I have implemented in my app the mitigation to CSRF attacks following the informations that I have read on some blog post around the internet. In particular these post have
The Solution i found is not for ASPX but for Razor, but quite comperable issue.
I resolved it by adding the AntiForgery to the request. The HTML Helper does not create a HTML id with the call
@Html.AntiForgeryToken()
In order to add the token to the postrequest i just added the AntiForgery id to the hidden field with jquery:
$("input[name*='__RequestVerificationToken']").attr('id', '__AjaxAntiForgeryForm');
This caused the controller to accept the request with the [ValidateAntiForgeryToken] attribute