Cybersecurity is one of the most rapidly growing fields in information technology. Every day, numerous attacks are executed against various entities, from individuals to large enterprises and even governments. Due to these threats in the digital world, new professions are being created within organizations for people who can protect assets. This book aims to give you the knowledge and techniques that an aspiring penetration tester needs in order to enter the field of cybersecurity. A penetration tester is a professional who has the skills of a hacker; they are hired by an organization to perform simulations of real-world attacks on their network infrastructure with the objective of discovering security vulnerabilities before a real attack occurs. The penetration tester does this task with written legal permission from the target organization. To become a highly skilled hacker, it's vital to have a strong understanding of computers, networking, and programming, as well as how they work together. Most importantly, however, you need creativity. Creative thinking allows a person to think outside the box and go beyond the intended uses of technologies and find exciting new ways to implement them, doing things with them that were never intended by their developers. In some ways, hackers are artists.

Throughout this book, we will be using one of the most popular operating systems for penetration testing, Kali Linux. The Kali Linux operating system has hundreds of tools and utilities designed to assist you during a vulnerability assessment, penetration test, or even a digital forensics investigation in the field of cybersecurity. We will use Kali Linux to take you through various topics using a student-centric approach, filled with a lot of hands-on exercises starting from beginner level to intermediate to more advanced topics and techniques.

In this chapter, you will become acquainted with what hackers are and how they can be classified based on motivations and actions. You'll learn important terminology and look at methods and approaches that will help you throughout this book and set you on your path to becoming a penetration tester. You'll be introduced to the workflow of a hack as well.

In this chapter, we will look at the following topics:

• Who is a hacker?
• Key terminology
• Penetration testing phases
• Penetration testing methodologies
• Penetration testing approaches
• Types of penetration testing
• Hacking phases