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.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-270716 | UBTU-24-300030 | SV-270716r1066637_rule | Medium |
| Description |
| Setting the most restrictive default permissions ensures that when new accounts are created, they do not have unnecessary access. |
| STIG | Date |
| Canonical Ubuntu 24.04 LTS Security Technical Implementation Guide | 2025-05-16 |
Details
| Check Text (C-74749r1066635_chk) |
| 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 Text (F-74650r1066636_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 |