Cross Site Request Forgery ( CSRF ) Example tagged:

Cross Site Request Forgery ( CSRF ) Example

Posted by in Articles, Hacks

In this post I’ll show your cross site request forgery ( CSRF ) example . I’ve created web application that simulate money transferring app and it’s vulnerable to CSRF attack , so you can try example on live website .

What is CSRF ?

Cross Site Request Forgery works by exploiting the trust that a site has for the user. Site tasks are usually linked to specific urls
(Example: http://hackspc.com/sellpage?money=1000&count=145689782562) allowing specific actions to be performed when requested. If a user is logged into the site and an attacker tricks their browser into making a request to one of these task urls. Typically an attacker will embed malicious HTML or
JavaScript code into an email or website to request a specific ‘task url’ which executes without the users knowledge.

CSRF Example

Let’s say that user with username „ hackspc.com“ visits Web application for money transferring and log in with username: hackspc.com and password: 12345 . You can find that web application on http://websecurityexamples.com/CSRF/

In our web application user has option to send money to other accounts .

After logging in, you will see at the bottom bank status of all users

If you log in with username hackspc.com and type into field Amount: 100 and into field Send money to: 124578326598 . You will transfer amount of 100 to bank account 124578326598 .

Below is image that shows bank status after transferring amount of 100 from user hackspc.com to bank account 124578326598 .

Pay attention to the field “Amount” . You’ll see that the amount of user with username “hackspc.com ” decreased by 100, while the number of user with username “Hacker” increased by 100

It is the simplest princip of how bank application works .

Let’s say that user with username Hacker published on forum image with a malicious IMG tag . SRC attribut from malicious image is GET request that execute command for transferring of money.
So , how CSRF attack works ? Let’s say that user hackspc.com , while he is logged in web application for transferring of money visits forum called „hackers_xxxxx“ .
Web client from user hackspc.com will load image with malicious code and execute it. Web client will be fooled , because user hackspc.com is logged while visiting forum „hackers_xxxxx“ and it will send GET request that transferring amount of 1000 from user hackspc.com to bank account 124578326598 . :

http://websecurityexamples.com/CSRF/transaction2.php?Amount=100&Send_money_to=124578326598

to web application for money transferring.

malicious image :

Normal IMG tag has SRC attribut that points to location where image is placed . It looks as show below:

You can download complete web application for money transferring that is vulnerable to CSRF attack on this LINK

If you want to learn more about web security visit my previous article
Cross Site Scripting Example
How To Protect Your Website Against SQL Injection