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CVE-2009-0696: BIND Dynamic Update DoS
Author: Cathy Almond Reference Number: AA-00926 Views: 2239 Created: 2013-05-23 17:14 Last Updated: 2013-05-23 17:14 0 Rating/ Voters
BIND denial of service (server crash) caused by receipt of a specific remote dynamic update message.

Posting date: 
28 Jul 2009
Program Impacted: 
BIND
Versions affected: 
BIND 9 (all versions)
Severity: 
High
Exploitable: 
Remotely

Description:

Urgent: this exploit is public. Please upgrade immediately.

Receipt of a specially-crafted dynamic update message to a zone for which the server is the master may cause BIND 9 servers to exit. Testing indicates that the attack packet has to be formulated against a zone for which that machine is a master. Launching the attack against slave zones does not trigger the assert.

This vulnerability affects all servers that are masters for one or more zones – it is not limited to those that are configured to allow dynamic updates. Access controls will not provide an effective workaround.

dns_db_findrdataset() fails when the prerequisite section of the dynamic update message contains a record of type “ANY” and where at least one RRset for this FQDN exists on the server:

db.c:659: REQUIRE(type != ((dns_rdatatype_t)dns_rdatatype_any)) failed
exiting (due to assertion failure).

Workarounds:

None.

(Some sites may have firewalls that can be configured with packet filtering techniques to prevent nsupdate messages from reaching their nameservers.)

Active exploits:

An active remote exploit is in wide circulation at this time

Solution:

Upgrade BIND to one of 9.4.3-P3, 9.5.1-P3 or 9.6.1-P1. These versions can be downloaded from:

Acknowledgements:

Matthias Urlichs for reporting the problem.
Tom Daly for methodical follow-on testing.

Document Revision History:

2009-07-28 Initial text
2009-07-29 Update to reflect Tom Daly's findings

Related Documents:

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

If you'd like more information on our Forum or product support please visit www.isc.org/support.

Do you still have questions?  Questions regarding this advisory should go to security-officer@isc.org

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: https://www.isc.org/security-vulnerability-disclosure-policy

This Knowledge Base article https://kb.isc.org/article/AA-00926 is the complete and official security advisory document.

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