2016/01/16 1:16 "Alberto Salvia Novella" <es204904...@gmail.com>: > > [...] > > Firmware is a common concern because it can be overwritten by malware, have > malicious functionalities, or have back-doors. > > That has never been the case with microcode. It just declares the instruction > set, but is not an executable. >
Just for the record, if microcode can play with the CPU internal system state, say, the bits that specify whether the CPU is in supervisor or user state, there's not much to stop, for instance, a microcode update from providing an undocumented trap to a hidden routine in the BIOS that does deep packet inspection and arbitrary forwarding. As just one way to take advantage of microcode. -- Joel Rees Computer memory is just fancy paper, CPUs just fancy pens. All is a stream of text flowing from the past into the future.
