Book Image

Practical Linux Security Cookbook - Second Edition

By : Tajinder Kalsi
Book Image

Practical Linux Security Cookbook - Second Edition

By: Tajinder Kalsi

Overview of this book

Over the last few years, system security has gained a lot of momentum and software professionals are focusing heavily on it. Linux is often treated as a highly secure operating system. However, the reality is that Linux has its share of security ?aws, and these security ?aws allow attackers to get into your system and modify or even destroy your important data. But there’s no need to panic, since there are various mechanisms by which these ?aws can be removed, and this book will help you learn about different types of Linux security to create a more secure Linux system. With a step-by-step recipe approach, the book starts by introducing you to various threats to Linux systems. Then, this book will walk you through customizing the Linux kernel and securing local files. Next, you will move on to managing user authentication both locally and remotely and mitigating network attacks. Later, you will learn about application security and kernel vulnerabilities. You will also learn about patching Bash vulnerability, packet filtering, handling incidents, and monitoring system logs. Finally, you will learn about auditing using system services and performing vulnerability scanning on Linux. By the end of this book, you will be able to secure your Linux systems and create a robust environment.
Table of Contents (20 chapters)
Title Page
Copyright and Credits
Contributors
Packt Upsell
Preface
Index

Setting up a Kerberos server with Ubuntu


Kerberos is an authentication protocol for allowing secure authentication over untrusted networks by using secret-key cryptography and trusted third parties.

Getting started

To see Kerberos set up and running, we need three Linux systems (in our example we have used Ubuntu). They should be able to communicate with each other, and they should also have accurate system clocks.

We have set the hostname for each system is as follows:

  • Kerberos system – mykerberos.com
  • SSH Server system – sshserver.com
  • Client system – sshclient.com

After doing this, edit the /etc/hosts file in each system and add the following details:

The IP address and the hostname can be different for your systems. Just make sure that after doing these changes they can still ping with each other.

How to do it...

Now let's see how to do the setup of Kerberos server and the other systems for our example:

  1. The first step is to install the Kerberos server. To do this, we will run the following command...