jQuery Ajax calls and the Html.AntiForgeryToken()

Question

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

Answer 1

first use @Html.AntiForgeryToken() in html

 $.ajax({
        url: "@Url.Action("SomeMethod", "SomeController")",
        type: 'POST',
        data: JSON.stringify(jsonObject),
        contentType: 'application/json; charset=utf-8',
        dataType: 'json',
        async: false,
        beforeSend: function (request) {
            request.setRequestHeader("RequestVerificationToken", $("[name='__RequestVerificationToken']").val());
        },
        success: function (msg) {
            alert(msg);
        }

Answer 2

I know there are a lot of other answers, but this article is nice and concise and forces you to check all of your HttpPosts, not just some of them:

http://richiban.wordpress.com/2013/02/06/validating-net-mvc-4-anti-forgery-tokens-in-ajax-requests/

It uses HTTP headers instead of trying to modify the form collection.

Server

//make sure to add this to your global action filters
[AttributeUsage(AttributeTargets.Class)]
public class ValidateAntiForgeryTokenOnAllPosts : AuthorizeAttribute
{
    public override void OnAuthorization( AuthorizationContext filterContext )
    {
        var request = filterContext.HttpContext.Request;

        //  Only validate POSTs
        if (request.HttpMethod == WebRequestMethods.Http.Post)
        {
            //  Ajax POSTs and normal form posts have to be treated differently when it comes
            //  to validating the AntiForgeryToken
            if (request.IsAjaxRequest())
            {
                var antiForgeryCookie = request.Cookies[AntiForgeryConfig.CookieName];

                var cookieValue = antiForgeryCookie != null
                    ? antiForgeryCookie.Value 
                    : null;

                AntiForgery.Validate(cookieValue, request.Headers["__RequestVerificationToken"]);
            }
            else
            {
                new ValidateAntiForgeryTokenAttribute()
                    .OnAuthorization(filterContext);
            }
        }
    }
}

Client

var token = $('[name=__RequestVerificationToken]').val();
var headers = {};
headers["__RequestVerificationToken"] = token;

$.ajax({
    type: 'POST',
    url: '/Home/Ajax',
    cache: false,
    headers: headers,
    contentType: 'application/json; charset=utf-8',
    data: { title: "This is my title", contents: "These are my contents" },
    success: function () {
        ...
    },
    error: function () {
        ...
    }
});

Answer 3

You can do this also:

$("a.markAsDone").click(function (event) {
    event.preventDefault();

    $.ajax({
        type: "post",
        dataType: "html",
        url: $(this).attr("rel"),
        data: $('<form>@Html.AntiForgeryToken()</form>').serialize(),
        success: function (response) {
        // ....
        }
    });
});

This is using Razor, but if you're using WebForms syntax you can just as well use <%= %> tags

Answer 4

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

Answer 5

found this very clever idea from https://gist.github.com/scottrippey/3428114 for every $.ajax calls it modifies the request and add the token.

// Setup CSRF safety for AJAX:
$.ajaxPrefilter(function(options, originalOptions, jqXHR) {
    if (options.type.toUpperCase() === "POST") {
        // We need to add the verificationToken to all POSTs
        var token = $("input[name^=__RequestVerificationToken]").first();
        if (!token.length) return;

        var tokenName = token.attr("name");

        // If the data is JSON, then we need to put the token in the QueryString:
        if (options.contentType.indexOf('application/json') === 0) {
            // Add the token to the URL, because we can't add it to the JSON data:
            options.url += ((options.url.indexOf("?") === -1) ? "?" : "&") + token.serialize();
        } else if (typeof options.data === 'string' && options.data.indexOf(tokenName) === -1) {
            // Append to the data string:
            options.data += (options.data ? "&" : "") + token.serialize();
        }
    }
});

Answer 6

1.Define Function to get Token from server

@function
{

        public string TokenHeaderValue()
        {
            string cookieToken, formToken;
            AntiForgery.GetTokens(null, out cookieToken, out formToken);
            return cookieToken + ":" + formToken;                
        }
}

2.Get token and set header before send to server

var token = '@TokenHeaderValue()';    

       $http({
           method: "POST",
           url: './MainBackend/MessageDelete',
           data: dataSend,
           headers: {
               'RequestVerificationToken': token
           }
       }).success(function (data) {
           alert(data)
       });

3. Onserver Validation on HttpRequestBase on method you handle Post/get

        string cookieToken = "";
        string formToken = "";
        string[] tokens = Request.Headers["RequestVerificationToken"].Split(':');
            if (tokens.Length == 2)
            {
                cookieToken = tokens[0].Trim();
                formToken = tokens[1].Trim();
            }
        AntiForgery.Validate(cookieToken, formToken);