CVE-2016-1284: A REQUIRE assertion failure in rdataset.c can be deliberately triggered in servers performing NXDOMAIN redirection
- Updated on 31 Oct 2018
- 3 minutes to read
Features which are created for BIND 9 Supported Preview Edition are ported to main-line open-source BIND releases after they have been refined in the Supported Preview Edition.
Document version: 1.0
Posting date: 3 February 2016
Program impacted: BIND 9 Supported Preview Edition (sometimes called "BIND 9 Subscription Edition")
Versions affected: 9.9.8-S1 -> 9.9.8-S4
An error in handling flag values in incoming queries can be exploited to deliberately trigger a REQUIRE assertion failure in rdataset.c on servers using the "nxdomain-redirect" option in BIND 9 Supported Preview Edition.
Servers configured for NXDOMAIN redirection using the "nxdomain-redirect" option are at risk from a constructed query with the right combination of attributes. Successful exploitation of this bug allows an attacker to cause a nameserver running BIND 9 Supported Preview Edition to stop execution after encountering a REQUIRE assertion failure in rdataset.c, resulting in denial of service to clients.
Servers configured for NXDOMAIN redirection using a "type redirect" zone rather than the "nxdomain-redirect" option are not at risk.
The assertion failure logged is:
rdataset.c:147: REQUIRE(((rdataset) != ((void *)0)) && ((const isc__magic_t *)(rdataset)->magic == (('D') << 24 | ('N') << 16 | ('S') << 8 | ('R'))))
The underlying bug is an assignment of a flag value to the wrong variable; this bug has existed in all Supported Preview releases since 9.9.6-S1, but it was harmless prior to the introduction of the "nxdomain-redirect" option.
CVSS Score: 5.4
CVSS Vector: (AV:N/AC:H/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: https://nvd.nist.gov/cvss.cfm?calculator&version=2&vector=(AV:N/AC:H/Au:N/C:N/I:N/A:C).
Workarounds: Servers which do not use "nxdomain-redirect" are not at risk. Only servers using this feature of BIND 9 Supported Preview Edition are affected.
Active exploits: No known active exploits.
Solution: Choose one of the following two options:
- A patch which will apply to BIND 9 Supported Preview Edition version 9.9.8-S4 is available upon request.
- A correction for the defect is included in BIND 9 Supported Preview Edition version 9.9.8-S5.
Document Revision History:
1.0 Advance Notification. 27 January 2016
Related Documents: See our BIND 9 Security Vulnerability Matrix for a complete listing of Security Vulnerabilities and versions affected.
If you'd like more information on ISC Subscription Support and Advance Security Notifications, please visit https://www.isc.org/support/.
Do you still have questions? Questions regarding this advisory should go to firstname.lastname@example.org. To report a new issue, please encrypt your message using email@example.com's PGP key which can be found here: 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/.
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/).
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.
This Knowledgebase article is the complete and official security advisory document.
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.