Can you explain what this means?

With physical access to a machine’s USB 3 port, someone could insert running code beneith the operating system, and it wouldn’t know.

You could spy on user activity, sniff encryption keys etc

As well as physical access do you also need to set a bios setting? It isn't entirely clear to me but the background information article linked in this thread seems to suggest yes.

Sorry, I’m not sure, this stuff largely goes over my head. I just understand the basics.

If I had to guess, I wouldn’t be surprised if a different exploit is found that bypasses the bios setting to compliment this one.

Full control over the Intel backdoor / remote administration engine that's on all their modern CPUs. (It may not be an intentional backdoor, but it's certainly looking as if it's been usable as one by intelligence agencies.)

OK so the implication being that with this thing found, someone could make a USB device that when plugged into an intel machine immediately gets control?

Precisely so. At least for the Intel machines that have IME features. So all the enterprise, data-center boxes but not every laptop.

Edit: I read some more. It looks like this is going beyond what I thought and affects way more machines.

Reading http://www2.lauterbach.com/pdf/dci_intel_user.pdf, there are two ways to debug over that connector; one using the USB protocol and the other using a proprietary protocol. If this uses the latter, that device, technically, wouldn’t have to be a USB device (but of course, it could still masquerade as one)

That PDF also says your BIOS must support this kind of debugging, and, for the ‘OOB’ protocol, your hardware must support it. So, your BIOS may be configurable to make this attack impossible, and your hardware may already be protected against it.

Then you simply have to replace the bios with one that has USB debugging enabled. Or change registers on a working machine

‘Simply’ may mean entering, possibly cracking, the BIOS password (hm, are there BIOSes that use two-factor authentication?). It also means you can’t simply plug in a USB device.

i mean to resolder the flash chip that holds it

As long as I know, is not in 'all' their modern CPUs. Just all the CPUs with vPro feature, that aren't the ones used in domestical environments but large businesses.

You're talking about AMT (which runs on the Intel ME - Management Engine). The ME itself, however, is on every CPU (running Minix on Skylake and later CPUs, ThreadX on earlier models), because one of the responsibilities of the ME, apart from being a backdoor, is to manage the CPU: power it on, handle power signals, etc. The CPU wouldn't run without the ME, so it's necessary that it's on all CPUs.

Given what we know of the NSA's past predation, why would one think this is not intentional?

Intels own guidelines say that DCI should be disabled by default, although on some systems that was not true[1], afaik (would like to be corrected if wrong) this does not impact vast majority of systems. This seems more like a frontdoor that is supposed to be locked tight rather than an backdoor. The bugs that actually enable DCI could be more likely candidates to be considered backdoors.

[1] https://security-center.intel.com/advisory.aspx?intelid=INTE...

But once that front door is open, people will be able to walk around in the house and figure out how to 1) finally disable the thing for good, or 2) find a more universal attack that doesn't use that door.

This link is broken.

They probably removed the languageid parameter, thinking it was optional.

https://security-center.intel.com/advisory.aspx?intelid=INTE...

Excellent, where can I trade in my ducky for this upgraded version?

All your CPU are belong to us