forgot to add this to the initial reply.
If your using the defualt windows AD policy settings to enforce
upper/lower/alpha-numeric passwords AND your using NT/NTLM hashes your
wasting your time. The Windows NT/NTLM method automatically converts
all text charachters to upper case when it creates the hash for
storage. A cracker only has to compute upper case and alpha at that
point and your pass strength is weakend by degrees.
thanks,
bf
On 1/20/06, bf <illuminatus.master@gmail.com> wrote:
I'm going to keep this short as it could easily become several pages
long... use google for more information on a specific subject.
In addition to the previous posts by others consider the following.
The vulnerability lies in the use of the default NT/NTLM hashes for
authentication in windows active directory. In addition to what are
normally considered "best practices" for windows passwords you need to
use windows active directory group policy to force NTLMv2
challange/response only.
NT/NTLM password hashes up to 14 charachters are easily cracked
(typically less than 2 hours with a 85% success rate with the files I
typically use) by using something like rainbow tables or Ophcrack. If
you don't believe me go ahead and download pwdump3 and Ophcrack with
the "big" table. Dump the hashes from your Win32 DC into a txt file
and feed it into Ophcrack, go to lunch, come back and view your
passwords.
In short, deny NT/NTLM and force NTLMv2 or use passwords over 14
charachters in addition to best practices and you should be "ok".
Google for terms like "disable ntlm hash" and you'll find more
information. btw: you need to prevent your Win32 DC's from storing the
NT/NTLM hashes locally (duh), microsoft technet provides info on which
registry keys to edit to make this happen.
enjoy your weekend.
bf
On 1/19/06, Sulaiman, Wilmar <wsulaiman@siddharta.co.id> wrote:
Dear all,
I noticed that "best practice" for Minimum password length policy is
either 6 or 8 characters. I guess SANS institute considered a weak
password if it is less than 8 characters.
I would like to know where they derived the number (6 and 8 characters).
Is there any documentation to backup it up why the best practice for
minimum password length is set to 6?
Wilmar Sulaiman
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