CVE-2012-1667: Handling of zero length rdata can cause named to terminate unexpectedly

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

CVE: CVE-2012-1667

Document version: 1.4

Posting date: 04 Jun 2012

Program impacted: BIND

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

Severity: Critical

Exploitable: Remotely

Description:

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.

Impact:

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: http://nvd.nist.gov/cvss.cfm?calculator&adv&version=2&vector=(AV:N/AC:L/Au:N/C:P/I:N/A:C).

Workarounds: 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.

Solution: 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:

- German Translation: http://cert.uni-stuttgart.de/ticker/article.php?mid=1694

- Chinese Translation: no longer available

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See our BIND 9 Security Vulnerability Matrix for a complete listing of security vulnerabilities and versions affected.

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