Rectangle 27 14

I was just implementing this actual problem in my current project. i did it for all ajax-POSTs that needed an authenticated user.

First off i decided to hook my jquery ajax calls so i do not to repeat myself too often. this javascript snippet ensures all ajax (post) calls will add my request validation token to the request. Note: the name __RequestVerificationToken is used by the .Net framework so i can utilize the standard Anti-CSRF features as shown below.

$(document).ready(function () {
    var securityToken = $('[name=__RequestVerificationToken]').val();
    $('body').bind('ajaxSend', function (elm, xhr, s) {
        if (s.type == 'POST' && typeof securityToken != 'undefined') {
            if (s.data.length > 0) {
                s.data += "&__RequestVerificationToken=" + encodeURIComponent(securityToken);
            }
            else {
                s.data = "__RequestVerificationToken=" + encodeURIComponent(securityToken);
            }
        }
    });
});

In your Views where you need the token to be available to the above javascript just use the common HTML-Helper. You can basically add this code whereever you want. I placed it within a if(Request.IsAuthenticated) statement:

@Html.AntiForgeryToken() // you can provide a string as salt when needed which needs to match the one on the controller

In your controller simply use the standard ASP.Net MVC Anti-CSRF mechanism. I did it like this (though i actually used Salt).

[HttpPost]
[Authorize]
[ValidateAntiForgeryToken]
public JsonResult SomeMethod(string param)
{
    // do something
    return Json(true);
}

With Firebug or a similar tool you can easily see how your POST requests now have a __RequestVerificationToken parameter appended.

asp.net mvc - jQuery Ajax calls and the Html.AntiForgeryToken() - Stac...

asp.net-mvc ajax asp.net-mvc-2 csrf antiforgerytoken
Rectangle 27 14

I was just implementing this actual problem in my current project. i did it for all ajax-POSTs that needed an authenticated user.

First off i decided to hook my jquery ajax calls so i do not to repeat myself too often. this javascript snippet ensures all ajax (post) calls will add my request validation token to the request. Note: the name __RequestVerificationToken is used by the .Net framework so i can utilize the standard Anti-CSRF features as shown below.

$(document).ready(function () {
    var securityToken = $('[name=__RequestVerificationToken]').val();
    $('body').bind('ajaxSend', function (elm, xhr, s) {
        if (s.type == 'POST' && typeof securityToken != 'undefined') {
            if (s.data.length > 0) {
                s.data += "&__RequestVerificationToken=" + encodeURIComponent(securityToken);
            }
            else {
                s.data = "__RequestVerificationToken=" + encodeURIComponent(securityToken);
            }
        }
    });
});

In your Views where you need the token to be available to the above javascript just use the common HTML-Helper. You can basically add this code whereever you want. I placed it within a if(Request.IsAuthenticated) statement:

@Html.AntiForgeryToken() // you can provide a string as salt when needed which needs to match the one on the controller

In your controller simply use the standard ASP.Net MVC Anti-CSRF mechanism. I did it like this (though i actually used Salt).

[HttpPost]
[Authorize]
[ValidateAntiForgeryToken]
public JsonResult SomeMethod(string param)
{
    // do something
    return Json(true);
}

With Firebug or a similar tool you can easily see how your POST requests now have a __RequestVerificationToken parameter appended.

asp.net mvc - jQuery Ajax calls and the Html.AntiForgeryToken() - Stac...

asp.net-mvc ajax asp.net-mvc-2 csrf antiforgerytoken
Rectangle 27 4

The current user is stored in the anti-forgery token in the form data and compared with the current user on postback.

You should be able to pull out the form token on postback in the same way Phil Haack does it in this post.

Then use the AntiForgeryDataSerializer class to deserialize the token, update the current user, serialize it again and put it back in the form before it's checked. Or replace the validate method entirely using your own attribute.

Alternatively, instead of updating it on the main forms postback, you could try send the updated token back with the password ajax request and update the form. Either way the basic approach is the same, deserialize, update user, serialize, replace token.

string antiForgeryTokenName = AntiForgeryData.GetAntiForgeryTokenName(null);
string text = context.Request.Form[antiForgeryTokenName];
AntiForgeryDataSerializer serializer = new AntiForgeryDataSerializer();

AntiForgeryData antiForgeryData = serializer.Deserialize(text); 
antiForgeryData.Username = AntiForgeryData.GetUsername(context.User);
string newToken = serializer.Serialize(antiForgeryData);

The general idea works to perfection. See my reflection code above. context is of course HttpContext. The only problem is that after sign in, context.User is not updated. However the antiForgeryDate.Username is nothing out of the ordinary. In my case it's simply the email I signed in with (empty string if not signed in). So the GetUsername call is really not necessary.

