A PAM security update has been released for Ubuntu Linux 14.04 ESM, 16.04 ESM, 18.04 LTS, 20.04 LTS, 22.04 LTS, and 22.10.

USN-5825-1: PAM vulnerability

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Ubuntu Security Notice USN-5825-1
January 25, 2023

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

- Ubuntu 22.10
- Ubuntu 22.04 LTS
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 ESM
- Ubuntu 14.04 ESM

Summary:

PAM would allow unintended access to the machine over network.

Software Description:
- pam: Pluggable Authentication Modules

Details:

It was discovered that PAM did not correctly restrict login from an IP
address that is not resolvable via DNS. An attacker could possibly use this
issue to bypass authentication.

Update instructions:

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

Ubuntu 22.10:
libpam-modules 1.5.2-2ubuntu1.1

Ubuntu 22.04 LTS:
libpam-modules 1.4.0-11ubuntu2.1

Ubuntu 20.04 LTS:
libpam-modules 1.3.1-5ubuntu4.4

Ubuntu 18.04 LTS:
libpam-modules 1.1.8-3.6ubuntu2.18.04.4

Ubuntu 16.04 ESM:
libpam-modules 1.1.8-3.2ubuntu2.3+esm2

Ubuntu 14.04 ESM:
libpam-modules 1.1.8-1ubuntu2.2+esm1

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

References:
  https://ubuntu.com/security/notices/USN-5825-1
CVE-2022-28321

Package Information:
  https://launchpad.net/ubuntu/+source/pam/1.5.2-2ubuntu1.1
  https://launchpad.net/ubuntu/+source/pam/1.4.0-11ubuntu2.1
  https://launchpad.net/ubuntu/+source/pam/1.3.1-5ubuntu4.4
  https://launchpad.net/ubuntu/+source/pam/1.1.8-3.6ubuntu2.18.04.4