Book Image

Practical Linux Security Cookbook

By : Michael A Lindner, Tajinder Kalsi
Book Image

Practical Linux Security Cookbook

By: Michael A Lindner, Tajinder Kalsi

Overview of this book

With the growing popularity of Linux, more and more administrators have started moving to the system to create networks or servers for any task. This also makes Linux the first choice for any attacker now. Due to the lack of information about security-related attacks, administrators now face issues in dealing with these attackers as quickly as possible. Learning about the different types of Linux security will help create a more secure Linux system. Whether you are new to Linux administration or experienced, this book will provide you with the skills to make systems more secure. With lots of step-by-step recipes, the book starts by introducing you to various threats to Linux systems. You then get to walk through customizing the Linux kernel and securing local files. Next you will move on to manage user authentication locally and remotely and also mitigate network attacks. Finally, you will learn to patch bash vulnerability and monitor system logs for security. With several screenshots in each example, the book will supply a great learning experience and help you create more secure Linux systems.
Table of Contents (17 chapters)
Practical Linux Security Cookbook
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Remote server/host access using SSH


SSH, or Secure Shell, is a protocol which is used to log on to remote systems securely and is the most commonly used method for accessing remote Linux systems.

Getting ready

To see how to use SSH, we need two Ubuntu systems. One will be used as a server and the other as a client.

How to do it…

To use SSH, we can use freely available software called OpenSSH. Once the software is installed, it can be used by the command ssh on the Linux system. We will see how to use this tool in detail:

  1. If the software to use SSH is not already installed, we have to install it on both the server and the client system.

    • The command to install the tool on the server system is:

      	sudo apt-get install openssh-server
      
    • The output obtained will be as follows:

  2. Next, we need to install the client version of the software:

    sudo apt-get install openssh-client
    
    • The output obtained will be as follows:

  3. For the latest versions, the SSH service starts running as soon as the software is installed. If...