Antivirus company Doctor Web has identified spyware in over 100 Android applications that had more that 421 million cumulative downloads in Google Play.
The malicious module, which Doctor Web named ‘SpinOk’, is distributed as a marketing SDK. On victims’ devices, it can collect information about files, can send files to the attackers, and can steal clipboard content.
The SpinOk module offers mini games, tasks, and alleged prizes to maintain users’ interest in the applications.
Upon execution, the SDK connects to the command-and-control (C&C) server and sends a trove of device information, including data from sensors, which allows it to detect emulator environments. The server response contains a lot of URLs used to display advertising banners via WebView.
Additionally, the module can collect a list of files in specified directories, check for the presence of specific files and directories, upload files from the device, and copy or substitute clipboard content.
“This allows the trojan module’s operators to obtain confidential information and files from a user’s device—for example, files that can be accessed by apps with Android.Spy.SpinOk built into them. For this, the attackers would need to add the corresponding code into the HTML page of the advertisement banner,” Doctor Web explains.
The malicious module and modifications were identified in a total of 101 applications in Google Play. Google has been notified and has removed some of the apps. In some cases, only certain versions contained the malicious SDK.
Some of the most popular applications containing the malicious module include Noizz (over 100 million installations), Zapya (over 100 million installations – the code was present in versions 6.3.3 to 6.4), VFly (over 50 million downloads), MVBit (more than 50 million installations), and Biugo (over 50 million downloads). Doctor Web has published a full list of infected applications.