IMPORTANT: The security issue described below has been confirmed by ISC
to be 'in the wild' as of 18:00UTC July 26, and exploitation of this
vulnerability against production servers has been reported by multiple
organizations. Please be advised that immediate action is recommended.
A specially crafted query can cause BIND to terminate
CVE: CVE-2013-4854
Document Version: 2.0
Posting date: 26 July 2013
Program Impacted: BIND
Versions affected: Open source: 9.7.0->9.7.7, 9.8.0->9.8.5-P1,
9.9.0->9.9.3-P1, 9.8.6b1 and 9.9.4b1;
Subscription: 9.9.3-S1 and 9.9.4-S1b1
Severity: Critical
Exploitable: Remotely
Description:
A specially crafted query that includes malformed rdata can cause
named to terminate with an assertion failure while rejecting the
malformed query.
BIND 9.6 and BIND 9.6-ESV are unaffected by this problem. Earlier
branches of BIND 9 are believed to be unaffected but have not
been tested. BIND 10 is also unaffected by this issue.
Please Note: All versions of BIND 9.7 are known to be 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
http://www.isc.org/downloads/software-support-policy/bind-software-status/.
Impact:
Authoritative and recursive servers are equally vulnerable.
Intentional exploitation of this condition can cause a denial
of service in all nameservers running affected versions of BIND
9. Access Control Lists do not provide any protection from
malicious clients.
In addition to the named server, applications built using libraries
from the affected source distributions may crash with assertion
failures triggered in the same fashion.
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 visit:
http://nvd.nist.gov/cvss.cfm?calculator&adv&version=2&vector=(AV:N/AC:L/Au:N/C:N/I:N/A:C)
Workarounds:
No known workarounds at this time.
Active exploits:
Crashes have been reported by multiple ISC customers. First
observed in the wild on 26 July 2013, 18:00 UTC.
Solution:
Upgrade to the patched release most closely related to your
current version of BIND. Open source versions can all be
downloaded from
http://www.isc.org/downloads. Subscription
version customers will be contacted directly by ISC Support
regarding delivery.
BIND 9 version 9.8.5-P2
BIND 9 version 9.9.3-P2
BIND 9 version 9.9.3-S1-P1 (Subscription version available via DNSco)
Acknowledgements:
ISC would like to thank Maxim Shudrak and the HP Zero Day
Initiative for reporting this issue.
Document Revision History:
1.0 Phase One Advance Notification, 18 July 2013
1.1 Phases Two and Three Advance Notification, 26 July 2013
2.0 Notification to public (Phase Four), 26 July 2013
Related Documents:
Spanish Translation: planned
Japanese Translation:
https://kb.isc.org/article/AA-01023
Portuguese Translation:
https://kb.isc.org/article/AA-01021
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-01016
provides additional information and Frequently Asked Questions about
this advisory.
If you'd like more information on our product support or about our
Subscription versions of BIND, please visit
http://www.dns-co.com/solutions
Do you still have questions? Questions regarding this advisory
should go to
[email protected]. To report a new issue,
please encrypt your message using
[email protected]'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-01015
is the complete and official security advisory document.
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Uncontrolled copies may lack important information, be out of
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