RE: Bitlocker without PIN

Speaking as an individual and not representing my institution. If you can h=
andle the support overhead I would require the PIN or physical key in addit=
ion to the transparent TPM key for added protection.=20

Re: What happens if he boots with a linux live CD/USB? Can he decrypt the d=
rive? The key is stored in the TPM. Does linux have access to the TPM?

No. This is not a viable attack, these links explain in a nutshell how TPM =
works:
http://windows.microsoft.com/en-US/windows-vista/BitLocker-Drive-Encryption=
-Overview
http://geekswithblogs.net/sdorman/archive/2006/07/04/84045.aspx

There are a number of viable attacks (and plenty more theoretical attacks) =
against all types of full drive encryption, including BitLocker, but it is =
not as trivial as using a Linux bootdisk.

Re: We are just not sure if the extra security worths having the users to t=
ype 2 passwords to boot a laptop.

If the attacker can gain physical access to the computer, and it uses TPM a=
nd boots straight to Windows, then they could attack the computer at the ne=
twork layer and at the console, or via one of the more advanced hardware at=
tacks (chip cooling, hibernation file excavation, etc.). Requiring a PIN at=
 boot adds an extra layer of protection before the OS starts.

It comes down to a risk analysis of your environment and what you are tryin=
g to protect. For my laptop I use TrueCrypt (which by design requires a PIN=
) because it is a transient computer at risk for theft and contains informa=
tion that could be leveraged in an attack against our infrastructure. Furth=
ermore I use KeePass to encrypt all passwords, and AxCrypt for all sensitiv=
e documents, which offers a second layer of protection should the computer =
be compromised while it is booted.

It should be pointed out that BitLocker/TrueCrypt/EFS/etc. will do little o=
r nothing to stop an attack inbound from the network or malicious code that=
 has been allowed to execute on the running OS.=20

Best,
alex


Alex Keller
Systems Administrator
Academic Technology, San Francisco State University
Office: Burk Hall 153 Phone: (415)338-6117 Email: [email protected]

-----Original Message-----
From: [email protected] [mailto:[email protected]] On=
 Behalf Of Shang Tsung
Sent: Thursday, February 17, 2011 3:07 AM
To: [email protected]
Subject: Bitlocker without PIN

Hello all,

We are on the process of setting up Bitlocker on our laptops for OS encrypt=
ion and we are wandering if we should set up a PIN or not. If we do not, th=
e attacker can get to Windows login screen, but this is where he will stop.

What happens if he boots with a linux live CD/USB? Can he decrypt the drive=
? The key is stored in the TPM. Does linux have access to the TPM?

We are just not sure if the extra security worths having the users to type =
2 passwords to boot a laptop.

ST