The web Application Hacker's Handbook

http://wormholetravel.net/darkside.html

This book is a practical guide to discovering and exploiting security flaws in web applications. By “web applications” we mean those that are accessed using a web browser to communicate with a web server. We examine a wide variety of different technologies, such as databases, fi le systems, and web services, but only in the context in which these are employed by web applications. If you want to learn how to run port scans, attack fi rewalls, or break into servers in other ways, we suggest you look elsewhere. But if you want to know how to hack into a web application, steal sensitive data, and perform unauthorized actions, this is the book for you. There is enough that is interesting and fun to say on that subject without straying into any other territory.

The focus of this book is highly practical. Although we include suffi cient background and theory for you to understand the vulnerabilities that web applications contain, our primary concern is the tasks and techniques that you need to master to break into them. Throughout the book, we spell out the specifi c steps you need to follow to detect each type of vulnerability, and how to exploit it to perform unauthorized actions. We also include a wealth of real-world examples, derived from the authors’ many years of experience, illustrating how different kinds of security fl aws manifest themselves in today’s web applications.

Security awareness is usually a double-edged sword. Just as application developers can benefi t from understanding the methods attackers use, hackers can gain from knowing how applications can effectively defend themselves. In addition to describing security vulnerabilities and attack techniques, we describe in detail the countermeasures that applications can take to thwart anattacker. If you perform penetration tests of web applications, this will enable you to provide high-quality remediation advice to the owners of the applications you compromise.

This book’s primary audience is anyone who has a personal or professional interest in attacking web applications. It is also aimed at anyone responsible for developing and administering web applications. Knowing how your enemies operate will help you defend against them. We assume that you are familiar with core security concepts such as logins and access controls and that you have a basic grasp of core web technologies such as browsers, web servers, and HTTP. However, any gaps in your current knowledge of these areas will be easy to remedy, through either the explanations contained in this book or references elsewhere.

In the course of illustrating many categories of security fl aws, we provide code extracts showing how applications can be vulnerable. These examples are simple enough that you can understand them without any prior knowledge of the language in question. But they are most useful if you have some basic experience with reading or writing code.