Intel Management Engine
Vulnerable and proprietary low-level hardware parts … advanced attacks.
The Intel Management Engine (ME) is a type of separate computer within all modern Intel processors (CPU). The ME acts as a master controller for your CPU and has extensive access to your computer (system memory, display, keyboard, network). Intel controls the code of the ME and severe vulnerabilities have already been found in the ME that allow local and remote attacks. Therefore, ME can be considered a backdoor.
Virtual Intel Software Guard Extensions (vSGX)