BurpSuite Lab: Excessive trust in client-side controls | WalkThrough

Introduction

Business logic vulnerabilities are flaws in the design and implementation of an application that allow an attacker to elicit unintended behavior. This potentially enables attackers to manipulate legitimate functionality to achieve a malicious goal. These flaws are generally the result of failing to anticipate unusual application states that may occur and, consequently, failing to handle them safely. Here we are going to use this vulnerability to purchase a $1337 [Fake]jacket in $0.01 .

Target

This lab doesn’t adequately validate user input. You can exploit a logic flaw in its purchasing workflow to buy items for an unintended price. To solve the lab, buy a “Lightweight l33t leather jacket”.

You can log in to your own account using the following credentials: wiener:peter

Detection

Login with the credential that is given to us.

We have only 100$ and that jacket cost 1337$ . So, we need to trick the server somehow in order to purchase the jacket.

Add that jacket to the cart.

There is a price field in the requests . we can modify it to lower the jackets price and can purchase it.

Exploitation

Change the price field in requests to 1$ .

And we successfully bought that jacket in only 0.01$ .