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

Using System tools – strace


When running any command or program on our Linux machine, we might wonder what the background working of it is. For this, we have a very useful tool in Linux called strace.

It's a command-line tool which can be also used as a diagnostic or debugging tool. Strace monitors the interaction between the processes, and the Linux kernel and is helpful when we would like to debug the execution of any program.

Getting ready

This tool is available for all Linux-based systems by default. Hence, nothing else needs to be configured to start using strace.

How to do it...

Let's see how strace can be used in various ways to trace the execution of any program, from start to end:

  1. To trace the execution of any executable command in Linux, simply run the strace command followed by the executable command. If we use strace for the ls command, we get the following output:
  1. In the preceding screenshot, the output displayed has been truncated. If we check the last few lines of the output, we...