Being primarily Adware, is not terribly malicious in itself, but it certainly paves the way (or maybe even already opens a backdoor) for the more sinister of its ilk in the form of Key loggers, contact list harvesters & data ravaging viruses.
The reason why it's so dangerous is because it's almost invisible - being packaged with other legitimate apps like Facebook, WhatsApp and more (albeit only from third-party app sources, but still...)
How do you avoid this terror? Well, make sure that you only download Apps coming from the Google Play Store for one. Another more stringent set of steps you can take to make sure that you only install Googe signed Apps is to apply the following settings on your phone:
- Make sure that "Allow installation of Apps from Unknown Sources" is OFF
- Make sure that "Verify App Installations" is ON
Though the exact wording might be slightly different, both these settings are available under Settings > Security on your Android device...
Stay informed. Stay guarded.