With the new generation of Intel architecture-based Ivy Bridge was presented a new hardware-based security. It's called Intel SMEP.
It adds a headache when exploiting vulnerabilities kernel mode, Like bit NX, prevents code execution on the memory page.
In turn, Microsoft has implemented support for SMEP in Windows 8, thereby making the OS more secure. However, the first implementation of the "head-on" support SMEP turned with a small defect, through which the attacker is still possible for a relatively painless operation vulnerabilities.