What This Document Is
This guide provides an overview of users and groups within a Linux operating system environment. It explains how these elements function as fundamental components of system security and access control. The document details the concepts of User IDs (UIDs) and Group IDs (GIDs), and how they relate to managing permissions for files, directories, and system resources.
Why This Document Matters
This document is essential for anyone studying introductory information security, particularly within a Linux context (like Columbus State University’s CYBR 2160 course). Understanding users and groups is a foundational step toward comprehending more complex security principles. It’s relevant when setting up user accounts, managing file permissions, and ensuring secure system administration. This knowledge is crucial for anyone who will be working with or administering Linux systems.
Common Limitations or Challenges
This document serves as an introductory guide. It does *not* provide exhaustive coverage of all Linux user and group management tools or advanced security configurations. It won’t cover scripting or automation of user/group administration. Practical, in-depth troubleshooting scenarios are also beyond its scope.
What This Document Provides
The full document includes:
* Definitions of users, groups, UID, and GID.
* An explanation of primary and secondary groups.
* Details on the ‘root’ superuser and privilege escalation using `su` and `sudo`.
* Commands for adding and deleting users and groups (`adduser`, `useradd`, `addgroup`).
* Commands for viewing user and group information (`cat /etc/passwd`, `id`).
* Instructions for modifying user group memberships (`usermod`).
* An overview of the `/etc/passwd` and `/etc/shadow` files and their associated permissions.
* Discussion of access control mechanisms at various layers (physical, network, host, application).
* An explanation of identification vs. authentication and different authentication factors.