on Tue, Dec 16, 2003 at 05:34:02PM -0600, Jacob S. ([EMAIL PROTECTED]) wrote:
> On Tue, 16 Dec 2003 20:22:03 -0300
> Diego Crivelli <[EMAIL PROTECTED]> wrote:
> 
> <snip>
> > I created a user on my woody box with adduser and when prompted for
> > the password I wrote a word with more than 8 characters. But I can
> > login by supply only the first 8 characters. I tried changing the
> > 'maxlength' value on login.defs, didn't work. So, how can I use
> > passwords of more than 8 characters?. Thanks. 
> <snip>
> 
> Howdy Diego,
> 
> As root, run "dpkg-reconfigure passwd". It will bring up a dialog box
> asking if you want to enable md5 passwords - answer Yes, and then it
> will allow you to use passwords longer than 8 characters.

    $ man 3 crypt

Explanation being:  the default "crypt" Unix passwords (used for
compatibility and tradition) only encode the first 8 bytes of a
password (low 7 bits of each character, 56 bits), along with a two byte
"salt" (4096 possible values).

In the past week or so, a project has demonstrated that it's possible to
effectively precompute all crypted, salted values on reasonably attainable
hardware, making brute forcing passwords possible:

    http://slashdot.org/article.pl?sid=03/12/08/192205
    http://security.sdsc.edu/publications/teracrack.pdf


Peace.

-- 
Karsten M. Self <[EMAIL PROTECTED]>        http://kmself.home.netcom.com/
 What Part of "Gestalt" don't you understand?
    We are the unwilling... led by the unqualified... to do the
    unnecessary...  for the ungrateful...
    -- GI in Vietnam, 1970

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