AsIO2_64.sys and AsIO2_32.sys in ASUS GPUTweak II before 2.3.0.3 allow low-privileged users to interact directly with physical memory (by calling one of several driver routines that map physical memory into the virtual address space of the calling process) and to interact with MSR registers. This could enable low-privileged users to achieve NT AUTHORITY\SYSTEM privileges via a DeviceIoControl.