Account Creation and Management

Cybersecurity Linux Lesson 2.2.2

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Account Creation and Configuration

Creation of a user leads to several actions and configurations to create a secure environment tailored to the user’s needs.
• Typically, a Linux system will run a series of shell commands in Bash upon startup.
• The system’s shell acts as an interpreter between the user and the operating system, reading startup configs and inputs.

Account Authentication

Prior to Bash running setup and configuration commands a user must be authenticated on the system
• The passwd command is used when adding a user and setting up their password
• The command can also be used to view password statues, set expirations, and more

Password Directives

• Along with the passwd command, the chage command can be used to change the expiration details of a user such as the age , expiration warning parameters, and the account expiration date
• The /etc/login.defs file is associated with an account when created and sets password directives

Failed Login Attempts

• The pam_tally2 and faillock utilities allow viewing and managing failed login attempts such as locking an account after so many attempts

Data Associated with Authentication

• System users and accounts created by applications are stored in the /etc/passwd file
• Information includes: • Username
• User and group ID
• Home directories
• Default shell used ` • The /etc/group file will store similar data, but with groups instead • In the past, passwords were also stored in the /etc/passwd file; however, that has changed to now being stored in the /etc/shadow file, or the /etc/gshadow for group information
• The password will not appear in plaintext, but is instead shown in a salted, hashed format

Environment Configuration

• The /etc/profile file is read when a user logs in and sets up the initial environment, such as system paths, shell prompts, aliases, and other functions • /etc/skel is a directory that contains files and directories that are copied when an account is created
• When the account is created, these provide the user with a pre-configured, or default, environment

Bash Configuration

• .bash_profile is initially executed upon logging in to setup the behavior and environment for the Bash shell
• The .bashrc file has the same purpose but is applied immediately and only requires relaunching the terminal