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

User authentication and logging


One of the major aspects of user authentication is monitoring the users of the system. There are various ways to keep track of all the successful and failed login attempts made by a user in Linux.

Getting Started

The Linux system maintains a log of all login attempts by different accounts in the system. These logs are all located at /var/log/.

How to do it...

Linux has many ways to help an administrator to view the logs, both through a graphical and command-line method:

  1. If we want to check the incorrect login attempts for a particular user, such as root, we can do so by using this command:

    lastb root
    
  2. To see the log using the terminal, we use the dmesg command. This command displays the buffer of Linux kernel's message stored in memory, as shown below:

  3. If we wish to filter the above output to only show the log related to a USB device, we can do so by using grep:

  4. Instead of viewing all the logs, if we only wish to view the 10 most recent logs in a particular log file...