the-web-application-hackers-handbook

CHAPTER
21
A Web Application Hacker’s
Methodology
This chapter contains a detailed step-by-step methodology you can follow when
attacking a web application. It covers all the categories of vulnerabilities and
attack techniques described in this book. Following all the steps in this methodology
will not guarantee that you discover all the vulnerabilities within a
given application. However, it will provide you with a good level of assurance
that you have probed all the necessary regions of the application’s attack surface
and have found as many issues as possible given the resources available to you.
Figure 21-1 illustrates the main areas of work that this methodology describes.
We will drill down into this diagram and illustrate the subdivision of tasks that
each area involves. The numbers in the diagrams correspond to the hierarchical
numbered list used in the methodology, so you can easily jump to the actions
involved in a specific area.
The methodology is presented as a sequence of tasks that are organized and
ordered according to the logical interdependencies between them. As far as possible,
these interdependencies are highlighted in the task descriptions. However,
in practice you will frequently need to think imaginatively about the direction
in which your activities should go and allow these to be guided by what you
discover about the application you are attacking. For example:
n Information gathered in one stage may enable you to return to an earlier
stage and formulate more focused attacks. For example, an access control
bug that enables you to obtain a listing of all users may enable you to
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