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

N OT E

When an application handles a request containing a structured token,

it may not actually process every component with the token or all of the data

contained within each component. In the previous example, the application

may Base64-decode the token and then process only the “user” and “date”

components. In cases where a token contains a blob of binary data, much of

this data may be padding, and only a small part of it may actually be relevant

to the validation that the server performs on the token. Narrowing down the

subparts of a token that are actually required can often reduce considerably the

amount of apparent entropy and complexity that the token contains.

Chapter 7 

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Attacking Session Management

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HACK STEPS

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