To ensure the quality and safety of Web applications, security testing is a necessity. So, how do you cover all the different threats-SQL injection, cross-site scripting, buffer overflow, and others? James Knowlton explains how Ruby combined with Watir-both freely available-makes a great toolset for testing Web application security. Testing many common security vulnerabilities requires posting data to a Web server via a client, exactly what Watir does. The Ruby side of Watir, a full-function programming language, provides the tools for querying the database, checking audit logs, and other test-related processing. For example, you can use Ruby to generate random data or large datasets to throw at a Web application. James describes common security attacks and demonstrates step-by-step examples of testing these attack types with Ruby and Watir.