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

Kernel testing and debugging


An important part of any open or closed software development cycle is testing and debugging. And the same applies to the Linux kernel. The end goal of testing and debugging is to ensure that the kernel is working in the same way as earlier, even after installing a new kernel source code.

Configuring console for debugging using netconsole

One of the biggest issues with the Linux kernel is kernel panic. It is similar to the Blue Screen of Death for Microsoft Windows operating systems. If the kernel panics, it will dump a lot of information on the screen and just stay there. It is very difficult to trace a kernel panic if the system is rebooted as no logs are created for it. To solve this issue, we can use Netconsole. It is a kernel module that helps by logging kernel printk messages over UDP. This is helpful with debugging problems when logging on disk fails.

Getting ready

Before starting with the configuration of Netconsole, you need to know the MAC address of the...