Web Security Testing Cookbook

Foreword

Gary McGraw, July 2008

Web applications suffer more than their share of security attacks. Here’s why. Websites and the applications that exist on them are in some sense the virtual front door of all corporations and organizations. Growth of the Web since 1993 has been astounding, outpacing even the adoption of the television and electricity in terms of speed of widespread adoption.

Web applications are playing a growing and increasingly prominent role in software development. In fact, pundits currently have us entering the era of Web 3.0 (see http://www.informit.com/articles/article.aspx?p=1217101). The problem is that security has frankly not kept pace. At the moment we have enough problems securing Web 1.0 apps that we haven’t even started on Web 2.0, not to mention Web 3.0.

Before I go on, there’s something I need to get off my chest. Web applications are an important and growing kind of software, but they’re not the only kind of software! In fact, considering the number of legacy applications, embedded devices, and other code in the world, my bet is that web applications make up only a small percentage of all things software. So when all of the software security attention of the world is focused solely on web applications, I get worried. There are plenty of other kinds of critical applications out there that don’t live on the Web. That’s why I think of myself as a software security person and not a Web application security person.

In any case, Web application security and software security do share many common problems and pitfalls (not surprising since one is a subset of the other). One common problem is treating security as a feature, or as “stuff.” Security is not “stuff.” Security is a property of a system. That means that no amount of authentication technology, magic crypto fairy dust, or service-oriented architecture (SOA) ws-* security API will automagically solve the security problem. In fact, security has more to do with testing and assurance than anything else.

Enter this book. Boy, do we need a good measure of web application security testing! You see, many “tests” devised by security experts for web app testing are not carried out with any testing rigor. It turns out that testing is its own discipline, with an entire literature behind it. What Paco and Ben bring to the table is deep knowledge of testing clue. That’s a rare combination.

One critical factor about tests that all testers worth their salt understand is that results must be actionable. A bad test result reports something vague like “You have an XSS problem in the bigjavaglob.java file.” How is a developer supposed to fix that? What’s missing is a reasonable explanation of what XSS is (cross-site scripting, of course), where in the bazillion-line file the problem may occur, and what to do to fix it. This book has enough technical information in it for decent testers to report actionable results to actual living developers.

Hopefully the lessons in this book will be adopted not only by security types but also by testing people working on web applications. In fact, Quality Assurance (QA) people will enjoy the fact that this book is aimed squarely at testers, with the notions of regression testing, coverage, and unit testing built right in. In my experience, testing people are much better at testing than security people are. Used properly, this book can transform security people into better testers, and testers into better security people.

Another critical feature of this book is its clear focus on tools and automation. Modern testers use tools, as do modern security people. This book is full of real examples based on real tools, many of which you can download for free on the Net. In fact, this book serves as a guide to proper tool use since many of the open source tools described don’t come with built-in tutorials or how-to guides. I am a fan of hands-on material, and this book is about as hands-on as you can get.

An overly optimistic approach to software development has certainly led to the creation of some mind-boggling stuff, but it has likewise allowed us to paint ourselves into the corner from a security perspective. Simply put, we neglected to think about what would happen to our software if it were intentionally and maliciously attacked. The attackers are at the gates, probing our web applications every day.

Software security is the practice of building software to be secure and function properly under malicious attack. This book is about one of software security’s most important practices—security testing.