--- title: "CVE-2013-3919: A recursive resolver can be crashed by a query for a malformed zone" slug: "aa-00967" description: "A bug has been discovered in the most recent releases of BIND 9 which has the potential for deliberate exploitation as a denial-of-service attack. By sending a recursive resolver a query for a record in a specially malformed zone, an attacker can cause BIND 9 to exit with a fatal \"RUNTIME_CHECK\" error in resolver.c." updated: 2018-12-06T20:59:02Z published: 2018-12-06T20:59:02Z canonical: "kb.isc.org/aa-00967" --- > ## 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-2013-3919: A recursive resolver can be crashed by a query for a malformed zone A defect exists which allows an attacker to crash a BIND 9 recursive resolver with a RUNTIME_CHECK error in resolver.c **CVE:** [CVE-2013-3919](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-3919) **Document version:** 1.1 **Posting date:** 04 Jun 2013 **Program impacted:** [BIND 9](https://www.isc.org/software/bind) **Versions affected:** BIND 9.6-ESV-R9, 9.8.5, and 9.9.3 are affected. Versions 9.6.0 through 9.6-ESV-R8, 9.8.0 through 9.8.4-P2, and 9.9.0 through 9.9.2-P2 ARE NOT affected. Other major branches of BIND (e.g. 9.7, 9.5, etc) are not vulnerable but they are no longer supported by ISC and may lack other important security fixes. **Severity:** High **Exploitable:** Remotely **Description:** A bug has been discovered in the most recent releases of BIND 9 which has the potential for deliberate exploitation as a denial-of-service attack. By sending a recursive resolver a query for a record in a specially malformed zone, an attacker can cause BIND 9 to exit with a fatal "RUNTIME_CHECK" error in `resolver.c`. **Impact:** Triggering this defect will cause the affected server to exit with an error, denying service to recursive DNS clients that use that particular server. **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=%28AV:N/AC:L/Au:N/C:N/I:N/A:C%29](http://nvd.nist.gov/cvss.cfm?calculator&adv&version=2&vector=(AV:N/AC:L/Au:N/C:N/I:N/A:C)). **Workarounds:** None. **Active exploits:** At the time of this advisory, no intentional exploitation of this bug has been observed in the wild. However, the existence of the issue has been disclosed on an open mailing list with enough accompanying detail to reverse-engineer an attack and ISC is therefore treating this as a Type II (publicly disclosed) vulnerability, in accordance with our Phased Disclosure Process. **Solution:** New versions of BIND are being provided which contain a fix for the defect. The recommended solution is to upgrade to the patched release most closely related to your current version of BIND. These can all be downloaded from [https://www.isc.org/downloads/bind](https://www.isc.org/downloads/bind). - BIND 9 version 9.9.3-P1 - BIND 9 version 9.8.5-P1 - BIND 9 version 9.6-ESV-R9-P1 **Acknowledgements:** **Document Revision History:** 1.0 Type II Public Disclosure, 04 June 2013 1.1 Published [FAQ and Supplemental Information](https://kb.isc.org/docs/aa-00997), 13 June 2013 **Related Documents:** If you'd like more information on ISC Subscription Support and Advance Security Notifications, please visit [https://www.isc.org/support/](https://www.isc.org/support). See our [BIND 9 Security Vulnerability Matrix](https://kb.isc.org/docs/aa-00913) for a complete listing of security vulnerabilities and versions affected. **Do you still have questions?** Questions regarding this advisory should go to [security-officer@isc.org](mailto:security-officer@isc.org). *To report a new issue, please encrypt your message using security-officer@isc.org's PGP key which can be found here: [https://www.isc.org/downloads/software-support-policy/openpgp-key/](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/community/report-bug/](https://www.isc.org/community/report-bug).* **Note:** ISC patches only currently supported versions. When possible, we indicate EOL versions affected. (For current information on which versions are actively supported, please see [https://www.isc.org/downloads/](https://www.isc.org/downloads).) **ISC Security Vulnerability Disclosure Policy:** Details of our current security advisory policy and practice can be found in the [ISC Software Defect and Security Vulnerability Disclosure Policy](https://kb.isc.org/docs/aa-00861). This [Knowledgebase article](https://kb.isc.org/docs/aa-00967) 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. ISC expressly excludes and disclaims any warranties regarding this notice or materials referred to in this notice, including, without limitation, any implied warranty of merchantability, fitness for a particular purpose, absence of hidden defects, or of non-infringement. Your use or reliance on this notice or materials referred to in this notice is at your own risk. ISC may change this notice at any time. A stand-alone copy or paraphrase of the text of this document that omits the document URL is an uncontrolled copy. Uncontrolled copies may lack important information, be out of date, or contain factual errors.