==========================================================================
Ubuntu Security Notice USN-6633-1
February 13, 2024

bind9 vulnerabilities
==========================================================================

A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 23.10
- Ubuntu 22.04 LTS

Summary:

Several security issues were fixed in Bind.

Software Description:
- bind9: Internet Domain Name Server

Details:

Shoham Danino, Anat Bremler-Barr, Yehuda Afek, and Yuval Shavitt discovered
that Bind incorrectly handled parsing large DNS messages. A remote attacker
could possibly use this issue to cause Bind to consume resources, leading
to a denial of service. (CVE-2023-4408)

Elias Heftrig, Haya Schulmann, Niklas Vogel, and Michael Waidner discovered
that Bind icorrectly handled validating DNSSEC messages. A remote attacker
could possibly use this issue to cause Bind to consume resources, leading
to a denial of service. (CVE-2023-50387)

It was discovered that Bind incorrectly handled preparing an NSEC3 closest
encloser proof. A remote attacker could possibly use this issue to cause
Bind to consume resources, leading to a denial of service. (CVE-2023-50868)

It was discovered that Bind incorrectly handled reverse zone queries when
nxdomain-redirect is enabled. A remote attacker could possibly use this
issue to cause Bind to crash, leading to a denial of service.
(CVE-2023-5517)

It was discovered that Bind incorrectly handled recursive resolution when
both DNS64 and serve-stable were enabled. A remote attacker could possibly
use this issue to cause Bind to crash, leading to a denial of service.
(CVE-2023-5679)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 23.10:
   bind9                           1:9.18.18-0ubuntu2.1

Ubuntu 22.04 LTS:
   bind9                           1:9.18.18-0ubuntu0.22.04.2

In general, a standard system update will make all the necessary changes.

References:
   https://ubuntu.com/security/notices/USN-6633-1
   CVE-2023-4408, CVE-2023-50387, CVE-2023-50868, CVE-2023-5517,
   CVE-2023-5679

Package Information:
   https://launchpad.net/ubuntu/+source/bind9/1:9.18.18-0ubuntu2.1
   https://launchpad.net/ubuntu/+source/bind9/1:9.18.18-0ubuntu0.22.04.2