Blind XSS

Blind XSS is similar to a stored XSS (which we covered in task 4) in that your payload gets stored on the website for another user to view, but in this instance, you can't see the payload working or be able to test it against yourself first.

• Potential Impact

  Using the correct payload, the attacker's JavaScript could make calls back to an attacker's website, revealing the staff portal URL, the staff member's cookies, and even the contents of the portal page that is being viewed. Now the attacker could potentially hijack the staff member's session and have access to the private portal.

• How to test for Blind XSS

  When testing for Blind XSS vulnerabilities, you need to ensure your payload has a call back (usually an HTTP request). This way, you know if and when your code is being executed.

  A popular tool for Blind XSS attacks is xsshunter (opens in a new tab). Although it's possible to make your own tool in JavaScript, this tool will automatically capture cookies, URLs, page contents and more.

• Example Scenario

  A website has a contact form where you can message a member of staff. The message content doesn't get checked for any malicious code, which allows the attacker to enter anything they wish. These messages then get turned into support tickets which staff view on a private web portal.