Mastering Linux Security and Hardening, Third Edition

Hardening Linux Without Guesswork 🔐

Linux systems are powerful, but power does not equal safety. Default configurations, inherited accounts, weak password policies, and open services can leave a server exposed long before anyone notices. Mastering Linux Security and Hardening, Third Edition approaches that reality as a working administrator’s problem: what to lock down, why it matters, and how to test each change without breaking the systems you rely on.

What the Third Edition Covers

Donald A. Tevault opens with the threat landscape and the practical differences between physical, virtual, and cloud setups. From there, the book builds a layered defense through administrative and normal user accounts, covering sudo delegation, root shell risks, home directory permissions, password quality, account expiration, and brute-force protections with PAM modules such as pam_tally2 and pam_faillock. Later material moves into firewall fundamentals and the ongoing discipline of keeping Linux hosts updated and auditable.

• Admin account control: sudo policies, delegated privileges, and restrictions that reduce root exposure.
• User account hardening: encrypted home directories, password complexity, expiry rules, and compromised-password checks.
• Brute-force resistance: configuring PAM modules across CentOS, AlmaLinux, and Ubuntu systems.
• Firewall foundations: understanding Linux firewall concepts before writing rules for real services.

Hands-On Labs and Real Commands ⚙️

The book does not stop at concepts. Chapters include hands-on labs and configuration examples, with instructions for VirtualBox, Cygwin, and built-in Windows SSH clients so readers can build a safe practice environment. The third edition reflects newer platforms, including AlmaLinux 8/9 and Ubuntu 20.04/22.04, alongside older Red Hat and CentOS systems that remain in production.

Who Will Get the Most From It 💻

This edition suits system administrators, DevOps engineers, security analysts, and advanced Linux users who need defensive skills rather than a first introduction to the command line. It is also useful for professionals preparing for security-focused responsibilities, because the material connects account policy, access control, and network defense into a coherent hardening workflow.

About the Author

Donald A. Tevault holds Linux Professional Institute Level 3 Security and GIAC Incident Handler certifications. He is a professional Linux trainer and has worked as a Linux security researcher for an IoT security company. That teaching background shows in the book’s step-by-step explanations and lab-driven structure.

Build a Stronger Linux Defense 🛡️

If you manage Linux systems and want a clearer path from default settings to defensible configuration, this third edition offers a grounded, up-to-date reference. Digital Delights delivers the ebook for convenient access, so you can keep the guidance close while you work through your own hardening checklist.