This lab blocks all HTML tags except custom ones.
To solve the lab, perform a cross-site scripting attack that injects a custom tag and automatically alerts
Go to the exploit server and paste the following code, replacing
your-lab-id with your lab ID:
location = 'https://your-lab-id.web-security-academy.net/?search=%3Cxss+id%3Dx+onfocus%3Dalert%28document.cookie%29%20tabindex=1%3E#x';
Click "Store" and "Deliver exploit to victim".
This injection creates a custom tag with the ID
x, which contains an
onfocus event handler that triggers the
alert function. The hash at the end of the URL focuses on this element as soon as the page is loaded, causing the
alert payload to be called.