(I did, of course install the Apple Update for OS and for Java (but not for iTunes, Remote Access Users [!} and such as I don't use anyway.)
But Java's still turned off--via Occam: A couple mouse clicks can turn it on, should I see an item I might want to pursue, [not responding] on a site that doesn't scream, HaxxorsHaven-WelcomeKiddies.
I've become well Aware, after these years Here, of the vast gulf 'twixt my merely somewhat-informed er, logical deductions and er, Logic:the Professional's Game.

Under "..there are Known unknowns and Unknown unknowns" (from that entertaining former SecDef guy and his fanciful musings", I hope I have stored a small toolkit of
Don't!!s// Maybes..IF ... and ... // and, dunno WTF to Do? about *this* oddity.

And I cannot remotely comprehend how it IS that Greg maintains such an encyclopedic Recall of near-infinite details, across so many OS-peculiarities nor
--since 'Vincents' and 'accelerators'
--have I aimed to build my demi-version of such a massive amount of lore: All Earned by n-mistakes, tip by tip.

I walk both sides/of street:

1) Resignation, as crazy suggests--and even IF you strongly suspect that Pwnership has occurred [and did it also ~brick even Time Machine's hallowed real Backups, hmm??]
I Won't Find its mechanism, ever.

2) So I be careful, have no interest in random investigations of the millions of idiot-sites:
What was the estimated total life of The Cosmos until Heat-Death, lately? How much of that does one want to squander, reading pap?

3) Had I more $$ for Communication-with-other-Entities, based on all the options I recall since Info World was an almost-decent Tech News Rag:
I'd have duplicate iMacs, one always Off-web, probably [with advice] some means of mirroring, but delayed: so that, following a few basic Tests of OS operation since Last Test:
Then: go ahead and duplicate the (still-OK. probably.) main unit.
This is not infallible, for reasons of all caveats mentioned here and elsewhere.
(If $Rich: a third machine, never On-line, to which only my data files are periodically xferred via some least-risky algorithm + hunches?)

In the end though, I believe I share with some here, a disbelief in Perfection or in Certainty, so ... if the Cosmos elects to skewer me with a Maxwell's Demon Event?
[I wonder re. HEAT in the New! Insanely-thin iMacs, and whether smcFanControl can still attain *my* idea of OK temps inside, should I need a 2-yr. old 21.5"er..]

Bring it ON, Mofos!--you Aren't fooling Moi: I KNOW It's All a Stage/I a mere Player, etc.

(It's Today--and iMac is still running pretty fast, for 90+ tabs open.)