Security Basics: Re: Password Audits

[Adam Jones <ajones1 () gmail com>]

LC5 breaks windows passwords by looking at the NT Lan Manager version
of them. NTLM is an old way of storing passwords that truncates them
to 14 characters (IIRC it also pads them to 14 if needed) then it
splits it into two seven character strings and encrypts each one
separately.

This makes the passwords easier to break, as you only have to hit one
half of it and can use that for dictionary attacks against the other
half. The first 14 characters should be enough to help you gauge the
strength of the password. It is possible to find software that will
work with other encryption schemes, but none can achieve the cracking
speed you get on NTLM.

In short, yes, tools do exist to do it, but you should seriously
consider if the extra time expended is worth it. In many cases it will
be more time effecient to just evaluate the first 14 characters.

Also check your security profiles to ensure that NTLM authentication
is disabled, otherwise anything after the first 14 characters is
practically useless to begin with.

On 4/22/05, Jair <jairgerald () hotmail com> wrote:
> Hi Fellows,
>
> I am using LC5 tool for audit windows 2000 users passwords and look like it
> only work with 14 characters passwords or less, I know some users have some
> long passwords over 14 characters and LC5 doesn't show me information about
> them.
>
> do you guys know if is a tool who can break long passwords ?
>
> Thanks for you help