Security Basics mailing list archives

RE: ADS Password Storage Protection


From: "Roger A. Grimes" <roger () banneretcs com>
Date: Wed, 19 Jul 2006 23:01:51 -0400

In Windows it is LM or NT (sometimes called NTLM) hashes.

NTLMv2 refers to the authenication protocol that exchanges the hash
between the client and server authentication database. Windows has four
choices: Kerberos, NTLMv2, NTLM, and LM. The last two are week, the
first two are strong. You can sniff password hashes (i.e. LM or NT) out
of the authentication streams...but rainbow tables only store password
hashes. 

-----Original Message-----
From: Depp, Dennis M. [mailto:deppdm () ornl gov] 
Sent: Tuesday, July 18, 2006 12:50 PM
To: Eoin Miller; eric.baechle () dhs gov
Cc: security-basics () securityfocus com
Subject: RE: ADS Password Storage Protection

I may be wrong, but I thought rainbow tables only worked with NTLM
passwords.  If you force the passwords to be NTLMv2, rainbow tables are
not useful in cracking the passwords. 

Dennis

-----Original Message-----
From: Eoin Miller [mailto:eoin.miller () trojanedbinaries com]
Sent: Monday, July 17, 2006 6:20 PM
To: eric.baechle () dhs gov
Cc: security-basics () securityfocus com
Subject: Re: ADS Password Storage Protection

eric.baechle () dhs gov wrote:
Winshel;

Actually, a passphrase is not as secure as a random password.  As you
probably have heard, "Don't use dictionary words" over and over again.
Even compound dictionary words are bad, ie: "firedogdalmation".
Compounding dictionary words with spaces, punctuation, and even
gramatically correct modifiers in between is really no different than
without.  It's a very simple substitution to try; "firedogdalmation" and
then try "fire dog dalmation", "Fire Dog Dalmation", "Dalmation the Fire
Dog", etc.

Using compound dictionary words could come back to bite you very
quickly, even when used in long phrases.

Sincerely,

Eric Baechle, CISSP/ISSEP, etc.
Senior INFOSEC/OPSEC Engineer
Department of Homeland Security

  
Password length is still extremely important. A completely randomized 8
character length password is still no match for an attacker with the
rainbow tables at their disposal. Complexity requirements should still
be employed, but having a length requirement of less than 12 characters
is not adaquate. I believe the idea expressed by Winshel of length being
more important than randomness is a result of these types of precomputed
hash attacks.

--Eoin

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