The Web Application Hacker’s Handbook Discovering and Exploiting Security Flaws

not always sufficient simply to post it as each parameter to each page.

Many application functions need to be followed through several stages

before the submitted data is actually stored. For example, actions like

registering a new user, placing a shopping order, and making a funds

transfer often involve submitting several different requests in a defined

sequence. To avoid missing any vulnerabilities, it is necessary to see each

test case through to completion.

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When probing for reflected XSS, you are interested in every aspect of a

victim’s request that you can control. This includes all parameters to the

request, and also every HTTP header, because these can be controlled

using a crafted Flash object. In the case of stored XSS, you should also

investigate any out-of-band channels through which the application