Qube OS is made by quite good security researchers, who where first to break into Intel SMM, as far as I know. Qube OS separates domain as virtual machines on

Qube OS is made by quite good security researchers, who where first to break into Intel SMM, as far as I know. Qube OS separates domain as virtual machines on top of Xen and you need to do privilege escalation in the sandbox first, then to break Xen somehow. Sure, Xen is still a lot of code to attack, but it's much smaller than Linux kernel or XWindow.