Book Image

Mastering Linux Security and Hardening - Third Edition

By : Donald A. Tevault
3.7 (7)
Book Image

Mastering Linux Security and Hardening - Third Edition

3.7 (7)
By: Donald A. Tevault

Overview of this book

The third edition of Mastering Linux Security and Hardening is an updated, comprehensive introduction to implementing the latest Linux security measures, using the latest versions of Ubuntu and AlmaLinux. In this new edition, you will learn how to set up a practice lab, create user accounts with appropriate privilege levels, protect sensitive data with permissions settings and encryption, and configure a firewall with the newest firewall technologies. You’ll also explore how to use sudo to set up administrative accounts with only the privileges required to do a specific job, and you’ll get a peek at the new sudo features that have been added over the past couple of years. You’ll also see updated information on how to set up a local certificate authority for both Ubuntu and AlmaLinux, as well as how to automate system auditing. Other important skills that you’ll learn include how to automatically harden systems with OpenSCAP, audit systems with auditd, harden the Linux kernel configuration, protect your systems from malware, and perform vulnerability scans of your systems. As a bonus, you’ll see how to use Security Onion to set up an Intrusion Detection System. By the end of this new edition, you will confidently be able to set up a Linux server that will be secure and harder for malicious actors to compromise.
Table of Contents (22 chapters)
1
Section 1: Setting up a Secure Linux System
9
Section 2: Mastering File and Directory Access Control (DAC)
12
Section 3: Advanced System Hardening Techniques
20
Other Books You May Enjoy
21
Index

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 are created from scratch every time you boot a Linux machine, and then cleared out every time you shut down the machine. Within /proc/, you’ll find two general classes of information:

...