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Ubuntu Security Notice USN-5825-2
February 06, 2023

pam regressions

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:

USN-5825-1 caused some minor regressions in PAM.

Software Description:

• pam: Pluggable Authentication Modules

Details:

USN-5825-1 fixed vulnerabilities in PAM. Unfortunately that update was
incomplete and could introduce a regression. This update fixes the problem.

We apologize for the inconvenience.

Original advisory 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 1.5.2-2ubuntu1.3

Ubuntu 22.04 LTS:
libpam-modules 1.4.0-11ubuntu2.3

Ubuntu 20.04 LTS:
libpam-modules 1.3.1-5ubuntu4.6

Ubuntu 18.04 LTS:
libpam-modules 1.1.8-3.6ubuntu2.18.04.6

Ubuntu 16.04 ESM:
libpam-modules 1.1.8-3.2ubuntu2.3+esm4

Ubuntu 14.04 ESM:
libpam-modules 1.1.8-1ubuntu2.2+esm3

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

References:
https://ubuntu.com/security/notices/USN-5825-2
https://ubuntu.com/security/notices/USN-5825-1
CVE-2022-28321, https://launchpad.net/bugs/2006073

Package Information:
https://launchpad.net/ubuntu/+source/pam/1.5.2-2ubuntu1.3
https://launchpad.net/ubuntu/+source/pam/1.4.0-11ubuntu2.3
https://launchpad.net/ubuntu/+source/pam/1.3.1-5ubuntu4.6
https://launchpad.net/ubuntu/+source/pam/1.1.8-3.6ubuntu2.18.04.6