I still remember the first time I found a high-impact vulnerability. I had already located a few low-impact bugs in the application I was testing, including a CSRF, an IDOR, and a few information leaks. Eventually, I managed to chain these into a full takeover of any account on the website: I could have logged in as anyone, read anyone’s data, and altered it however I wanted. For an instant, I felt like I had superpowers.

I reported the issue to the company, which promptly fixed the vulnerability. Hackers are probably the closest thing to superheroes I’ve encountered in the real world. They overcome limitations with their skills to make software programs do much more than they were designed for, which is what I love about hacking web applications: it’s all about thinking creatively, challenging yourself, and doing more than what seems possible.

Also like superheroes, ethical hackers help keep society safe. Thousands of data breaches happen every year in the United States alone. By understanding vulnerabilities and how they happen, you can use your knowledge for good to help prevent malicious attacks, protect applications and users, and make the internet a safer place.

Not too long ago, hacking and experimenting with web applications were illegal. But now, thanks to bug bounty programs, you can hack legally; companies set up bug bounty programs to reward security researchers for finding vulnerabilities in their applications. Bug Bounty Bootcamp teaches you how to hack web applications and how to do it legally by participating in these programs. You’ll learn how to navigate bug bounty programs, perform reconnaissance on a target, and identify and exploit vulnerabilities.

Who This Book Is For

This book will help anyone learn web hacking and bug bounty hunting from scratch. You might be a student looking to get into web security, a web developer who wants to understand the security of a website, or an experienced hacker who wants to understand how to attack web applications. If you are curious about web hacking and web security, this book is for you.

No technical background is needed to understand and master the material of this book. However, you will find it useful to understand basic programming.

Although this book was written with beginners in mind, advanced hackers may also find it to be a useful reference. In particular, I discuss advanced exploitation techniques and useful tips and tricks I’ve learned along the way.

What Is In This Book

Bug Bounty Bootcamp covers everything you need to start hacking web applications and participating in bug bounty programs. This book is broken into four parts: The Industry, Getting Started, Web Vulnerabilities, and Expert Techniques.

Part I: The Industry

1. The first part of the book focuses on the bug bounty industry. Chapter 1: Picking a Bug Bounty Program explains the various types of bug bounty programs and how to choose one that suits your interests and experience level. Chapter 2: Sustaining Your Success teaches you the nontechnical skills you need to succeed in the bug bounty industry, like writing a good report, building professional relationships, and dealing with conflict and frustration.

Part II: Getting Started

1. The second part of the book prepares you for web hacking and introduces you to the basic technologies and tools you’ll need to successfully hunt for bugs.

   Chapter 3: How the Internet Works explains the basics of internet technologies. It also introduces the internet security mechanisms you will encounter, such as session management, token-based authentication, and the same-origin policy.

   Chapter 4: Environmental Setup and Traffic Interception shows you how to set up your hacking environment, configure Burp Suite, and effectively utilize Burp Suite’s various modules to intercept traffic and hunt for bugs.

   Chapter 5: Web Hacking Reconnaissance details the recon strategies you can take to gather information about a target. It also includes an introduction to bash scripting and shows you how to create an automated recon tool from scratch.

Part III: Web Vulnerabilities

1. Then we start hacking! This part, the core of the book, dives into the details of specific vulnerabilities. Each chapter is dedicated to a vulnerability and explains what causes that vulnerability, how to prevent it, and how to find, exploit, and escalate it for maximum impact.

   Chapters 6 through 18 discuss common vulnerabilities you are likely to encounter in real-life applications, including cross-site scripting (XSS), open redirects, clickjacking, cross-site request forgery (CSRF), insecure direct object references (IDOR), SQL injection, race conditions, server-side request forgery (SSRF), insecure deserialization, XML external entity vulnerabilities (XXE), template injection, application logic errors and broken access control, and remote code execution (RCE).

   Chapter 19: Same-Origin Policy Vulnerabilities dives into a fundamental defense of the modern internet: the same-origin policy. You’ll learn about the mistakes developers make when building applications to work around the same-origin policy and how hackers can exploit these mistakes.

   Chapter 20: Single-Sign-On Security Issues discusses the most common ways applications implement single-sign-on features, the potential weaknesses of each method, and how you can exploit these weaknesses.

   Finally, Chapter 21: Information Disclosure discusses several ways of extracting sensitive information from a web application.

Part IV: Expert Techniques

1. The final part of the book introduces in-depth techniques for the experienced hacker. This section will help you advance your skills once you understand the basics covered in Part III.

   Chapter 22: Conducting Code Reviews teaches you how to identify vulnerabilities in source code. You will also get the chance to practice reviewing a few pieces of code.

   Chapter 23: Hacking Android Apps teaches you how to set up your mobile hacking environment and find vulnerabilities in Android applications.

   Chapter 24: API Hacking discusses application programming interfaces (APIs), an essential part of many modern applications. I discuss types of APIs and how to hunt for vulnerabilities that manifest in them.

   Chapter 25: Automatic Vulnerability Discovery Using Fuzzers wraps up the book by showing you how to automatically hunt for vulnerabilities by using a method called fuzzing. You’ll practice fuzzing a web application with an open source fuzzer.

Happy Hacking!

Bug Bounty Bootcamp is not simply a book about bug bounties. It is a manual for aspiring hackers, penetration testers, and people who are curious about how security works on the internet. In the following chapters, you will learn how attackers exploit common programming mistakes to achieve malicious goals and how you can help companies by ethically reporting these vulnerabilities to their bug bounty programs. Remember to wield this power responsibly! The information in this book should be used strictly for legal purposes. Attack only systems you have permission to hack and always exercise caution when doing so. Happy hacking!