Resource-draining currency miners are a regular part of the Google Play market, as scammers pump out apps that covertly harness millions of devices, in some cases with malware so aggressive it can physically damage phones. A popular title in the Mac App Store recently embraced coin mining openly, and so far Apple gatekeepers haven't blocked it.
The app is Calendar 2, a scheduling app that aims to include more features than the Calendar app that Apple bundles with macOS. In recent days, Calendar 2 developer Qbix endowed it with code that mines the digital coin known as Monero. The xmr-stack miner isn't supposed to run unless users specifically approve it in a dialog that says the mining will be in exchange for turning on a set of premium features. If users approve the arrangement, the miner will then run. Users can bypass this default action by selecting an option to keep the premium features turned off or to pay a fee to turn on the premium features.