It is very easy to avoid. Don’t allow adult sites to install APKs on your device and you will be fine. While I question the choice of a smartphone for this type of activity anyway, you really have to unlock the door, hand the bad guys your key, and make them some tea after you invite them in to do what they will. To have this installed you have to (1) visit the site, (2) allow installation of apps from unknown sources in your settings menu, and (3) MANUALLY install the APK. If you don’t do any one of these three things, there is zero chance of you being affected. This is really a non-issue for almost everyone.