CVE-2019-6467: An error in the nxdomain redirect feature can cause BIND to exit with an INSIST assertion failure in query.c
Document version: 2.0
Posting date: 24 April 2019
Program impacted: BIND
Versions affected: BIND 9.12.0-> 9.12.4, 9.14.0. Also affects all releases in the 9.13 development branch.
A programming error in the nxdomain-redirect feature can cause an assertion failure in query.c if the alternate namespace used by nxdomain-redirect is a descendant of a zone that is served locally.
The most likely scenario where this might occur is if the server, in addition to performing NXDOMAIN redirection for recursive clients, is also serving a local copy of the root zone or using mirroring to provide the root zone, although other configurations are also possible.
An attacker who can deliberately trigger the condition on a server with a vulnerable configuration can cause BIND to exit, denying service to other clients.
CVSS Score: 5.9
CVSS Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
For more information on the Common Vulnerability Scoring System and to obtain your specific environmental score please visit: https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.
Exploitation of this defect can be effectively prevented by disabling the nxdomain-redirect feature in the nameserver's configuration.
Upgrade to the patched release most closely related to your current version of BIND:
- BIND 9.12.4-P1
- BIND 9.14.1
Document revision history:
1.0 Early Notification, 15 April 2019
1.1 Removed BIND 9.11.6-P1 from Solution version list
2.0 Public Disclosure, 24 April 2019
See our BIND 9 Security Vulnerability Matrix for a complete listing of security vulnerabilities and versions affected.
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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/.)
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