Book Image

The Web Application Hacker's Handbook

By : Dafydd Stuttard, Marcus Pinto
Book Image

The Web Application Hacker's Handbook

By: Dafydd Stuttard, Marcus Pinto

Overview of this book

Web applications are the front door to most organizations, exposing them to attacks that may disclose personal information, execute fraudulent transactions, or compromise ordinary users. This practical book has been completely updated and revised to discuss the latest step-by-step techniques for attacking and defending the range of ever-evolving web applications. Youíll explore the various new technologies employed in web applications that have appeared since the first edition and review the new attack techniques that have been developed, particularly in relation to the client side. The book starts with the current state of web application security and the trends that indicate how it is likely to evolve soon. Youíll examine the core security problem affecting web applications and the defence mechanisms that applications implement to address this problem, and youíll also explore the key technologies used in todayís web application. Next, youíll carry out tasks for breaking into web applications and for executing a comprehensive attack. As you progress, youíll learn to find vulnerabilities in an application's source code and review the tools that can help when you hack web applications. Youíll also study a detailed methodology for performing a comprehensive and deep attack against a specific target. By the end of this book, youíll be able to discover security flaws in web applications and how to deal with them.
Table of Contents (32 chapters)
Free Chapter
About the Authors
About the Technical Editor
MDSec: The Authors’ Company
End User License Agreement

Preventing XSS Attacks

Despite the various manifestations of XSS, and the different possibilities for exploitation, preventing the vulnerability itself is in fact conceptually straightforward. What makes it problematic in practice is the difficulty of identifying every instance in which user-controllable data is handled in a potentially dangerous way. Any given page of an application may process and display dozens of items of user data. In addition to the core functionality, vulnerabilities may arise in error messages and other locations. It is hardly surprising, therefore, that XSS flaws are so hugely prevalent, even in the most security-critical applications.

Different types of defense are applicable to reflected and stored XSS on the one hand, and to DOM-based XSS on the other, because of their different root causes.

Preventing Reflected and Stored XSS

The root cause of both reflected and stored XSS is that user-controllable data is copied into application responses without adequate...