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Ubuntu Security Notice USN-6183-2
July 18, 2023

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

- Ubuntu 18.04 LTS (Available with Ubuntu Pro)
- Ubuntu 16.04 LTS (Available with Ubuntu Pro)
- Ubuntu 14.04 LTS (Available with Ubuntu Pro)

Summary:

Bind could be made to crash if it received specially crafted network traffic.

Software Description:
- bind9: Internet Domain Name Server

Details:

USN-6183-1 fixed vulnerabilities in Bind. This update provides the
corresponding updates for Ubuntu 14.04 LTS, Ubuntu 16.04 LTS and Ubuntu 18.04
LTS.

Original advisory details:

  Shoham Danino, Anat Bremler-Barr, Yehuda Afek, and Yuval Shavitt discovered
  that Bind incorrectly handled the cache size limit. A remote attacker could
  possibly use this issue to consume memory, leading to a denial of service.
  (CVE-2023-2828)

  It was discovered that Bind incorrectly handled the recursive-clients
  quota. A remote attacker could possibly use this issue to cause Bind to
  crash, resulting in a denial of service. This issue only affected Ubuntu
  22.04 LTS, Ubuntu 22.10, and Ubuntu 23.04. (CVE-2023-2911)

Update instructions:

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

Ubuntu 18.04 LTS (Available with Ubuntu Pro):
   bind9                           1:9.11.3+dfsg-1ubuntu1.19+esm1

Ubuntu 16.04 LTS (Available with Ubuntu Pro):
   bind9 1:9.10.3.dfsg.P4-8ubuntu1.19+esm6

Ubuntu 14.04 LTS (Available with Ubuntu Pro):
   bind9                           1:9.9.5.dfsg-3ubuntu0.19+esm10

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

References:
   https://ubuntu.com/security/notices/USN-6183-2
   https://ubuntu.com/security/notices/USN-6183-1
   CVE-2023-2828