Fascinating, tacit, as is your Intuit article; many thanks for making all of us more aware of the dangers lurking on the Internet!
(I'll mention, though, that I've used TurboTax on-line for a number of years [although I've never visited any of Intuit's related websites] with no repercussions.)
Just to be certain, though, which, if any, of your three "how-they-do-its" is vulnerable to an Apple Security Update?