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 – whowatch


While keeping a watch on the network, the administrator would also like to keep a watch on the users who are currently logged on to the system and also what each user is doing on the machine.

Whowatch is the perfect tool for such tasks. It uses a simple text-based interface which is easy to use and can display information about the user's username, processes, and so on, and also the type of connection , such as SSH and telnet.

Getting ready

Since Whowatch doesn't come as a pre-installed package in Linux, we have to install it to use it. The command to install whowatch is as follows:

apt-get install whowatch

How to do it...

For utilizing the Whowatch tool to its maximum benefit, we have to understand the details of the tool properly:

  1. To start using the tool, just enter the whowatch command, and a screen will appear as follows:

The preceding screen lists all the user accounts that are logged in.

  1. From this list, we can select any user account, and when we press Enter, we...