I am late to this game so I assume everyone else’s brain was melted by this in 2017: Every Intel CPU since 2008 includes an autonomous computer called the Intel Management Engine that runs Minix, completely circumvents your own OS, has full access to memory, has network access, and cannot be turned off by the owner of the hardware (you). We also don’t know what it does because it’s extremely difficult to reverse engi…
Yes and no. It could potentially use the network. To do so, it would have to acquire an IP address, which in the case of IPv4 would show as ARP messages. More significantly, any attempt to call out could be detected at the router (IPv4 or IPv6). Now I know that most people don't look through firewall logs looking for comms from unexpected internal addresses - but some people do. And since this has been around since 2…
We don't _really_ know this. It could of course wait for a signal (say, in a certain memory region, depending on the host OS) and be activated only by remote control in collaboration with other vectors, for special use against, say, heads of state, or the rare meaningful dissidents against whoever it is who has access.