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

Configuring other miscellaneous security settings

Our SSH configuration is a lot more secure than it used to be, but we can still make it better. Here are a few little tricks that you might not have seen elsewhere.

Disabling X11 forwarding

When you SSH into a server in the normal manner, as we've been doing, you can only run text-mode programs. If you try to remotely run any GUI-based program, such as Firefox, you'll get an error message. But, when you open the sshd_config file of pretty much any Linux distribution, you'll see this line:

X11Forwarding yes

This means that with the right option switch, you can remotely run GUI-based programs. Assuming that you're logging into a machine that has a graphical...