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

Checking kernel parameters using Lynis


Any operating system is as strong as its weakest link. In the case of Linux, any weakness in its kernel would imply a total compromise of the system. Hence it is necessary to check the security configuration of the Linux kernel.

In this topic, we will see how to use Lynis to check for kernel parameters automatically. Lynis has several predefined key pairs to look for in kernel configuration and accordingly provide advice.

Getting ready

To view or edit any security related parameter of Linux kernel, there is the /etc/sysctl.conf file. All the parameters are stored in this file and this is read during boot time. If you wish to see the available kernel parameters in this file, you can do so by running the command:sysctl -a. This command will display an extensive list of configuration settings. The kernel security parameters are also in this list. Lynis helps check the kernel security parameters in this file automatically, thus avoiding the hassle of checking...