Main source of all Ransomware is pron.
Beware of pron.
How is “pron” pronounced?
Porn is not so much the case for getting these attacks. There are so many hackers out there that own mis-spelled domain names that look very similar to the home page. For example if you mispell freerepublic you could be sent to a page that drive by installs this junk. Even legitimate websites are pulling this trick now. How many times have you seen the “WARNING, your Adobe is out of date and needs to be updated.” I get that one if I visit Hotair and Townhall, both of which I have stopped visiting. A less experienced computer person will see these warning and click on “yes” or “install.”