Bugtraq mailing list archives

Re: [HACKERS] Postgres: pg_hba.conf, md5, pg_shadow, encrypted passwords


From: "Jim C. Nasby" <decibel () decibel org>
Date: Wed, 20 Apr 2005 17:08:30 -0500

On Wed, Apr 20, 2005 at 06:03:18PM -0400, Tom Lane wrote:
Well, I have no particular problem with offering SHA1 as an alternative
hash method for those who find MD5 too weak ... but I still question the
value of putting any random salt in the table.  AFAICS you would have to
send that salt as part of the initial password challenge, which means
any potential attacker could find it out even before trying to
compromise pg_shadow; so Stephen's argument that there is a useful
improvement in protection against precomputation of password hashes
still falls down.

BTW, one could also ask exactly what threat model Stephen is concerned
about.  ISTM anyone who can obtain the contents of pg_shadow has
*already* broken your database security.

FWIW, I do think there's some benefit to not being able to pre-compute
an entire hash table for accounts such as 'postgres' and 'www'. But I
agree it would be useful to know the actual threat model.
-- 
Jim C. Nasby, Database Consultant               decibel () decibel org 
Give your computer some brain candy! www.distributed.net Team #1828

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