This can be exploited to compromise the application, access files of arbitrary locations on the system, obtain session information, etc. Bypassing the application’s input validation can lead to a variety of issues, some of which are enumerated below.

1. Accidentally deleting or modifying data.

2. Accidentally purchasing something you didn’t intend to purchase.

3. Accidentally signing up for something you don’t want to sign up for.

4. Accidentally giving away something you didn’t intend to give away.

5. Hiding or viewing information that you want to view.

6. Registering an email address that has had any data associated with it.

7. Manipulating information.

8. Logging in as another user.

9. Selling items that you don’t have the rights to sell.

10. Selling an item to an unsuspecting buyer that you don’t have the rights to sell the item to.

11. Selling an item to an unsuspecting buyer that you don’t have the rights to sell the item to.

12. Selling an item to an unsuspecting buyer that you don’t have the rights to sell the item to.

13. Selling an item to an unsuspecting buyer that you don’t have the rights to sell the item to.

14. Selling an item to

Checklist for Identifying and Avoiding Cross-Site Scripting Vulnerabilities in Web Applications o Ensure that your application does not perform any sensitive operations in a user-supplied context.

o Ensure that all input is validated to ensure no malicious or unintended data has been supplied.
o Ensure that your code uses the same type of input validation.
o If you are using cookies, make sure they are only being used to identify a unique session by hashing and encrypting the cookie ID.
o Never use a visitor's browser as an identifier for anything other than to log them out if they have already authenticated successfully.
o Always ensure that filters exist on forms before sending requests so that only valid data is submitted to the server.
o Make sure you are operating with knowledge of what your web application actually does and make sure it is secure from all possible vectors of attack.

How the attack works?

The vulnerability is caused by an input validation error. The application incorrectly validates the user’s inputs.

In this case, the application assumes that users can only enter one email address in a given form field at a time. When the user enters multiple emails in separate fields, the application won’t validate them properly, and will accept all of them as valid.

A successful attack begins with an unauthenticated attacker sending a crafted request to the vulnerable system. The vulnerability exists due to a vulnerability in how two parameters are validated when performing email validation. This vulnerability was discovered by David Kohl from Ralph DeGroot who found out that if he sends two emails with different subject lines, he can bypass validation and enter any number of emails without any consequences.

Timeline

Published on: 10/07/2022 19:15:00 UTC
Last modified on: 10/10/2022 02:16:00 UTC

References