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ESB-2007.0645 -- [UNIX/Linux] -- BIND 8: cryptographically weak DNS query IDs

Date: 28 August 2007
References: ESB-2007.0702  ESB-2007.0709  ESB-2007.0940  

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Click here for PGP verifiable version
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===========================================================================
             AUSCERT External Security Bulletin Redistribution

                       ESB-2007.0645 -- [UNIX/Linux]
               BIND 8: cryptographically weak DNS query IDs
                              28 August 2007

===========================================================================

        AusCERT Security Bulletin Summary
        ---------------------------------

Product:              BIND 8
Publisher:            Internet Systems Consortium
Operating System:     UNIX variants (UNIX, Linux, OSX)
Impact:               Provide Misleading Information
Access:               Remote/Unauthenticated
CVE Names:            CVE-2007-2930

Original Bulletin:    http://www.isc.org/sw/bind/bind8-eol.php

Comment: Please note that BIND 8 has reached end of life and therefore will
         have no further updates.

- --------------------------BEGIN INCLUDED TEXT--------------------

		Internet Systems Consortium Security Advisory.
            	   BIND 8: cryptographically weak DNS query IDs
                  		27 August 2007

The CERT reference for this vulnerability and advisory is: CVE-2007-2930
VU#927905

Versions affected:
	BIND 8.x.x (all versions)

I. Description

ISC (Internet Systems Consortium) BIND 8 generates cryptographically
weak DNS query IDs which could allow a remote attacker to poison DNS
caches.

This bug only affects outgoing queries, generated by BIND 8 to answer
questions as a resolver, or when it is looking up data for internal
uses, such as when sending NOTIFYs to slave name servers.

- From the ISC Bind security page:

"The DNS query id generation is vulnerable to analysis which provides a
high chance of guessing the next query id. This can be used to perform
cache poisoning by an attacker."

All users are encouraged to upgrade.


II. Impact

A remote attacker could predict DNS query IDs and respond with arbitrary
answers, thus poisoning DNS caches.

III. Solution

Upgrade or Patch

This issue is addressed in ISC BIND 8.4.7-P1, available as patch that
can be applied to BIND 8.4.7.

The more definitive solution is to upgrade to BIND 9. BIND 8 is being
declared "end of life" by ISC due to multiple architectural issues.
Please see ISC's website at www.isc.org/sw/bind/bind8-eol.php for
additional information and tools.

Note that BIND 8.x.x is End of Life as of August 2007.

Users who obtain BIND 8 from their operating system vendor should see
the systems affected portion of this document for a partial list of
affected vendors.

Acknowledgments

Thanks to Amit Klein from Trusteer (www.trusteer.com) for
reporting this.
__________________



- --------------------------END INCLUDED TEXT--------------------

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===========================================================================
Australian Computer Emergency Response Team
The University of Queensland
Brisbane
Qld 4072

Internet Email: auscert@auscert.org.au
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===========================================================================

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