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V-260555

CAT II (Medium)

Ubuntu 22.04 LTS default filesystem permissions must be defined in such a way that all authenticated users can read and modify only their own files.

Rule ID

SV-260555r991590_rule

STIG

Canonical Ubuntu 22.04 LTS Security Technical Implementation Guide

Version

V2R8

CCIs

CCI-000366

Discussion

Setting the most restrictive default permissions ensures newly created accounts do not have unnecessary access.

Check Content

Verify Ubuntu 22.04 LTS defines default permissions for all authenticated users in such a way that the user can read and modify only their own files by using 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 "UMASK" is not set to "077", is commented out, or is missing, this is a finding.

Fix Text

Configure Ubuntu 22.04 LTS to define the default permissions for all authenticated users in such a way that the user can read and modify only their own files.  
 
Add or modify the following line in the "/etc/login.defs" file:  
 
UMASK 077