Cryptojacking Apps Placed in the Microsoft App Store By Attackers

Security researchers found a cryptomining app in the Microsoft App Store. Researchers say that it was placed in the store between April and December 2018. It’s not clear how many users downloaded or installed the apps, but they had almost 1,900 user ratings.

However, the Symantec researchers believe the apps were created by a single person or group of attackers since they all share the same backend. The rogue applications posed as browsers, search engines, VPN, YouTube video downloaders and computer optimization tutorials and were uploaded by three developer accounts called DigiDream, 1clean, and Findoo.

the researchers said in a report “As soon as the apps are downloaded and launched, they fetch a coin-mining JavaScript library by triggering Google Tag Manager (GTM) in their domain servers.” “The mining script then gets activated and begins using the majority of the computer’s CPU cycles to mine Monero for the operators. Although these apps appear to provide privacy policies, there is no mention of coin mining on their descriptions on the app store.”

The app that works as a web page but also has access to the computer hardware through APIs, to send push notifications, use offline storage and behave a lot like a native program. The programs were published as Progressive Web Applications (PWA), these applications run independently from the browser, under a standalone process called WWAHost.exe.

When executed, the applications GTM, allows developers to dynamically inject JavaScript into their applications. It was noted that all the applications use the same unique GTM key, which proves that they were developed by the same group/individual.

The script loaded by the apps is a variant of Coinhive, a Web-based cryptocurrency miner that has been used in the past by attackers to infect websites and hijack visitors’ CPU resources.

Researchers informed the behavior of these apps to Microsoft and Google, and Microsoft removed the apps from their store. The mining JavaScript has also been removed from Google Tag Manager.

cryptocurrency mining remains of high interest to cybercriminals, and this incident only proves the case. Criminals have always been on the lookout for new ways to deploy coinminers, and what was the intention, whether it’s to hijack people’s personal computers or servers in datacenters, is still to be investigated.

Criminals have been trying to launch coinmining attacks through Android apps hosted on Google Play, through browser extensions for Google Chrome and regular desktop, Mozilla Firefox, through applications, through Windows 10 PWA, through compromised websites. There are also a variety of botnets that infect Linux and Windows servers with cryptocurrency mining programs by exploiting vulnerabilities in popular Web applications and platforms.

Users are advised to only download applications from trusted sources, whether on their mobile devices or computers. However, with rogue apps finding their place on official app stores, even that looks doubtful.