Book Image

Mastering Linux Security and Hardening - Second Edition

By : Donald A. Tevault
Book Image

Mastering Linux Security and Hardening - Second Edition

By: Donald A. Tevault

Overview of this book

From creating networks and servers to automating the entire working environment, Linux has been extremely popular with system administrators for the last couple of decades. However, security has always been a major concern. With limited resources available in the Linux security domain, this book will be an invaluable guide in helping you get your Linux systems properly secured. Complete with in-depth explanations of essential concepts, practical examples, and self-assessment questions, this book begins by helping you set up a practice lab environment and takes you through the core functionalities of securing Linux. You'll practice various Linux hardening techniques and advance to setting up a locked-down Linux server. As you progress, you will also learn how to create user accounts with appropriate privilege levels, protect sensitive data by setting permissions and encryption, and configure a firewall. The book will help you set up mandatory access control, system auditing, security profiles, and kernel hardening, and finally cover best practices and troubleshooting techniques to secure your Linux environment efficiently. By the end of this Linux security book, you will be able to confidently set up a Linux server that will be much harder for malicious actors to compromise.
Table of Contents (20 chapters)
1
Section 1: Setting up a Secure Linux System
8
Section 2: Mastering File and Directory Access Control (DAC)
11
Section 3: Advanced System Hardening Techniques

Understanding the /proc filesystem

If you cd into the /proc directory of any Linux distro and take a look around, you'll be excused for thinking that there's nothing special about it. You'll see files and directories, so it looks like it could just be another directory. In reality, though, it's very special. It's one of several different pseudo-filesystems on the Linux system. (The definition of the word pseudo is fake, so you can also think of it as a fake filesystem.)

If you were to pull the primary operating system drive out of a Linux machine and mount it as the secondary drive on another machine, you'll see a /proc directory on that drive, but you won't see anything in it. That's because the contents of the /proc directory is created from scratch every time you boot a Linux machine, and then it's cleared out every time you shut...