Reachable Assertion in ISC BIND - CVE-2019-6467

Detailed vulnerability description

The vulnerability allows a remote non-authenticated attacker to perform a denial of service (DoS) attack.

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. Versions affected: BIND 9.12.0-> 9.12.4, 9.14.0. Also affects all releases in the 9.13 development branch.

How to mitigate CVE-2019-6467

Sources

• https://kb.isc.org/docs/cve-2019-6467
• https://www.synology.com/security/advisory/Synology_SA_19_20