I misread this paragraph: As a matter of fact, several vulnerabilities in Intel ME have been discovered in the past. Among others, Ermolov, Sklyarov, and Goryac

I misread this paragraph: As a matter of fact, several vulnerabilities in Intel ME have been discovered in the past. Among others, Ermolov, Sklyarov, and Goryachy described a method to extract the secret key that is used inside the CPU to decrypt microcode updates, which also led to the possibility of executing your own microcode on the CPU or reading Intel's microcode. Where it talked about extracting the secret key.