3 ms·
well, I guess it depends on how the private key is stored in the CPU, how if any data they can inject or cause the CPU (via power rail noise/whatever) to accept
by StillBored 4y ago
well, I guess it depends on how the private key is stored in the CPU, how if any data they can inject or cause the CPU (via power rail noise/whatever) to accept an update/etc which allows the private key/or validation routine to be bypassed.
Basically, the easier route is usually to just find a way to bypass the check once, and use that to install a more permanent bypass.
- aaronmdjones 4y agoThe key in your CPU would be the public key, not the private key. The public key can only be used to verify existing signatures, not create new ones. It may be possible through power fault injection to flip the bits of the public key such that you could get it to accept microcode signed with your own private key, but I would be very surprised if the public key weren't burned into the structure of the CPU itself in a manner that renders it immune to such attacks. Of course, power fault injection may still allow you to bypass the verification routine altogether instead of modifying the key it verifies with.
- StillBored 4y agoAgree on the public/private thing, I typed without my brain in gear.