--- title: "CVE-2009-0696: BIND Dynamic Update DoS" slug: "aa-00926" description: "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." updated: 2025-03-24T21:55:51Z published: 2025-03-24T21:55:51Z --- > ## Documentation Index > Fetch the complete documentation index at: https://kb.isc.org/llms.txt > Use this file to discover all available pages before exploring further. # CVE-2009-0696: BIND Dynamic Update DoS BIND denial of service (server crash) caused by receipt of a specific remote dynamic update message. CVE: [CVE-2009-0696](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-0696) [VU#725188](http://www.kb.cert.org/vuls/id/725188) Posting date: 28 Jul 2009 Program Impacted: [BIND](https://www.isc.org/software/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)) failedexiting (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: - [http://ftp.isc.org/isc/bind9/9.6.1-P1/bind-9.6.1-P1.tar.gz](http://ftp.isc.org/isc/bind9/9.6.1-P1/bind-9.6.1-P1.tar.gz) - [http://ftp.isc.org/isc/bind9/9.5.1-P3/bind-9.5.1-P3.tar.gz](http://ftp.isc.org/isc/bind9/9.5.1-P3/bind-9.5.1-P3.tar.gz) - [http://ftp.isc.org/isc/bind9/9.4.3-P3/bind-9.4.3-P3.tar.gz](http://ftp.isc.org/isc/bind9/9.4.3-P3/bind-9.4.3-P3.tar.gz) **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 2020-02-03 Update link to ISC's Security Policy **Related Documents:** See our [BIND Security Matrix](https://kb.isc.org/docs/aa-00913) 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](http://www.isc.org/support). **Do you still have questions?** Questions regarding this advisory should go to [security-officer@isc.org](mailto:security-officer@isc.org) **Note:** ISC patches only [currently supported versions](http://www.isc.org/software/bind/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://kb.isc.org/docs/aa-00861](https://kb.isc.org/docs/aa-00861) This Knowledge Base article [https://kb.isc.org/docs/aa-00926](https://kb.isc.org/docs/aa-00926) is the complete and official security advisory document. **Legal Disclaimer:** Internet Systems Consortium (ISC) is providing this notice on an "AS IS" basis. No warranty or guarantee of any kind is expressed in this notice and none should be implied. 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