Before all, sorry if my english isn't extraordinary because, i'm a french user of your apps.
I've read few days ago that a new type of malware was discovered by the Kaspersky Lab .
It's hidden in the firmware of IBM, Samsung, Maxtor, Western Digital Toshiba and Seagate HDD.
With other malware like Regin or Stuxnet for example, it's seems possible to stole important informations on PC without detection by classic antimalware apps.
french source : http://www.numerama.com/magazine/32247-grayfish-un-trojan-dissimule-dans-les-disques-durs-revele-par-kaspersky.html
english article, more technical : http://arstechnica.com/security/2015/02/how-omnipotent-hackers-tied-to-the-nsa-hid-for-14-years-and-were-found-at-last/
Kaspersky Lab repport : https://securelist.com/files/2015/02/Equation_group_questions_and_answers.pdf