Linux Security Fundamentals: Level up your security skills

Explore how PAM handles authentication on Linux systems, from storing passwords and grouping to managing users and groups. Enforce strong passwords and account lockout policies to secure your system.

Explore user management by inspecting /etc/passwd, /etc/shadow, and group files, examine password hashes and salt, configure test accounts, set passwords and shells, and assign supplementary groups to control access.

Explore Linux permissions and ownership, learn how to view and modify file access with owner, group, and world roles, using ls, chmod, and chown.

Explore pam configuration with password quality and fail lock settings, adjust min length and complexity via credits or explicit rules, and observe fail lock and reset mechanics in pam_unix.

Manage Linux firewall security with firewalld by configuring zones and zone-based rules and services across networks, and learn why host-based firewalls enhance security even when a dedicated firewall sits outside.

Configure firewall zones with firewall-cmd, assign interfaces to work, public, or home zones, and set rules with the permanent option to persist across reboots, noting the default zone is public.

Lock down grub by creating a SHA-512 hashed password with PBKDF2, set a super user, and write the grub configuration to /boot to prevent attackers from altering boot parameters.

Learn how rsyslog collects and routes Linux logs using facilities and priorities, directing output to files or remote systems, with reliable, auditable logs for incident investigations.

Learn how remote logging centralizes enterprise-wide log collection using rsyslog and tools like Logstash, enabling secure, auditable analysis across the network while configuring queuing and least-privilege operation.

Learn how auditd monitors linux system activity with file watches and system-call rules, tracks file changes and permissions, and uses preconfigured audit rules for centralized log analysis.

Learn how auditd reporting turns raw logs into actionable insights by using reports and searches to summarize events, such as user logins and SE Linux failures.

Use audit2allow to generate SELinux policy modules that permit necessary actions after testing in permissive mode. Load and distribute the module to enable httpd access to /content.