'but lately how are these drive-by installations happening? Mostly through holes in third-party software'
nope. by the user running an installer when requested by a browser ad popup.
nope. by the user running an installer when requested by a browser ad popup.
I agree that this is how most malware happens in general, but I was talking specifically about the subset of malware installations that are drive-by downloads, i.e. which are performed without user interaction:
http://en.wikipedia.org/wiki/Drive-by_download
What I mean to say is that most of those are exploiting third-party software (Java, Adobe Flash and Reader) rather than Microsoft stuff these days.