Check Point Research (CPR) has discovered a new and innovative malicious threat on the Google Play app store which spreads itself via mobile users’ WhatsApp conversations, and can also send further malicious content via automated replies to incoming WhatsApp messages.
By replying to incoming WhatsApp messages with a payload from a command-and-control (C&C) server, this method could enable a hacker to distribute phishing attacks, spread further malware, or spread false information or steal credentials and data from users’ WhatsApp account and conversations .
Researchers discovered the new and innovative malicious threat on the Google Play app store which spreads itself via mobile users’ WhatsApp conversations, and can also send further malicious content via automated replies to incoming WhatsApp messages.
They found the malware hidden within an app on Google Play called “FlixOnline”.The app is a fake service that claims to allow users to view Netflix content from all around the world on their mobiles.
However, instead of allowing the mobile user to view Netflix content, the application is actually designed to monitor the user’s WhatsApp notifications, and to send automatic replies to the user’s incoming messages using content that it receives from a remote command and control (C&C) server.
The malware sends the following response to its victims, luring them with the offer of a free Netflix service: “2 Months of Netflix Premium Free at no cost For REASON OF QUARANTINE (CORONA VIRUS)* Get 2 Months of Netflix Premium Free anywhere in the world for 60 days. Get it now HERE.”
Using this technique, a threat actor could perform a wide range of malicious activities:
* Spread further malware via malicious links;
* Stealing data from users’ WhatsApp accounts; and
* Spreading fake or malicious messages to users’ WhatsApp contacts and groups (for example, work-related groups).
How the malware works
When the application is downloaded from the Play Store and installed, the malware starts a service that requests ‘Overlay’, ‘Battery Optimization Ignore’, and ‘Notification’ permissions. The purpose behind obtaining these permissions is:
* Overlay allows a malicious application to create new windows on top of other applications. This is usually requested by malware to create a fake “Login” screen for other apps, with the aim of stealing victim’s credentials.
* Ignore Battery Optimisations stops the malware from being shut down by the device’s battery optimisation routine, even after it is idle for an extended period.
* The most prominent permission is the Notification access, more specifically, the Notification Listener service. Once enabled, this permission provides the malware with access to all notifications related to messages sent to the device, and the ability to automatically perform designated actions such as “dismiss” and “reply” to messages received on the device.
If these permissions are granted, the malware then has everything it needs to start distributing its malicious payloads, and responding to incoming WhatsApp messages with auto-generated replies. Theoretically, though these auto-generated replies, a hacker can steal data, cause business interruptions on work related chat groups, and even extortion by sending sensitive data to all the users contacts.
CPR responsibly notified Google about the malicious application and the details of its research, and Google quickly removed the application from the Play Store. Over the course of two months, the “FlixOnline” app had been downloaded approximately 500 times.
• Research by: Aviran Hazum, Bodgan Melnykov and Israel Wenik, from Check Point Research