5d930ec235
* Solutions added * Bugfixes * Introduction added (including how to start with webgoat and useful tools) * New lesson: Password strength * New lessons: Multi Level Login * Not yet working new lesson: Session fixation (inital release) git-svn-id: http://webgoat.googlecode.com/svn/trunk/webgoat@301 4033779f-a91e-0410-96ef-6bf7bf53c507
63 lines
2.5 KiB
HTML
63 lines
2.5 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
|
<html>
|
|
<head>
|
|
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
|
|
<title>Insecure Client Storage</title>
|
|
<link rel="stylesheet" type="text/css"
|
|
href="/WebGoat/lesson_solutions/formate.css">
|
|
</head>
|
|
<body>
|
|
<p><b>Lesson Plan Title:</b> Insecure Client Storage</p>
|
|
|
|
<p><b>Concept / Topic To Teach:</b><br />
|
|
It is always a good practice to validate all input
|
|
on the server side. Leaving the mechanism for validation
|
|
on the client side leaves it vulnerable to reverse engineering.
|
|
Remember, anything on the client side should not be considered a secret.</p>
|
|
|
|
|
|
|
|
<p><b>General Goal(s):</b><br />
|
|
For this exercise, your mission is to discover a coupon
|
|
code to receive an unintended discount. Then, exploit the use
|
|
of client side validation to submit an order with a cost of zero. </p>
|
|
|
|
<p><b>Solution:</b><br />
|
|
For the solution you need a plugin for your browser, which is capable of debugging
|
|
Javascript. For IE you can use IEWatch. This solution is written for Firebug
|
|
which is a plugin for Firefox.
|
|
</p>
|
|
|
|
<h2>Stage 1</h2>
|
|
<p>
|
|
First we want to try to get a coupon code to get something cheaper. Open
|
|
Firebug and click on the Script Tab. Make sure you choose clientSideValidation.js
|
|
on the dropdown list. Toggle a breakpoint on the line:<br/>
|
|
<code>decrypted = decrypt(coupons[i]);</code></p>
|
|
Now enter a character in the coupon code field. The Javascript gets executed
|
|
but stops at the breakpoint. On the right side you see the parameters
|
|
and there values. Now use the step over symbol or F10. Now you can read
|
|
the clear text of decrypted:
|
|
<center>
|
|
<img src="/WebGoat/lesson_solutions/ClientSideValidation_files/ClientSideValidation_stage1.png" width=450px alt="Stage 1" />
|
|
<b>Figure 1 Firebug in action</b>
|
|
</center>
|
|
<p>
|
|
Now that you know the coupon name enter it in the coupon field, purchase something
|
|
and you are done.
|
|
</p>
|
|
|
|
<h2>Stage 2</h2>
|
|
<p>
|
|
You can not edit the Prices in the Shopping Cart. The reason is that the readonly
|
|
attribute is set for this field.
|
|
</p>
|
|
<p>To get rid of this attribute open Firebug. Make sure this time you use
|
|
the HTML View. You can directly in
|
|
Firebug search for readonly and elemenate this attribute.The field for the total is
|
|
called GRANDTOT. After having deleted the readonly attribute from GRANDTOT
|
|
it is possible to change the price directly in the browser. Select any products
|
|
you like, change the total field to 0 and hit the purchase button.</p>
|
|
|
|
</body>
|
|
</html> |