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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2012.1132 A specific query can cause BIND nameservers using DNS64 to exit with a REQUIRE assertion failure. 5 December 2012 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: BIND Publisher: ISC Operating System: UNIX variants (UNIX, Linux, OSX) Windows Impact/Access: Denial of Service -- Remote/Unauthenticated Resolution: Patch/Upgrade CVE Names: CVE-2012-5688 Original Bulletin: https://kb.isc.org/article/AA-00828 - --------------------------BEGIN INCLUDED TEXT-------------------- A specific query can cause BIND nameservers using DNS64 to exit with a REQUIRE assertion failure. CVE: CVE-2012-5688 Document Version: 2.0 Posting date: 04 Dec 2012 Program Impacted: BIND Versions affected: 9.8.0->9.8.4, 9.9.0->9.9.2 Severity: Critical Exploitable: Remotely Description: BIND 9 nameservers using the DNS64 IPv6 transition mechanism are vulnerable to a software defect that allows a crafted query to crash the server with a REQUIRE assertion failure. Remote exploitation of this defect can be achieved without extensive effort, resulting in a denial-of-service (DoS) vector against affected servers. Please Note: Support for DNS64 was added to BIND 9 in version 9.8.0. Therefore BIND 9 versions prior to 9.8.0 cannot be affected by this bug. Also, nameservers running versions 9.8.0 and greater can only be affected if DNS64 is turned on using the "dns64" configuration statement. If you are not using DNS64 you are not at risk. For current information on which versions are actively supported, please see http://www.isc.org/software/bind/versions. Impact: Any BIND 9 nameserver configured to use DNS64 is vulnerable to this defect and can be crashed by any client machine from which it accepts queries. 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=(AV:N/AC:L/Au:N/C:N/I:N/A:C) Workarounds: Only BIND 9 servers which are configured to use DNS64 are vulnerable. For those servers, disallowing queries from untrusted clients (a recommended practice in any case) will slightly mitigate a server's exposure, but no workarounds are available which will completely protect an affected server against exploitation of this bug. If you are using DNS64 either disable it or upgrade to a fixed version. Active exploits: No known active exploits. Solution: Upgrade to the patched release most closely related to your current version of BIND. These can all be downloaded from http://www.isc.org/downloads/all. BIND 9 version 9.8.4-P1 BIND 9 version 9.9.2-P1 Acknowledgements: ISC would like to thank BlueCat Networks for bringing this defect to our attention. Document Revision History: 1.0 - 27 November 2012 Advance Notification to Phase One. 1.1 - 03 December 2012 Notification to Phase Two and Phase Three 2.0 - 04 December 2012 Notification to Phase Four (Public) Related Documents: Japanese Translation: https://kb.isc.org/article/AA-00832 Spanish Translation: https://kb.isc.org/article/AA-00834 German Translation: https://kb.isc.org/article/AA-00833 See our BIND Security Matrix for a complete listing of Security Vulnerabilities and versions affected. http://www.isc.org/software/bind/security/matrix If you'd like more information on our Forum or product support please visit www.isc.org/software/guild or www.isc.org/support. Do you still 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 This Knowledge Base article https://kb.isc.org/article/AA-00828 is the complete and official security advisory document. There is also a summary article located on our website and linking to here: https://www.isc.org/software/bind/advisories/cve-2012-5688 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 implied. ISC expressly excludes and disclaims any warranties regarding this notice or materials referred to in this notice, including, without limitation, any implied warranty of merchantability, fitness for a particular purpose, absence of hidden defects, or of non-infringement. Your use 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 document URL is an uncontrolled copy. Uncontrolled copies may lack important information, be out of date, or contain factual errors. (c) 2001-2012 Internet Systems Consortium - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. If you do not know who that is, please send an email to auscert@auscert.org.au and we will forward your request to the appropriate person. NOTE: Third Party Rights This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. The decision to follow or act on information or advice contained in this security bulletin is the responsibility of each user or organisation, and should be considered in accordance with your organisation's site policies and procedures. AusCERT takes no responsibility for consequences which may arise from following or acting on information or advice contained in this security bulletin. NOTE: This is only the original release of the security bulletin. It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the author's website to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: http://www.auscert.org.au/render.html?cid=1980 =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for member emergencies only. =========================================================================== -----BEGIN PGP SIGNATURE----- Comment: http://www.auscert.org.au/render.html?it=1967 iQIVAwUBUL6Tbu4yVqjM2NGpAQLxmRAAvq5mIk2jiyMNv9a+Rofs2yNlPmF9KAG3 87tdH7sRjh2RTyoy70TnU/GOTIJV0zZOmgMPf4T9+5l87+kdLdwxeJZHpZIEIUy/ uuGDYeNcwOIOIXe5PddNSwNiC0e9eepyboVij84sytBKOYzg1CzRzCFHWT5zDklJ miTQ6WqMYwSRgjzLj0TZ9sBdfS8RVuTtDHxMCVf9vPcqNU10kjfbzzKjUGiZ4zUZ E51CRAxr2lmjyP/krXej/lESgqVro41i5NyKvZ6TtAPJVyfOgEUVvxx9rVyMVSWJ djl/NQOG0yy4rqMouJoKpNd7lTt0VCjHEpVKiP4jbIY9EWCrsVlOjH6HBaaONRuA nb9k1XhLr+miarxo4sNkBy4FtIiBHarJYLYNvRlpof1i7QX7vJE5kFf24pog/+ns wupYzYSzahbOMymRpaaKLJLe6hHXWL8SOeHJf3LGh4W1KqCTyye2mpY6BC2Pjy2K NBRzU1yImORxBVgFX4dTwi27PFb6hxDicx+FPT02LOk2BkE06qi9nqolgSUNBw79 IHwTbtZ/MnhNBgPnhXQtBDSEwZYh9FImOoiIQhpmn+SfWRrPGxfwjMLRufSTYzCh QbsHyrvD4piohf/cZIpq5OoIRixrwK63hSLgdnNFMxhZVrVjJXybWlhI78PrzXId nz+eEe+tF2c= =cN6Z -----END PGP SIGNATURE-----