Malware ridden executables are distributed via torrent websites and promise to deliver cracked versions of software. Malware is compiled as Windows EXE binaries with the help of the open source Mono framework. Mono is designed to allow developers to create cross-platform applications part of the.NET Foundation, which can be later used on multiple platforms, from. macOS, Windows, Android, most Linux distributions, BSD, and Solaris, as well as some game consoles such as PlayStation, Xbox, and Wii.
Source: https://www.bleepingcomputer.com/news/security/windows-malware-runs-on-macs-bypasses-gatekeeper-to-target-software-pirates/