In this era of Web 2.0, more organizations are developing rich online applications. These applications are designed for e-commerce business, banking transactions, stock trading, storing medical records, and more. To provide rich user experience, the application interacts with the user and also stores the sensitive personal information of those using the application. From a security perspective, the developers of these applications need to take necessary measures to secure the application and maintain the integrity of the sensitive data.

The major concern when an application relies on user input is that it cannot trust the end user to provide non-malicious data. The user may use a script in place of a username and it is the responsibility of the application to decide the legitimate data input for that parameter. When it fails to sanitize the input, the attacker can exploit this condition and execute a scripting attack.

In this chapter,...