Manditory Access Controls (Score 1)

This is exactly the sort of thing that Manditory Access Controls is supposed to take care of. All of the work that has gone into SELinux by the NSA and others is just starting to pay off. I won't be so bold as to say Linux will have complete immunity from these types of attacks and rootkits, but it is a long way ahead of Windows.

If you want to know more about detecting kernel rootkits and cryptograhpically signed kernel modules, check out this paper by Dino Dai Zovi.