Also if like me you're posting not Json but form-data, Phil's Haack is not necessary.

asp.net mvc - AntiForgeryToken invalid after sign in - Stack Overflow

asp.net-mvc asp.net-mvc-3 antiforgerytoken csrf-protection
Rectangle 27 6

You will need to clear and redo any existing form token you have upon login. This means your login code will have to either refresh the current page (kinda kills the ajax portion of it eh), your own token implementation, or you will need to refresh your token. It is possible to request a partial view, extract the token, and update your form. You could actually have a restful url which returns nothing but a token to an authenticated user. One may argue this is a security issue, but I don't believe so because it is simply an easier way to get a token rather than requesting any view -partial or otherwise.

You should be able to easily get the token instances to replace via:

Why would you have a token on the form if the user isn't logged in. You allow the same form to be 'operated' while not logged in and logged in? Most sites on the net even in this case will redirect for a login. Am I understanding this correctly? If so, you may want to consider skipping the token here or use a second type of token for unauthenticated users. You I believe are saying an unauthenticated user can already submit something in the application - again if I understand this correctly - without being authenticated.

As for your last question, why do I need a token for unauthenticated users, please see my answer to Ben's comment. I'll try to create a partial view with a token and update you with the results. Sounds like a good idea!

asp.net mvc - MVC3 AntiForgeryToken breaks on Ajax login - Stack Overf...

asp.net-mvc ajax asp.net-mvc-3 security antiforgerytoken
Rectangle 27 6

The idea behind the AntiForgeryToken is to prevent data being posted from a "fake" source. An attacker using a fake (forged) form can trick the user to submit any kind of data using their current session context. As you can imagine this can do quite a lot of damage.

A way to prevent this is to have a hidden field on your forms containing user specific data(something random) that is stored in the session, so that the bad guys can't forge it. In this case when a user posts the data, but doesn't have the user specific token, you can treat is as being malicious.

I think you have a misconception that the anti forgery token is about detecting whether the data posted has been "tempered" with, which it is not.

i want to show a custom message or redirect user to a page when action method will call and AntiForgeryToken validation check will faul means something got forge by attacker. so just guide me how to catch when AntiForgeryToken validation will fail at action method end. thanks

@Thomas The easiest would be to add a [ValidateAntiForgeryToken] attribute to your action method. This will throw an exception if the token was forged. In case you want to detect when this happens you can catch the exception in your Global.asax and do whatever you need to there.

asp.net mvc 3 - how AntiForgeryToken() works in MVC and how to retriev...

asp.net-mvc-3
Rectangle 27 1

Yes It is possible the way you performed. But you can extend the protection by extending current implementation of Anti-forgery Token by adding other hidden/encrypted fields which consists agent information.

CSRF and ValidateAntiForgeryToken in ASP.Net mvc? - Stack Overflow

asp.net-mvc csrf antiforgerytoken
Rectangle 27 9

The one limitation we ran into with the default implementation was the lack of out-of-the-box support for AJAX calls. The hidden field approach works for sites that primarily deal with traditional form POSTs; but, not quite for AJAX heavy sites like SO.

We implemented the approach outlined in this CodeThinked blog post and we couldn't be happier. It looks like Phil Haack also supports this approach, based on his oct 2011 blog post

  • if you are running a web-farm, you should, of course use a static machinekey in your Web.config
  • Make sure all your servers have this KB installed. Otherwise, you may run into machinekey validation issues

Any reason not to trust ASP.NET AntiForgeryToken? - Stack Overflow

asp.net-mvc asp.net-mvc-3 csrf antiforgerytoken
Rectangle 27 21

ASP.NET/MVC provides a mechanism for this: you can add to to a collection of filters on the global FilterProviders object. This allows you to target some controllers and not others, adding the needed security feature.

First, we need to implement an IFilterProvider. Below, you can find Phil Haack's Conditional Filter Provider class. Begin by adding this class to your project.

public class ConditionalFilterProvider : IFilterProvider
{
    private readonly
      IEnumerable<Func<ControllerContext, ActionDescriptor, object>> _conditions;

    public ConditionalFilterProvider(
      IEnumerable<Func<ControllerContext, ActionDescriptor, object>> conditions)
    {
        _conditions = conditions;
    }

    public IEnumerable<Filter> GetFilters(
        ControllerContext controllerContext,
        ActionDescriptor actionDescriptor)
    {
        return from condition in _conditions
               select condition(controllerContext, actionDescriptor) into filter
               where filter != null
               select new Filter(filter, FilterScope.Global, null);
    }
}

Then, add code to Application_Start that adds a new ConditionalFilterProvider to the global FilterProviders collection that ensures that all POST controller methods will require the AntiForgeryToken.

