Amazon Linux 2023 must define default permissions for all authenticated users in such a way that the user can only read and modify their own files.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-274145	SRG-OS-000480-GPOS-00228	AZLX-23-002410	SV-274145r1120423_rule	2025-07-15	1

Description
Setting the most restrictive default permissions ensures that when new accounts are created, they do not have unnecessary access. Satisfies: SRG-OS-000480-GPOS-00228, SRG-OS-000480-GPOS-00230

ℹ️ Check
Verify Amazon Linux 2023 defines default permissions for all authenticated users in such a way that the user can only read and modify their own files with the following command: Note: If the value of the "UMASK" parameter is set to "000" in "/etc/login.defs" file, the Severity is raised to a CAT I. # grep -i umask /etc/login.defs UMASK 077 If the value for the "UMASK" parameter is not "077", or the "UMASK" parameter is missing or is commented out, this is a finding.

ℹ️ Check

Verify Amazon Linux 2023 defines default permissions for all authenticated users in such a way that the user can only read and modify their own files with the following command: Note: If the value of the "UMASK" parameter is set to "000" in "/etc/login.defs" file, the Severity is raised to a CAT I. # grep -i umask /etc/login.defs UMASK 077 If the value for the "UMASK" parameter is not "077", or the "UMASK" parameter is missing or is commented out, this is a finding.

✔️ Fix
Configure Amazon Linux 2023 to define default permissions for all authenticated users in such a way that the user can only read and modify their own files. Add or edit the lines for the "UMASK" parameter in the "/etc/login.defs" file to "077": UMASK 077