full-disclosure - Re: #warning -- DICE.COM insecure passwords

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Date: Tue, 12 Feb 2013 14:14:48 -0800
From: Tim <tim-security@...tinelchicken.org>
To: Valdis.Kletnieks@...edu
Cc: "full-disclosure@...ts.grok.org.uk" <full-disclosure@...ts.grok.org.uk>
Subject: Re: #warning -- DICE.COM insecure passwords

> That's assuming that they didn't do the risk analysis and decide that
> the effort required to fix the problem (which will probably require,
> among other things, having every single user change their password)
> is worth the effort.  Given that so many places have gotten hacked and
> pwned that the user community response is usually "Meh. Another one",
> they may rightfully have concluded that risking public shaming is
> in fact a good business decision...

Here's a bit of pseudocode for you Valdis:

for each user:
  let user.new_hash = scrypt(user.old_crypt_hash)

# now update authentication routine to use user.new_hash with new
# nested hashing algorithm

So really, there's actually not a good reason to keep a crappy hash
database around.  Just add a layer of good salted hashing on top.

With that said, the unusual quirk of crypt being limited to 7
characters is an additional challenge, but you can start with the
above steps (which immediately improves security), and then slowly
transition to using scrypt alone or some variant that supports longer
passwords.

tim

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