... "And in some cases, it planted spyware on computers' firmware, the programming that lives permanently on hardware. It's an unheard-of move that means the malware can avoid detection by antivirus software. Reinstalling a computer's operating system or reformatting the hard disk won't even fix the problem." ...
http://money.cnn.com/2015/02/17/technology/security/malware-nsa/index.html?iid=HP_LN