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CVE-2012-1667: Handling of zero length rdata can cause named to terminate unexpectedly
Author: Cathy Almond Reference Number: AA-00698 Views: 6156 Created: 2012-06-04 08:37 Last Updated: 2012-07-24 00:13 0 Rating/ Voters

Processing of DNS resource records where the rdata field is zero length may cause various issues for the servers handling them.

Document Version:          
Posting date: 
04 Jun 2012
Program Impacted: 
Versions affected: 
9.0.x -> 9.6.x, 9.4-ESV->9.4-ESV-R5-P1, 9.6-ESV->9.6-ESV-R7, 9.7.0->9.7.6, 9.8.0->9.8.3, 9.9.0->9.9.1


This problem was uncovered while testing with experimental DNS record types. It is possible to add records to BIND with null (zero length) rdata fields.

Processing of these records may lead to unexpected outcomes. Recursive servers may crash or disclose some portion of memory to the client. Secondary servers may crash on restart after transferring a zone containing these records. Master servers may corrupt zone data if the zone option "auto-dnssec" is set to "maintain". Other unexpected problems that are not listed here may also be encountered.

This issue primarily affects recursive nameservers. Authoritative nameservers will only be impacted if an administrator configures experimental record types with no data. If the server is configured this way, then secondaries can crash on restart after transferring that zone. Zone data on the master can become corrupted if the zone with those records has named configured to manage the DNSSEC key rotation.

CVSS Score: 8.5

CVSS Equation: (AV:N/AC:L/Au:N/C:P/I:N/A:C)

For more information on the Common Vulnerability Scoring System and to obtain your specific environmental score please visit:


Workarounds are under investigation, but none are known at this time.

Active exploits: 

No known active exploits but a public discussion of the issue has taken place on a public mailing list.


Upgrade to BIND version 9.6-ESV-R7-P1, 9.7.6-P1, 9.8.3-P1, or 9.9.1-P1

Acknowledgment: Dan Luther, Level3 Communications, for finding the issue, Jeffrey A. Spain, Cincinnati Day School, for replication and testing.

Document Revision History:

1.0 Released to Public 4 June, 2012

1.1 Updated Severity to Critical

1.2 Added German Translation 7 June, 2012

1.3 Added link to FAQ supplemental article in KB

1.4 Added Chinese Translation

Related Documents:

- Japanese Translation:

- Spanish Translation

- German Translation:

- Chinese Translation:

This security advisory is a copy of the official document located on our website:

See our BIND Security Matrix for a complete listing of Security Vulnerabilites and versions affected.

This new KnowledgBase article includes additional information and Frequently Asked Questions about this advisory.

Do you still have questions? Questions regarding this advisory should go to

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:

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