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Yes to AMD, not to Apple. There is no secret core on Apple chips that has control over the system. They are much better designed than AMD/Intel CPUs and strictl

Yes to AMD, not to Apple. There is no secret core on Apple chips that has control over the system. They are much better designed than AMD/Intel CPUs and strictly isolate all secondary cores behind IOMMUs. By "security processor" you probably mean the SEP (which is one of many secondary cores running Apple firmware). The SEP isn't even running when the OS boots and you can just leave it dead and choose not to use it. Other side cores are running or required to get a functional system, but none of them have unfettered access to system memory or the main CPUs (nor does the SEP even if you choose to use it). In addition, since Apple splits up coprocessor duties among many cores, that also makes it harder for one to compromise others, or for several to collude to compromise the parts of the system they do have access to. E.g. the coprocessor in charge of the display controller can't go and read your keystrokes or send a capture of the screen to the internet, because it doesn't have access to that hardware.

ChuckNorris89 5y ago
>There is no secret core on Apple chips that has control over the system. And this has been documented/proven by whom?
- marcan_42 5y ago
  This is based on having spent a year reverse engineering the platform to port Linux to it. Granted, Apple could've added a hidden secret core with secret firmware we haven't found anywhere, somehow. Of course, so could every other manufacturer. If you are concerned about all potential secret backdoors, you'll have to invest in a chip fab and make your own chips; there is no way to prove that the chip you have in your hands is not uniquely backdoored, no matter what documentation you have or not. Documentation cannot prove that the physical chip matches what was documented. What I can say is they've done a really good job keeping tight security boundaries in their chips, much better than basically every other manufacturer, by all appearances. What I meant by "secret" in my previous comment was a difficult to observe core with full system access running proprietary code, a la ME or PSP; not literally something that is deliberately hidden so as to be completely undiscoverable. So far, there is no evidence of Apple having added any questionable hardware to these chips.

ChuckNorris89 5y ago

>There is no secret core on Apple chips that has control over the system. And this has been documented/proven by whom?

marcan_42 5y ago
This is based on having spent a year reverse engineering the platform to port Linux to it. Granted, Apple could've added a hidden secret core with secret firmware we haven't found anywhere, somehow. Of course, so could every other manufacturer. If you are concerned about all potential secret backdoors, you'll have to invest in a chip fab and make your own chips; there is no way to prove that the chip you have in your hands is not uniquely backdoored, no matter what documentation you have or not. Documentation cannot prove that the physical chip matches what was documented. What I can say is they've done a really good job keeping tight security boundaries in their chips, much better than basically every other manufacturer, by all appearances. What I meant by "secret" in my previous comment was a difficult to observe core with full system access running proprietary code, a la ME or PSP; not literally something that is deliberately hidden so as to be completely undiscoverable. So far, there is no evidence of Apple having added any questionable hardware to these chips.