Knowledge Base ISC Main Website Ask a Question/Contact ISC
CVE-2011-0414: BIND -- Server Lockup Upon IXFR or DDNS Update Combined With High Query Rate
Author: Michael McNally Reference Number: AA-00461 Views: 4394 Created: 2011-09-09 23:26 Last Updated: 2012-06-08 11:33 0 Rating/ Voters

When an authoritative server processes a successful IXFR transfer or a dynamic update, there is a small window of time during which the IXFR/update coupled with a query may cause a deadlock to occur.
CERT
VU#559980
Document Version: 
1.1
Posting date: 
22 Feb 2011
Program Impacted: 
BIND
Versions affected: 
9.7.1-9.7.2-P3
Severity: 
High
Exploitable: 
remotely
Description: 

When an authoritative server processes a successful IXFR transfer or a dynamic update, there is a small window of time during which the IXFR/update coupled with a query may cause a deadlock to occur. This deadlock will cause the server to stop processing all requests. A high query rate and/or a high update rate will increase the probability of this condition.

CVSS Score: 7.1 (AV:N/AC:M/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

Workarounds: 

Depending on your performance requirements, a work-around may be available. ISC was not able to reproduce this defect in 9.7.2 using -n1, which causes named to use only one worker thread, thus avoiding the deadlock. If your server is powerful enough to serve your data with a single processor, this option may be fast to implement until you have time to perform an upgrade.

Active exploits: 
None known, but a description of the issue is available in the release notes for BIND 9.6.3 and 9.7.3.
Solution: 

If you run BIND 9.7.1 or 9.7.2, upgrade to BIND 9.7.3. Earlier versions are not vulnerable. If you run BIND 9.6.x, 9.6-ESV-Rx, or 9.4-ESV-R4, you do not need to upgrade.
BIND 9.5 is End of Life and is not supported by ISC. BIND 9.8 is not vulnerable.

Credits: Thank you to Neustar for finding the initial defect and JPRS for further testing and analysis.

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

Do you need Software Support? Questions on ISC's Support services or other offerings should be sent to sales@isc.org. More information on ISC's support and other offerings are available at: http://www.isc.org/community/blog/201102/BIND-support

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 security advisory is a copy of the official document located on our website: https://www.isc.org/software/bind/advisories/cve-2011-0414


© 2001-2015 Internet Systems Consortium

Please 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.

Feedback
  • There is no feedback for this article
Info Submit Feedback on this Article
Nickname: Your Email: Subject: Comment:
Enter the code below:
Quick Jump Menu