Ubuntu 24.04 LTS default filesystem permissions must be defined in such a way that all authenticated users can read and modify only their own files.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-270716	SRG-OS-000480-GPOS-00228	UBTU-24-300030	SV-270716r1066637_rule	2025-02-18	1

Description
Setting the most restrictive default permissions ensures that when new accounts are created, they do not have unnecessary access.

ℹ️ Check
Verify Ubuntu 24.04 LTS defines default permissions for all authenticated users in such a way that the user can read and modify only their own files with the following command: $ grep -i '^\s*umask' /etc/login.defs UMASK 077 If the "UMASK" variable is set to "000", this is a finding with the severity raised to a CAT I. If the value of "UMASK" is not set to "077", is commented out, or is missing, this is a finding.

ℹ️ Check

Verify Ubuntu 24.04 LTS defines default permissions for all authenticated users in such a way that the user can read and modify only their own files with the following command: $ grep -i '^\s*umask' /etc/login.defs UMASK 077 If the "UMASK" variable is set to "000", this is a finding with the severity raised to a CAT I. If the value of "UMASK" is not set to "077", is commented out, or is missing, this is a finding.

✔️ Fix
Configure the system to define the default permissions for all authenticated users in such a way that the user can read and modify only their own files. Edit the "UMASK" parameter in the "/etc/login.defs" file to match the example below: UMASK 077