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Bitlocker and cracked logons


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Guest DWalker07
Posted

Bitlocker and Bitlocker for Windows 7 are supposed to be great at

preventing stolen disks or stolen computers from having their disks

compromised by being installed in another computer (or by booting the

computer with another OS).

 

But, if you steal a computer, there are lots of tools on the 'net that will

crack logon passwords. How does Bitlocker help in these situations? If

someone can crack the logon password, then they are the person that the

BitLocker disks are decrypted for.

 

Any information would be appreciated. (I am currently using a third-party

decryption tool that requires me to enter the passkey every time I mount

the disk.)

 

David Walker

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Guest Robert Kochem
Posted

DWalker07 schrieb:

<span style="color:blue">

> But, if you steal a computer, there are lots of tools on the 'net that will

> crack logon passwords. How does Bitlocker help in these situations? </span>

 

To crack the passwords you have to boot form an alternate medium (USB, CD,

DVD..). This modifies the boot process and therefore the TPM blocks and

your disks are not accessible. No access to disk means no possibility to

read or modify the password storage...

 

Robert

Guest DWalker07
Posted

Robert Kochem <robert@mailueberfall.de> wrote in

news:18uwzfx0otccl$.1cofalehcyeun.dlg@40tude.net:

<span style="color:blue">

> DWalker07 schrieb:

> <span style="color:green">

>> But, if you steal a computer, there are lots of tools on the 'net

>> that will crack logon passwords. How does Bitlocker help in these

>> situations? </span>

>

> To crack the passwords you have to boot form an alternate medium (USB,

> CD, DVD..). This modifies the boot process and therefore the TPM

> blocks and your disks are not accessible. No access to disk means no

> possibility to read or modify the password storage...

>

> Robert

> </span>

 

BUT, once you have cracked the password, you can then boot the stolen

computer normally and use the cracked logon password. Right? Then,

BitLocker will nicely unlock the disks for you.

 

Am I missing something?

 

David Walker

Guest DWalker07
Posted

Robert Kochem <robert@mailueberfall.de> wrote in

news:18uwzfx0otccl$.1cofalehcyeun.dlg@40tude.net:

<span style="color:blue">

> DWalker07 schrieb:

> <span style="color:green">

>> But, if you steal a computer, there are lots of tools on the 'net

>> that will crack logon passwords. How does Bitlocker help in these

>> situations? </span>

>

> To crack the passwords you have to boot form an alternate medium (USB,

> CD, DVD..). This modifies the boot process and therefore the TPM

> blocks and your disks are not accessible. No access to disk means no

> possibility to read or modify the password storage...

>

> Robert

> </span>

 

OH, I think I misunderstood your post, sorry.

 

So, if you let Windows 7 install the 100 MB special partition, and let the

system boot from there, then the cracking programs can't get access to the

main system partition. Hmmm....

 

I see that Vista can also create this small boot partition.

 

How long until the crackers get around this? I wonder if it's possible...

 

Thanks.

 

David Walker

Guest John Barnett MVP
Posted

My machine doesn't have a TPM therefore I have to use a USB stick to use

Bitlocker. The password actually doesn't have anything to do with it. When I

boot my machine the first thing is asks for is the USB stick, without it I

can't do anything let alone get anywhere to change or hack a password. So if

someone stole my PC they would also need the USB stick with the Bitlocker

encrypted code on to access my PC and as that is locked away they might get

one item but not the two.

 

--

 

--

John Barnett MVP

Windows XP Associate Expert

Windows Desktop Experience

 

Web: http://www.winuser.co.uk

Web: http://xphelpandsupport.mvps.org

Web: http://vistasupport.mvps.org

Web: http://www.silversurfer-guide.com

 

The information in this mail/post is supplied "as is". No warranty of any

kind, either expressed or implied, is made in relation to the accuracy,

reliability or content of this mail/post. The Author shall not be liable for

any direct, indirect, incidental or consequential damages arising out of the

use of, or inability to use, information or opinions expressed in this

mail/post..

 

 

"DWalker07" <none@none.com> wrote in message

news:eu8u8vpyJHA.4632@TK2MSFTNGP02.phx.gbl...<span style="color:blue">

> Robert Kochem <robert@mailueberfall.de> wrote in

> news:18uwzfx0otccl$.1cofalehcyeun.dlg@40tude.net:

><span style="color:green">

>> DWalker07 schrieb:

>><span style="color:darkred">

>>> But, if you steal a computer, there are lots of tools on the 'net

>>> that will crack logon passwords. How does Bitlocker help in these

>>> situations?</span>

>>

>> To crack the passwords you have to boot form an alternate medium (USB,

>> CD, DVD..). This modifies the boot process and therefore the TPM

>> blocks and your disks are not accessible. No access to disk means no

>> possibility to read or modify the password storage...

>>

>> Robert

>></span>

>

> OH, I think I misunderstood your post, sorry.

>

> So, if you let Windows 7 install the 100 MB special partition, and let the

> system boot from there, then the cracking programs can't get access to the

> main system partition. Hmmm....

>

> I see that Vista can also create this small boot partition.

>

> How long until the crackers get around this? I wonder if it's possible...

>

> Thanks.

>

> David Walker </span>

Guest FromTheRafters
Posted

"DWalker07" <none@none.com> wrote in message

news:eu8u8vpyJHA.4632@TK2MSFTNGP02.phx.gbl...<span style="color:blue">

> Robert Kochem <robert@mailueberfall.de> wrote in

> news:18uwzfx0otccl$.1cofalehcyeun.dlg@40tude.net:

><span style="color:green">

>> DWalker07 schrieb:

>><span style="color:darkred">

>>> But, if you steal a computer, there are lots of tools on the 'net

>>> that will crack logon passwords. How does Bitlocker help in these

>>> situations?</span>

>>

>> To crack the passwords you have to boot form an alternate medium

>> (USB,

>> CD, DVD..). This modifies the boot process and therefore the TPM

>> blocks and your disks are not accessible. No access to disk means no

>> possibility to read or modify the password storage...

>>

>> Robert

>></span>

>

> OH, I think I misunderstood your post, sorry.

>

> So, if you let Windows 7 install the 100 MB special partition, and let

> the

> system boot from there, then the cracking programs can't get access to

> the

> main system partition. Hmmm....</span>

 

You may want to read up on TPM (Trusted Platform Module) to see what

Bitlocker's or the OS's support of this mechanism means to the boot

process. I think your question is more along the lines of how TPM works

than specifically about Bitlocker.

<span style="color:blue">

> I see that Vista can also create this small boot partition.

>

> How long until the crackers get around this? I wonder if it's

> possible...</span>

 

Physical access to a machine, and time, is all that is needed. How much

time is often the limiting factor. They can own the TPM (with physical

presence - or remotely) in much less time than it would take to decrypt

any encrypted information.

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