

Contributing Editor

David Bisson is an infosec news junkie and security journalist. He works as Contributing Editor for Graham Cluley...