A research group has released a paper <http://www.theregister.co.uk/2016/08/05/payperinstall_study/> studying those “free” software installs that bring along a host of uninvited guests with them. While not actually illegal (yet), they resort to sneaky tactics, like lying low for a few weeks before taking over your browser search bar or injecting ads, to try to obscure their origin. They even actively defeat blocking attempts, by jumping between domain names as often as in a matter of hours.