An unintentional defect in the handling of NSEC3-signed zones can cause BIND to be crashed by a specific set of queries.
Posting date: 13 Jan 2014
9.6.0.x -> 9.6-ESV-R10-P1, 9.7 (all versions), 9.8.0 -> 9.8.6-P1, 9.9.0 -> 9.9.4-P1. Development releases 9.6-ESV-R11b1, 9.8.7b1, and 9.9.5b1 are also affected.
Because of a defect in handling queries for NSEC3-signed zones, BIND can crash with an "INSIST" failure in name.c when processing queries possessing certain properties. By exploiting this defect an attacker deliberately constructing a query with the right properties could achieve denial of service against an authoritative nameserver serving NSEC3-signed zones.
Please Note: Versions of BIND 9.7 are also affected, but this branch is beyond its "end of life" (EOL) and no longer receives testing or security fixes from ISC. For current information on which versions are actively supported, please see http://www.isc.org/downloads/software-support-policy/bind-software-status/.
Authoritative nameservers serving at least one NSEC3-signed zone are vulnerable to this defect. Recursive-only servers are not at risk. Authoritative servers which do not serve NSEC3-signed zones are not at risk.
CVSS Score: 5.4
CVSS Vector: (AV:N/AC:H/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:H/Au:N/C:N/I:N/A:C)
There are no known active exploits but limited discussion of this issue has taken place on a public mailing list.
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.
- BIND 9 version 9.6-ESV-R10-P2
- BIND 9 version 9.8.6-P2
- BIND 9 version 9.9.4-P2
Acknowledgements: ISC would like to thank Jared Mauch for reporting this issue.
Document Revision History:
1.0 Phase One, Advance Notification 06 January, 2014
1.1 Phase One+, Advance Notification 08 January, 2014
1.2 Phase Two & Three, Advance Notification 10 January, 2014
1.3 Changed CVSS Equation to Vector and edited Exploits 11 January, 2014
2.0 Phase Four, Public Release 13 January, 2014
See our BIND Security Matrix for a complete listing of Security Vulnerabilities and versions affected.
This Knowledge Base article https://kb.isc.org/article/AA-01085 provides additional information and Frequently Asked Questions about this advisory.
If you'd like more information on our ISC Member program please visit https://www.isc.org/members/, or product support please visit http://www.dns-co.com/solutions/.
Do you still have questions? Questions regarding this advisory should go to email@example.com. To report a new issue, please encrypt your message using firstname.lastname@example.org's PGP key which can be found here: https://www.isc.org/downloads/software-support-policy/openpgp-key/. If you are unable to use encrypted email, you may also report new issues at: https://www.isc.org/mission/contact/.
Note: ISC patches only currently supported versions. When possible we indicate EOL versions affected.
ISC Security Vulnerability Disclosure Policy: Details of our current security advisory policy and practice can be found here: ISC Software Defect and Security Vulnerability Disclosure Policy
This Knowledge Base article https://kb.isc.org/article/AA-01078/74/ is the complete and official security advisory document.
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.
© 2001-2015 Internet Systems ConsortiumPlease help us to improve the content of our knowledge base by letting us know below how we can improve this article. If you have a technical question or problem on which you'd like help, please don't submit it here as article feedback. For assistance with problems and questions for which you have not been able to find an answer in our Knowledge Base, we recommend searching our community mailing list archives and/or posting your question there (you will need to register there first for your posts to be accepted). The bind-users and the dhcp-users lists particularly have a long-standing and active membership.ISC relies on the financial support of the community to fund the development of its open source software products. If you would like to support future product evolution and maintenance as well having peace of mind knowing that our team of experts are poised to provide you with individual technical assistance whenever you call upon them, then please consider our Professional Subscription Support services - details can be found on our main website.