=========================================================================Ubuntu Security Notice USN-4468-1
August 21, 2020

bind9 vulnerabilities
=========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

Several security issues were fixed in Bind.

Software Description:
- bind9: Internet Domain Name Server

Details:

Emanuel Almeida discovered that Bind incorrectly handled certain TCP
payloads. A remote attacker could possibly use this issue to cause Bind to
crash, resulting in a denial of service. This issue only affected Ubuntu
20.04 LTS. (CVE-2020-8620)

Joseph Gullo discovered that Bind incorrectly handled QNAME minimization
when used in certain configurations. A remote attacker could possibly use
this issue to cause Bind to crash, resulting in a denial of service. This
issue only affected Ubuntu 20.04 LTS. (CVE-2020-8621)

Dave Feldman, Jeff Warren, and Joel Cunningham discovered that Bind
incorrectly handled certain truncated responses to a TSIG-signed request. A
remote attacker could possibly use this issue to cause Bind to crash,
resulting in a denial of service. (CVE-2020-8622)

Lyu Chiy discovered that Bind incorrectly handled certain queries. A remote
attacker could possibly use this issue to cause Bind to crash, resulting in
a denial of service. (CVE-2020-8623)

Joop Boonen discovered that Bind incorrectly handled certain subdomain
update-policy rules. A remote attacker granted privileges to change certain
parts of a zone could use this issue to change other contents of the zone,
contrary to expectations. This issue only affected Ubuntu 18.04 LTS and
Ubuntu 20.04 LTS. (CVE-2020-8624)

Update instructions:

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

Ubuntu 20.04 LTS:
  bind9                           1:9.16.1-0ubuntu2.3

Ubuntu 18.04 LTS:
  bind9                           1:9.11.3+dfsg-1ubuntu1.13

Ubuntu 16.04 LTS:
  bind9                           1:9.10.3.dfsg.P4-8ubuntu1.17

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

References:
  https://ubuntu.com/security/notices/USN-4468-1
  CVE-2020-8620, CVE-2020-8621, CVE-2020-8622, CVE-2020-8623,
  CVE-2020-8624

Package Information:
  https://launchpad.net/ubuntu/+source/bind9/1:9.16.1-0ubuntu2.3
  https://launchpad.net/ubuntu/+source/bind9/1:9.11.3+dfsg-1ubuntu1.13
  https://launchpad.net/ubuntu/+source/bind9/1:9.10.3.dfsg.P4-8ubuntu1.17