Security Advisory: Server Lockup Upon IXFR or DDNS Update Combined with High Query Rate
tmatsumo at yahoo-corp.jp
Wed Feb 23 06:45:13 UTC 2011
Does “a successful IXFR transfer” include “AXFR-style IXFR” ?
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
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
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.
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
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