Linux-kernel mailing list archive 1999-23,: Re: R: Do not use stock RedHat 6.0 kernels with SMBFS! [OFF-TOPIC]

# Re: R: Do not use stock RedHat 6.0 kernels with SMBFS! [OFF-TOPIC]

A. Wik (aw@mail1.bet1.puv.fi)
Fri, 11 Jun 1999 22:16:15 +0300 (EEST)

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On Fri, 11 Jun 1999, Michael H. Warfield wrote:

> A. Wik enscribed thusly:
> > On Thu, 10 Jun 1999, Steve Dodd wrote:
> > > On Thu, Jun 10, 1999 at 06:48:30PM +0000, A. Wik wrote:
> > > > Besides, unless public-key
> > > > cryptography is used, passwords have to be stored in plain-text (or
> > > > another sensitive format) on disk if they are to be encrypted on the
> > > > network.
>
> > > Rubbish. Store a secure one-way hash of the password. The problem is just
> > > in choosing a secure algorithm.
>
> > No, the one-way hashes are still sensitive (more so than a shadow file).
>
> And what exactly do you think is stored in the shadow file?
>
> Clue alert: They are one-way hashes! It uses either a DES based
> hash with the password as the key to encrypt a known value or using MD5!

There's a BIG difference: the standard Unix password hashes are never
used as encryption keys. The only thing they are useful for (to an
authentication program or password cracker) is for comparision (when
verifying a plaintext password). This is not the case with SMB hashes.

> There are "other techniques" which are not in general circulation
> for busting certain password attributes off the wire with SMB protocols
> but nothing that's inherent with one-way hashes in general.

The inherent problem with traditional, secret-key cryptography is the
fact that there must be a shared secret. When using encrypted SMB
passwords the secret is the hash which is stored on disk. When using
plaintext SMB (or telnet, ftp...) the shared secret is the actual
password.

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