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

Applying patches in Linux


Whenever a security vulnerability is found in any software, a security patch is released for the software to fix the bug. Normally, we use the Update Manager that's built into Linux to apply the security updates. However, for software that we install by compiling the source code, Update Manager may not be helpful.

For such situations, we can apply the patch file to the original software's source code and then recompile the software.

Getting ready

Since we will use the built-in commands of Linux to create and apply a patch, nothing needs to be done before starting the following steps. We will be creating a sample program in C for understanding the process of creating a patch file.

How to do it...

In this section, we will see how to create a patch for a program, using the diff command, and then apply the patch using the patch command:

  1. Our first step will be to create a simple C program called example.c to print This is an example, as follows:
  1. Now, we will create a copy of...