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3h 21m

In this section, you’ll take a deep dive into Linux security. You’ll build your knowledge and skills through a comprehensive overview of the key areas that you need to know to secure Linux systems.

You’ll begin with Linux security in general before moving on to physical security and the countermeasures you can employ to protect your hardware. From there, you’ll explore authentication systems and the various account types on a Linux system, and how to secure each one. You'll also learn how to enforce strong passwords and manage account and password expirations.

In the networking section, you'll learn how to secure network services that run on Linux systems. You'll also learn how the local firewall works in Linux and how to configure it. You’ll learn about file system security and how permissions work in detail, including special modes, file attributes, and ACLs. You'll also discover what rootkits are, how to detect them, and how to remove them.

You’ll also find several security resources you can use to continue your security education and stay on top of the latest security issues for Linux distributions.

There are several knowledge checks as you go through these resources. These will help you identify any areas that you might need or want to review. At the end you’ll find a final exam, where you can test yourself on what you’ve learnt.

Learning Objectives

  • Get a general view of Linux security including roles, network services, encryption, accounts, and multifactor authentication
  • Learn specific strategies for mitigating physical security risks and protecting your Linux systems against the most common physical attacks
  • Learn about data encryption and how to implement it on new Linux systems, as well as those that are already in service
  • Understand the different types of accounts you'll find on a Linux system and the special precautions you need to take with each account type
  • Learn how to enforce good password security practices on your Linux systems
  • Learn about multi-factor authentication and how it can be implemented in Linux
  • Learn techniques and strategies to secure network services
  • Learn how to secure your files and directories on Linux through permissions, data sharing, special modes, file attributes, ACLs, and rootkits

In this section of the course, you learned that even though Linux is a relatively secure operating system that doesn't mean you can let your guard down. End users and system administrators alike play an important role in security. Some of those people may not have the proper training. Some are not security focused and everybody makes mistakes from time to time. Sometimes those mistakes can have security implications. We also talked about how security is an ongoing process. Once systems are put into service, they change through use. Accounts need to be created or deleted, logs need to be monitored, et cetera. Security is a consideration for the entire lifespan of a system. You also learned about some of the security features of Linux, including that it's open source. It's not as easy or popular of a target than some other operating systems are currently. You also learned about the security advantages of using packages provided by popular Linux distributions. We even talked about the advantages of Linux being a multi-user operating system. Finally, we talked about several security principles and guidelines. Some of these included the principle of least privilege using encryption over the network as well as on disc, how to handle shared accounts and how using multi-factor authentication mechanisms enhance security. You learned about the built-in firewall capabilities of Linux. Finally, we talked about the importance of reviewing, monitoring, and securing logs on your systems.

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