Hidden inside Intel CPU chips is a separate CPU with its own MINIX operating system and a software stack, which includes networking and a web server. Designed so the user can't access it, can never see what code is running on it or even know that it's there and it can be easily used to take over your computer EVEN WHEN IT'S TURNED OFF.
Some are wondering if the government might use this for surveillance. I'm wondering when it will leak that this was put in at government request:
http://www.zdnet.com/article/minix-intels-hidden-in-chip-operating-system/
https://tech.slashdot.org/story/17/11/07/1041236/minix-intels-hidden-in-chip-operating-system