The Ubuntu operating system 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-238209 | UBTU-20-010016 | SV-238209r991590_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 20.04 LTS Security Technical Implementation Guide | 2024-08-22 |
Details
| Check Text (C-41419r653800_chk) |
| Verify the Ubuntu operating system defines default permissions for all authenticated users in such a way that the user can read and modify only their own files. Verify the Ubuntu operating system defines default permissions for all authenticated users with the following command: $ grep -i "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 completely, this is a finding. |
| Fix Text (F-41378r653801_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 |