Re: Windows XP / 2K3 Default Users

["Lee Lawson" <leejlawson () gmail com>]

Not quite sure where you are going here, but...

Since NT4 SP3 (I think) the password hashes in the SAM file have been
encrypted with DES at 128 bit.  The hashes are decrypted on boot up so
that the system can authenticate users.

If you can obtain the SAM file, in the same directory is the 'system'
file.  This holds the boot key, or to be really specific, the DES
symmetric encryption/decryption key.  This key needs to be extracted
correctly (Cain & Abel or bkhive).

In the now decrypted SAM file will be the LM hashes and NTLM hashes.
There are two instances where the LM hashes will all be blank:
1) The password is longer than 14 characters.
2) The registry change has been made to prevent storing passwords with
LM and I agree that I cannot see why people would not switch it off,
but then don't.  Oh well.

If you are to use Rainbow Tables, the disk space required for LM is
over 200 Gb although I have 47 GB and that has not failed to crack a
password.  If you want to start cracking NTLM hashed passwords, you
are going to need much more disk space, over 500 Gb!  This means that
it is just as easy to do, as long as you have the disk space!

So, NTLM hashes are just as easy to break, they will take longer as
the tables to look through are bigger.

The Rainbow Tables for each algorithm need to be created yourself or
purchased/stolen/downloaded/shared.  You can buy them from:
http://www.rainbowtables.net/
http://www.rainbowcrack-online.com/

There are, at present that I know of, tables for: LM, NTLM, MD4, MD5,
CiscoPIX, MySQL and SHA1, but any can be made if you have the source
code for the algorithm.

Don't know if this has cleared anything up, but there you go...




On 10/30/06, Thor (Hammer of God) <thor () hammerofgod com> wrote:
> You "routinely" crack passwords on SAM's that are SYSKEY'd by default
> (128-bit) with rainbow tables?  XP/2k3 has syskey on by default... And any
> password over 14 characters automatically clear the LM hash, even if you
> have not turned it off (which I can't imagine anyone not doing.)
>
> So, I'm guessing that the "rainbow table" hubbub is all 40-bit, or silly LM
> hash cracking, right?  Or am I missing something here?
>
> t
>
>
>
> On 10/26/06 2:07 PM, "ep" <captgoodnight () hotmail com> spoketh to all:
>
> > I crack these routinely when pentesting/playing, granted, it's by pushing
> > the sam through rainbow tables, thus admin access...
> > Basically, any sam once in hand, is cracked these days via rainbowtables.
> > There're ways to prevent this from happening, but most admins don't go that
> > extra step...
> >
> > --cg
> >
> > -----Original Message-----
> > From: listbounce () securityfocus com [mailto:listbounce () securityfocus com] On
> > Behalf Of Joey Peloquin
> > Sent: Wednesday, October 25, 2006 12:38 PM
> > To: s-williams () nyc rr com; Pen-Testing
> > Subject: Re: Windows XP / 2K3 Default Users
> >
> > s-williams () nyc rr com wrote:
> >> Hello list this might be an easy question to answer but have anyone
> >> been sucessful in using windows built in default accounts when doing a
> >> password audit. I
> > know  most
> >> xp machines has (help assitant and support_xxxxxxxx). Is their a
> >> default
> > list out
> >> there some where with various vendor OS  passwords, or a way to figure
> >> out the password for these accounts.
> >> Sent via BlackBerry from T-Mobile
> >
> > You can try to crack them through normal means, but it'd likely be a futile
> > act since a) they are randomized and *extremely* complex (as far as I
> > recall) and b) even my ~13 year old knows to restrict these accounts.  There
> > are clueless admins out there though, so, *shrug*.
> >
> > -jp
> >
> >
> >
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--
Lee J Lawson
leejlawson () gmail com
leejlawson () hushmail com

"Give a man a fire, and he'll be warm for a day; set a man on fire,
and he'll be warm for the rest of his life."

"Quidquid latine dictum sit, altum sonatur."

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