To get this malware, you have to look on the internet, find it, and install it yourself on your Macintosh. You have to turn Gatekeeper off because the application doesn't come from the AppStore and isn't signed by the developer. You have to get past a few warning dialogs in MacOS X (like: Do you really want to install this application that comes from some untrusted site on the internet? Do you really, really want to run this application).
So it's not a virus, which would be software getting on your computer without you doing anything, it is a trojan where you have to go out of your way to install it yourself, turning off security features of MacOS X and ignoring multiple warnings.