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Re: Re[2]: Encryption on Laptops?
From: Bart.Lansing () kohls com
Date: Fri, 26 Mar 2004 12:36:46 -0600






Alexander,

I do indeed stand (well, sit..I was never much for keyboarding while
standing) corrected...we do need to take the time to brute the
user'spassword once we own the box.  Still, trivial for anyone who really
wants the files :)

Bart Lansing
Manager, Desktop Services
Kohl's IT


Alexander Lukyanenko <sashman () ua fm> wrote on 03/25/2004 03:49:59 PM:

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Hash: SHA1

Hello Bart et al,
...
BLkc>    I simply change the
BLkc>  user account passwords on the box in question, log in as
BLkc> the user, and voila, I have the
BLkc>  files.
Nonsense! The idea of EFS is that the encryption keys
(`certificates') are itself
encrypted with user's passwords. If you don't know the password,
you won't get to the files, and if you'll forcibly change the user's
password, you'll kill the certificate and render the encrypted files
unreadable.
But, the system can still be "opened".
You can boot with ERD/ntpasswd, change admin's password, boot
Windows as usual, login, run pwdump/lc4, get the password hashes and then
brute-force them using lc4 or John The Ripper (don't sure about the
later being able to deal with NTLM2 hashes). Then you login as the
user in question with his/her password and voila, you have the files.
It ain't as easy and fast (you need to bruteforce a password), as just
changing a user's password, but still possible.

Cheers,
* * * * * * * * * * * * * * *
* Alexander V. Lukyanenko   *
* ma1lt0: sashman ua fm     *
* ICQ#  : 86195208          *
* Phone : +380 44 458 07 23 *
* OpenPGP key ID: 75EC057C  *
* NIC   : SASH4-UANIC       *
* * * * * * * * * * * * * * *
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