thr3ads.net - dovecot - Strange behaviour with BLF-CRYPT and SHA*-CRYPT pasword schemas [Mar 2019]

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Kristijan Savic - ratiokontakt GmbH

2019-Mar-06 16:16 UTC

Strange behaviour with BLF-CRYPT and SHA*-CRYPT pasword schemas

Greetings,

this is less of a bug report or a help request, but we would like to know if 
someone can explain the following:

Environment: Centos 7 with Dovecot 2.3.4-2

default_pass_scheme = BLF-CRYPT
password hash in database : BLF-CRYPT
login = works

default_pass_scheme = SHA512 or SHA256-CRYPT
password hash in database : BLF-CRYPT
login = also works

default_pass_scheme = BLF-CRYPT
password hash in database : SHA512-CRYPT
login = does not work

Can someone explain these discrepancies?

-- 
Kind regards,
Kristijan Savic

--------------------------------------------------------
ratiokontakt GmbH
Biegenhofstr. 13
96103 Hallstadt
Telefon: +49 (0) 951 9 35 35 - 0
Telefax: +49 (0) 951 9 35 35 - 902
Internet: www.ratiokontakt.de
Gesch?ftsf?hrer: Dr. Nils Kaufmann, Stefan Kraft
Amtsgericht Bamberg - HRB 3757
--------------------------------------------------------
ratiokontakt ist zertifiziert nach DIN ISO/IEC 27001
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Aki Tuomi

2019-Mar-06 16:57 UTC

head link

Strange behaviour with BLF-CRYPT and SHA*-CRYPT pasword schemas

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    On 6 March 2019 18:16 Kristijan Savic - ratiokontakt GmbH via dovecot <
    <a
href="mailto:dovecot@dovecot.org">dovecot@dovecot.org</a>>
wrote:
   </div>
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   <div>
    <br>
   </div>
   <div>
    Greetings,
   </div>
   <div>
    <br>
   </div>
   <div>
    this is less of a bug report or a help request, but we would like to know if
   </div>
   <div>
    someone can explain the following:
   </div>
   <div>
    <br>
   </div>
   <div>
    Environment: Centos 7 with Dovecot 2.3.4-2
   </div>
   <div>
    <br>
   </div>
   <div>
    default_pass_scheme = BLF-CRYPT
   </div>
   <div>
    password hash in database : BLF-CRYPT
   </div>
   <div>
    login = works
   </div>
   <div>
    <br>
   </div>
   <div>
    default_pass_scheme = SHA512 or SHA256-CRYPT
   </div>
   <div>
    password hash in database : BLF-CRYPT
   </div>
   <div>
    login = also works
   </div>
   <div>
    <br>
   </div>
   <div>
    default_pass_scheme = BLF-CRYPT
   </div>
   <div>
    password hash in database : SHA512-CRYPT
   </div>
   <div>
    login = does not work
   </div>
   <div>
    <br>
   </div>
   <div>
    Can someone explain these discrepancies?
   </div>
   <div>
    <br>
   </div>
   <div>
    --
   </div>
   <div>
    Kind regards,
   </div>
   <div>
    Kristijan Savic
   </div>
   <div>
    <br>
   </div>
   <div>
    --------------------------------------------------------
   </div>
   <div>
    ratiokontakt GmbH
   </div>
   <div>
    Biegenhofstr. 13
   </div>
   <div>
    96103 Hallstadt
   </div>
   <div>
    Telefon: +49 (0) 951 9 35 35 - 0
   </div>
   <div>
    Telefax: +49 (0) 951 9 35 35 - 902
   </div>
   <div>
    Internet: www.ratiokontakt.de
   </div>
   <div>
    Geschäftsführer: Dr. Nils Kaufmann, Stefan Kraft
   </div>
   <div>
    Amtsgericht Bamberg - HRB 3757
   </div>
   <div>
    --------------------------------------------------------
   </div>
   <div>
    ratiokontakt ist zertifiziert nach DIN ISO/IEC 27001
   </div>
  </blockquote>
  <div>
   You could configure default scheme as CRYPT. It covers these all. Otherwise
you need to make sure passwords have {SCHEME} prefix when it differs from
default or oddities occur.
  </div>
  <div class="io-ox-signature">
   <pre>---
Aki Tuomi</pre>
  </div> 
 </body>
</html>

Kristijan Savic - ratiokontakt GmbH

2019-Mar-07 12:00 UTC

head link

Strange behaviour with BLF-CRYPT and SHA*-CRYPT pasword schemas

> You could configure default scheme as CRYPT. It covers these all. Otherwise
> you need to make sure passwords have {SCHEME} prefix when it differs from
> default or oddities occur. ---
Thank you for the tip with CRYPT.

Is there any explanation for this behaviour though?

Why are BCRYPT hashes accepted when default_pass_scheme is set to SHA512-CRYPT 
and not vice versa?  Is this normal?

-- 
Regards,

Kristijan Savic

--------------------------------------------------------
ratiokontakt GmbH
Biegenhofstr. 13
96103 Hallstadt
Telefon: +49 (0) 951 9 35 35 - 0
Telefax: +49 (0) 951 9 35 35 - 902
Internet: www.ratiokontakt.de
Gesch?ftsf?hrer: Dr. Nils Kaufmann, Stefan Kraft
Amtsgericht Bamberg - HRB 3757
--------------------------------------------------------
ratiokontakt ist zertifiziert nach DIN ISO/IEC 27001
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