Linux Security Foundations: A Practical Guide to System Processes, Permissions, and Protection

Whether you're a student stepping into the world of cybersecurity or a self-taught learner eager to build real-world skills, this book is your gateway to understanding and mastering Linux from both offensive and defensive perspectives. Designed for readers with a basic familiarity with Linux, it dives deep into the practical techniques that form the backbone of system security.

Through more than 100 hands-on exercises, you'll explore how attackers exploit Linux systems—and how defenders can harden them. Learn to navigate Bash with precision, manage users and authentication, crack password hashes, and uncover hidden processes. You'll gain insight into Systemd’s role in service management and persistence, and develop the skills to configure powerful security frameworks like SELinux and AppArmor.

This book doesn’t just teach theory—it builds capability. You’ll learn how Linux handles file permissions and access control, how software is installed and verified, and how to think like both an attacker and a defender. Each chapter is packed with actionable knowledge that prepares you for real-world scenarios and professional challenges.

What You’ll Learn:

• Create and manage users and authentication systems
• Crack password hashes and understand PAM
• Control processes and Systemd services
• Configure file permissions, ACLs, SELinux, and AppArmor
• Build a strong foundation in Linux security through practical exercises

Mike O’Leary is a professor at Towson University and was the founding director of the School of Emerging Technologies. He developed and teaches hands-on capstone courses in computer security for both undergraduate and graduate students. He coached the Towson University Cyber Defense team to the finals of the National Collegiate Cyber Defense Competition in 2010, 2012, and 2014.