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


From: "Jim C. Nasby" <decibel () decibel org>
Date: Wed, 20 Apr 2005 16:23:23 -0500

On Wed, Apr 20, 2005 at 05:03:18PM -0400, Tom Lane wrote:
  This would allow for the pregeneration of the entire md5
  keyspace using that 'salt' and then quick breakage of the hash once
  it's retrieved by the attacker.

Considering the size of the possible keyspace, this is pretty silly.

Actually, it's not as silly as you think. You can download rainbow
tables for Windows/LanMan passwords up to 14 or 15 characters in length.
Given the password hash and some code, you can determine the user's
password in a matter of minutes.

Simply put, MD5 is no longer strong enough for protecting secrets. It's
just too easy to brute-force. SHA1 is ok for now, but it's days are
numbered as well. I think it would be good to alter SHA1 (or something
stronger) as an alternative to MD5, and I see no reason not to use a
random salt instead of username.
-- 
Jim C. Nasby, Database Consultant               decibel () decibel org 
Give your computer some brain candy! www.distributed.net Team #1828

Windows: "Where do you want to go today?"
Linux: "Where do you want to go tomorrow?"
FreeBSD: "Are you guys coming, or what?"


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