ISC Security Advisory: Heavy DNSSEC Validation Load Can Cause a "Bad Cache" Assertion Failure in BIND9
cathya at isc.org
Tue Jul 24 17:45:07 UTC 2012
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Title: Heavy DNSSEC Validation Load Can Cause a "Bad Cache" Assertion
Failure in BIND9
Summary: High numbers of queries with DNSSEC validation enabled can
cause an assertion failure in named, caused by using a "bad cache" data
structure before it has been initialized.
Document Version: 2.0
Posting date: 24 July, 2012
Program Impacted: BIND 9
Versions affected: 9.6-ESV-R1 through 9.6-ESV-R7-P1; 9.7.1 through
9.7.6-P1; 9.8.0 through 9.8.3-P1; 9.9.0 through 9.9.1-P1.
BIND 9 stores a cache of query names that are known to be failing due to
misconfigured name servers or a broken chain of trust. Under high query
loads when DNSSEC validation is active, it is possible for a condition
to arise in which data from this cache of failing queries could be used
before it was fully initialized, triggering an assertion failure.
This bug cannot be encountered unless your server is doing DNSSEC
Please Note: Versions of BIND 9.4 and 9.5 are also affected, but these
branches are beyond their "end of life" (EOL) and no longer receive
testing or security fixes from ISC. For current information on which
versions are actively supported, please see
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
Solution: Upgrade to the patched release most closely related to your
current version of BIND. These can all be downloaded from
BIND 9 version 9.9.1-P2
BIND 9 version 9.8.3-P2
BIND 9 version 9.7.6-P2
BIND 9 version 9.6-ESV-R7-P2
Exploit Status: None known at this time
Acknowledgment: ISC would like to thank Einar Lonn of IIS.se
Document Revision History:
1.0 - 11 July, 2012 Phase 1 notice sent
1.1 - 17 July, 2012 Phase 1 re-issued due to change in patch for
CVE-2012-3868 that affects 9.9.x only
1.2 - 23 July, 2012 Phase 2 & 3 sent
2.0 - 24 July, 2012 Phase 3 (Public) notified
- Do you have Questions? Questions regarding this advisory should go to
security-officer at isc.org.
- ISC Security Vulnerability Disclosure Policy: Details of our current
security advisory policy and practice can be found here:
- Japanese Translation: https://kb.isc.org/article/AA-00752
- Spanish Translation: https://kb.isc.org/article/AA-00750
- German Translation: https://kb.isc.org/article/AA-00743
This security advisory is also located in our KnowledgeBase:
See our BIND Security Matrix for a complete listing of Security
Vulnerabilites and versions affected.
Note: ISC patches only Currently supported versions. When possible we
indicate EOL versions affected.
If you'd like more information on our Forum or BIND/DHCP support please
visit www.isc.org/software/guild or www.isc.org/support
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