In the first recipe of this chapter, we learned that CSRF is an important part of webform security. We will now talk about this in detail. CSRF basically means that someone can hack into the request that carries a cookie and use this to trigger a destructive action. We won't be discussing CSRF in detail here, since ample resources are available on the internet to learn about this. We will talk about how WTForms will help us in preventing CSRF. Flask does not provide any security against CSRF by default, as this has to be handled at the form-validation level, which is not provided by Flask. However, in this recipe, we will see how this is done for us by means of the Flask-WTF extension.
More information about CSRF can be found at https://www.owasp.org/index.php/Cross-Site_Request_Forgery_(CSRF).
