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             AUSCERT External Security Bulletin Redistribution

                              ESB-2012.0701.2
           Heavy DNSSEC Validation Load Can Cause a "Bad Cache"
                        Assertion Failure in BIND9
                               26 July 2012

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

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

Product:           BIND
Publisher:         Internet Systems Consortium
Operating System:  UNIX variants (UNIX, Linux, OSX)
                   Windows
Impact/Access:     Denial of Service              -- Remote/Unauthenticated
                   Provide Misleading Information -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2012-3868 CVE-2012-3817 

Original Bulletin: 
   https://kb.isc.org/article/AA-00729

Comment: Note: This bug cannot be encountered unless your server is doing 
         DNSSEC validation.

Revision History:  July 26 2012: Added DoS to Impact/Access
                   July 25 2012: Initial Release

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Heavy DNSSEC Validation Load Can Cause a "Bad Cache" Assertion Failure in BIND9

Summary:
High numbers of queries with DNSSEC validation enabled can cause an assertion 
failure in named, caused by using a "bad cache" data structure before it has 
been initialized.

CVE:               CVE-2012-3817

Document Version:  2.0
Posting date:      24 July, 2012
Program Impacted:  BIND 9
Versions affected: 9.6-ESV-R1 through 9.6-ESV-R7-P1; 9.7.1 through 9.7.6-P1; 
9.8.0 through 9.8.3-P1; 9.9.0 through 9.9.1-P1.

Severity: Critical

Exploitable: Remotely

Description:
BIND 9 stores a cache of query names that are known to be failing due to
misconfigured name servers or a broken chain of trust. Under high query loads
when DNSSEC validation is active, it is possible for a condition to arise in
which data from this cache of failing queries could be used before it was fully
initialized, triggering an assertion failure.

This bug cannot be encountered unless your server is doing DNSSEC validation.

Please Note: Versions of BIND 9.4 and 9.5 are also affected, but these 
branches are beyond their "end of life" (EOL) and no longer receive testing or
security fixes from ISC. For current information on which versions are actively
supported, please see http://www.isc.org/software/bind/versions

CVSS Score: 7.8

CVSS Equation: (AV:N/AC:L/Au:N/C:N/I:N/A:C)

For more information on the Common Vulnerability Scoring System and to obtain
your specific environmental score please visit:

http://nvd.nist.gov/cvss.cfm?calculator&adv&version=2&vector=%28AV:N/AC:L/Au:N/C:N/I:N/A:C%29

Workarounds: None

Solution:
Upgrade to the patched release most closely related to your current version of 
BIND. These can all be downloaded from www.isc.org/downloads/all

    BIND 9 version 9.9.1-P2
    BIND 9 version 9.8.3-P2
    BIND 9 version 9.7.6-P2
    BIND 9 version 9.6-ESV-R7-P2

Exploit Status: None known at this time

Acknowledgment: ISC would like to thank Einar Lonn of IIS.se

Document Revision History:

    1.0 - 11 July, 2012 Phase 1 notice sent

    1.1 - 17 July, 2012 Phase 1 re-issued due to change in patch for
    CVE-2012-3868 that affects 9.9.x only

    1.2 - 23 July, 2012 Phase 2 & 3 sent

    2.0 - 24 July, 2012 Phase 3 (Public) notified

References:

- - Do you have Questions? Questions regarding this advisory should go to
security-officer@isc.org.

- - ISC Security Vulnerability Disclosure Policy: Details of our current security
advisory policy and practice can be found here:
https://www.isc.org/security-vulnerability-disclosure-policy

- - Japanese Translation:  https://kb.isc.org/article/AA-00752

- - Spanish Translation: https://kb.isc.org/article/AA-00750

- - German Translation:  https://kb.isc.org/article/AA-00743

This security advisory is also located in our KnowledgeBase:
https://deepthought.isc.org/Article/AA-00729

See our BIND Security Matrix for a complete listing of Security Vulnerabilites
and versions affected.

Note: ISC patches only Currently supported versions. When possible we indicate
EOL versions affected.

If you'd like more information on our Forum or BIND/DHCP support please visit
www.isc.org/software/guild or www.isc.org/support

Legal Disclaimer:

Internet Systems Consortium (ISC) is providing this notice on an "AS IS" basis.
No warranty or guarantee of any kind is expressed in this notice and none
should be inferred. ISC expressly excludes and disclaims any warranties
regarding this notice or materials referred to in this notice, including,
without limitation, any inferred warranty of merchantability, fitness for a
particular purpose, absence of hidden defects, or of non-infringement. Your use
of, or reliance on, this notice or materials referred to in this notice is at
your own risk. ISC may change this notice at any time.

A stand-alone copy or paraphrase of the text of this document that omits the
distribution URL in the following section is an uncontrolled copy. Uncontrolled
copies may lack important information, be out of date, or contain factual
errors.

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