- Police confiscate your laptop on some bogus pretext, then return it to you saying you're free to go.
- You open the laptop and find nothing that shouldn't be there. You wipe it, reinstall the OS and continue using the laptop.
- Surprise! The CPU now works for the police, so after some time it installs a rootkit or whatever.
Dunno if the microcode is big enough to do this kind of attacks, and perhaps some other firmware is easier to program.
But if someone waves this off saying that's not how police works in the US, well the world is larger than the US and it all definitely happens in other countries, only without CPU rootkits so far.
Situation without this CPU feature: Cops compromise the ME, disable Boot Guard, compromise your firmware, backdoor your OS directly
Situation with this CPU feature: Cops compromise the ME, disable Boot Guard, compromise your firmware, backdoor your CPU so it can later backdoor your OS
There's not really a meaningful difference between these! If there's an exploitable ME vulnerability then the police can absolutely own your system in an undetectable way regardless of whether or not this feature exists. If we were in a different universe where the ME enabled whether or not the CPU was in debug mode but wasn't responsible for any other security features then we'd care about this a great deal more, but as long as compromising the ME already gives you a way to permanently backdoor the system it's doesn't make any real difference.
- Police confiscate your laptop on some bogus pretext, then return it to you saying you're free to go.
- You open the laptop and find nothing that shouldn't be there. You wipe it, reinstall the OS and continue using the laptop.
- Surprise! The CPU now works for the police, so after some time it installs a rootkit or whatever.
Dunno if the microcode is big enough to do this kind of attacks, and perhaps some other firmware is easier to program.
But if someone waves this off saying that's not how police works in the US, well the world is larger than the US and it all definitely happens in other countries, only without CPU rootkits so far.