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Ubuntu Security Notice USN-6588-2
March 26, 2024

pam vulnerability

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:

PAM could be made to stop responding if it opened a specially crafted file.

Software Description:

• pam: Pluggable Authentication Modules

Details:

USN-6588-1 fixed a vulnerability in PAM. This update
provides the corresponding updates for Ubuntu 14.04 LTS,
Ubuntu 16.04 LTS, and Ubuntu 18.04 LTS.

Original advisory details:

Matthias Gerstner discovered that the PAM pam_namespace module incorrectly
handled special files when performing directory checks. A local attacker
could possibly use this issue to cause PAM to stop responding,
resulting in
a denial of service.

Update instructions:

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

Ubuntu 18.04 LTS (Available with Ubuntu Pro):
libpam-modules 1.1.8-3.6ubuntu2.18.04.6+esm1

Ubuntu 16.04 LTS (Available with Ubuntu Pro):
libpam-modules 1.1.8-3.2ubuntu2.3+esm5

Ubuntu 14.04 LTS (Available with Ubuntu Pro):
libpam-modules 1.1.8-1ubuntu2.2+esm4

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

References:
https://ubuntu.com/security/notices/USN-6588-2
https://ubuntu.com/security/notices/USN-6588-1
CVE-2024-22365