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.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-260555 | UBTU-22-412035 | SV-260555r991590_rule | Medium |
| Description |
| Setting the most restrictive default permissions ensures newly created accounts do not have unnecessary access. |
| STIG | Date |
| Canonical Ubuntu 22.04 LTS Security Technical Implementation Guide | 2025-05-16 |
Details
| Check Text (C-64284r953476_chk) |
| 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 (F-64192r953477_fix) |
| 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 |