Many Macs (and PCs) are vulnerable to this threat

[Ron]

Even if you are diligent about keeping your S/W up to date and run the best threat protection software you are still likely vulnerable:

" ......  In other words, sophisticated hackers today have moved beyond the average user's simplified picture of a computer: applications on top of an operating system on top of hardware. Instead, they're inserting themselves into the hidden corners of a computer's architecture that exist outside that picture. And anyone hoping to keep their computer truly secure will need to start looking into those corners, too.

The full article is here:  https://www.wired.com/story/critical-efi-code-in-millions-of-macs-is-not-getting-apple-updates?mbid=nl_092917_daily&CNDID=%%CUST_ID%%