Security Advisory: Server Lockup Upon IXFR or DDNS Update Combined with High Query Rate

[Takuya Matsumoto]

Hi,

Does “a successful IXFR transfer” include “AXFR-style IXFR” ?

Thanks,
T. Matsumoto


From: bind-users-bounces+tmatsumo=yahoo-corp.jp at lists.isc.org [mailto:bind-users-bounces+tmatsumo=yahoo-corp.jp at lists.isc.org] On Behalf Of Larissa Shapiro
Sent: Wednesday, February 23, 2011 5:56 AM
To: bind-users at lists.isc.org
Subject: Security Advisory: Server Lockup Upon IXFR or DDNS Update Combined with High Query Rate


                                    Internet Systems Consortium Security Advisory

Title: Server Lockup Upon IXFR or DDNS Update Combined with High Query Rate

(http://www.isc.org/software/bind/advisories/cve-2011-0414)

CVE-2011-0414

VU#559980

CVSS: 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

Posting date: 2011-02-22

Program Impacted: BIND

Versions affected: 9.7.1-9.7.2-P3

Severity: High

Exploitable: Remotely

Description and Impact:

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.

Workaround:

Depending on your performance requirements, a work-around may be available. ISC was not able to reproduce this defect in 9.7.2 using -n 1, 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-R?, 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.

Questions regarding this advisory or ISC's Support services should be sent to bind9-bugs at isc.org<mailto:bind9-bugs at isc.org>
For more information on ISC's support, consulting, training, and other services, visit
http://www.isc.org/community/blog/201102/open-source-software-unsupported-isnt-it
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