FDE and integrity of OS Was: How to Test HDD Encryption

[Alexander Klimov <alserkli () inbox ru>]

On Tue, 13 Nov 2007, Ansgar -59cobalt- Wiechers wrote:
> > But isn't FDE primarily targeted at protecting data from lost or
> > stolen systems? A bit over 40% of data breaches are due to lost or
> > stolen devices.
>
> That's its primary use. However, FDE also protects the integrity of
> the operating system while the computer is not running.

FDE can make tampering with your OS slightly harder but it does not
protect OS integrity in any strong sense. Consider the following
example (inspired by `Vbootkit' and `Blue Pill'): attacker who has
temporary physical access to your computer (while it is switched off)
changes the system so that attacker's software loads first (the
attacker changes boot-sector or reflash BIOS), this software loads the
rest of the system in a virtual environment. For the user the system
looks exactly the same as it was (e.g., the system asks for password
or a smart card and decrypts the OS), but in reality the attacker has
complete control.

-- 
Regards,
ASK