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

Identifying Entry Points for User Input

The majority of ways in which the application captures user input for server-

side processing should be obvious when reviewing the HTTP requests that are

generated as you walk through the application’s functionality. The key loca-

tions to pay attention to are:

■■

Every URL string up to the query string marker.

■■

Every parameter submitted within the URL query string.

■■

Every parameter submitted within the body of a 

POST

request.

■■

Every cookie.

■■

Every other HTTP header that in rare cases may be processed by the

application, in particular the 

User-Agent

, 

Referer

, 

Accept

, 

Accept-

Language

, and 

Host

headers.