Simon Says – Musings of a Technology CTO

Last month Joanna Rutkowska posted a very interesting article showing a practical “Evil Maid” attack against the open-source TrueCrypt FDE product.  The attack is reasonably simple, subvert the pre-boot authentication engine of the full-disk encryption product in question to add a password-sniffing routine, then wait for the unsuspecting user to authenticate to their machine and then retrieve the credentials at a later stage.

Evil Maid is simply hooking the pre-boot code of TrueCrypt and adding a routine to store the users password. Because the TrueCrypt code is quite simple, it’s a relatively easy thing to do, but the attack is theoretically valid regardless of this fact, just the effort to make the hook code increases with the sophistication of the pre-boot environment. Read more…