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Home » Hacking News » Authentication bypass vulnerability in Blahz-DNS

Authentication bypass vulnerability in Blahz-DNS

by Nikola Strahija on April 29th, 2002 Blahz-DNS is PHP/MySQL based DNS (BIND 9) administration with support for primary and secondary zones, user authentication, User and Admin account types, and restricted access for user accounts to certain primary and secondary zones. Unfortunately the security concept is broken by design. One can easily access any page different to login.php without any proper password.

More details
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The software is using a very poor security concept: The user is only
asked for a valid user password combination at the login page. Access
to any other page is granted without any password.

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At a blackhat
can change existing users (eg. changing passwords) or add new users
without beeing authorized.

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Use apache's .htpasswd to temporary restrict access to blahzdns.

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Use at least version 0.25.

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A blackhat can easily manipulate DNS entries remotly without being
authorized in any way. This often is the first step of a hacking
scenario. Therefore we are rating the security risk to very high.

Vendor status
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The author has reacted very fast and published a new version in less
than 12 hours. All users are encouraged to upgrade.

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All information that can be found in this advisory is believed to be
true, but maybe it is not. ppp-design can not be held responsible for
the use or missuse of this information. Redistribution of this text is
only permitted if the text has not been altered and the original
author ppp-design ( is mentioned.

This advisory can be found online:

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Fingerprint: 5B02 0AD7 A176 3A4F CE22 745D 0D78 7B60 B3B5 451A
Version: GnuPG v1.0.6 (GNU/Linux)
Comment: Weitere Infos: siehe


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