Solution Of XSS Game: Level 1 Hello, world of XSS

Hi, Everyone.

It seems that you guys are now working on the XSS game challenge by Google. This post has a solution to level 1 Hello, world of XS.

Description as per the Game :

This level demonstrates a common cause of cross-site scripting where user input is directly included in the page without proper escaping.

Interact with the vulnerable application window below and find a way to make it execute JavaScript of your choosing. You can take actions inside the vulnerable window or directly edit its URL bar.

Mission Objective of the Game :

Inject a script to pop up a JavaScript alert() in the frame below.

Once you show the alert you will be able to advance to the next level. 

Solution To the Game :

The solution is pretty easy, there are no any kind of filtering done to texts we input. So, a simple query <script>alert(9)</script> will pop-up a alert with 9 and the level is done.