"Design flaw in Intel processors opens door to rootkits, researcher says"
[http://www.pcworld.com/article/2965872/components-processors/design-flaw-in-intel-processors-opens-door-to-rootkits-researcher-says.html]
This is similar to the Apple vulnerability that was in the news recently. In order to work it needs low level access in Windows, so in theory the systems most at risk, then as now are laptops that had to be handed over for inspection crossing borders etc., though if a system has already been badly compromised or infected, it's expected that it could download & use this new exploit as well.
The exploit itself targets the firmware, which is software stored in the chips themselves rather than on any disk, & it's 1st used when the system's powered on. Mal-ware code starting so early in the chain of events is difficult to detect, & get rid of, & since it started before anything else, can modify or effect anything else further down that chain.
Intel was aware of the problem, & CPUs starting with Sandy Bridge do not have this vulnerability.