IEnumerable<Func<ControllerContext, ActionDescriptor, object>> conditions = 
    new Func<ControllerContext, ActionDescriptor, object>[] {
    // Ensure all POST actions are automatically 
    // decorated with the ValidateAntiForgeryTokenAttribute.

    ( c, a ) => string.Equals( c.HttpContext.Request.HttpMethod, "POST",
    StringComparison.OrdinalIgnoreCase ) ?
    new ValidateAntiForgeryTokenAttribute() : null
};

var provider = new ConditionalFilterProvider(conditions);

// This line adds the filter we created above
FilterProviders.Providers.Add(provider);

If you implement the two pieces of code above, your MVC application should require the AntiForgeryToken for every POST to the site. You can try it out on Phil Haack's CSRF example web site - once protected, the CSRF attack will throw System.Web.Mvc.HttpAntiForgeryException without having to add the [ValidateAntiForgeryToken] annotation. This rules out a whole host of "forgetful programmer" related vulnerabilities.

Will this approach work with ajax post?

This question is specific to MVC4 but I have a feeling this could also work in older versions like 3, is that true?

c# - How to protect against CSRF by default in ASP.NET MVC 4? - Stack ...

c# csrf asp.net-mvc-4
Rectangle 27 1

It's a good rule to add it to every POST action. Even if you think the action doesn't need it. Because you don't know what changes to that action may occur in the future.

Where I work, it's a standard that we all follow.

Do i need to add an AntiForgeryToken to every POST request in ASP.NET ...

asp.net asp.net-mvc security
Rectangle 27 4

AntiForgeryToken

In your view you need the token so that it is available to JavaScript.Add following line the above javascript just use the common HTML-Helper.

@Html.AntiForgeryToken()
$(document).ready(function () {
    var securityToken = $('[name=__RequestVerificationToken]').val();
    $('body').bind('ajaxSend', function (elm, xhr, s) {
        if (s.type == 'POST' && typeof securityToken != 'undefined') {
            if (s.data.length > 0) {
                s.data += "&__RequestVerificationToken=" + encodeURIComponent(securityToken);
            }
            else {
                s.data = "__RequestVerificationToken=" + encodeURIComponent(securityToken);
            }
        }
    });
});

And in you controller simply add standard ASP.Net MVC Anti-CSRF mechanism. like

[HttpPost]
[Authorize]
[ValidateAntiForgeryToken]
public JsonResult YourMethod(string param)
{
    // do whatever
    return Json(true);
}

asp.net mvc - how to stop action method being invoked - Stack Overflow

asp.net-mvc-3
Rectangle 27 2

$(form).serialize() takes the form's controls and turns them in to a JavaScript object. then, but calling JSON.stringify you're wrapping the entire object in to a string. So now, a potential payload of the following:

{
  "__RequestVerificationToken": "X3APKURbjYGUYqY2qg1VdbYl50eVNzd7TJLYKCGC-awgkK7iNH_W6bVOw7C8zHDlygP0rVO2K4TLn5KE9CYsQN8VN1DbOOV0KzMGT7xso3o1",
  "UserName": "theUserName",
  "Password": "thePassword",
  "ConfirmPassword": "thePassword",
  "DisplayName": "theDisplayName",
  "Email": "theEmail"
}

Which would be received in as 6 separate parameters is now wrapped in one big string, which is only 1 parameter now.

Advice? Remove the JSON.stringify and just the AJAX call pass off as normal. Then ValidateAntiForgeryTokenAttribute can see the __RequestVerificationToken parameter come in instead of being masked as a string.

Moving ASP.NET MVC Register view to jQuery Dialog - missing Antiforger...

jquery asp.net-mvc asp.net-mvc-4 jquery-dialog antiforgerytoken
Rectangle 27 2

If all you are worried about is the user typing in the URL, then using the HttpPost attribute should prevent your action from being called that way:-

[HttpPost]
public ActionResult AddToCart(int id)
{

This prevents GET requests from calling that action. It doesn't however stop someone writing a dummy form and POSTing to your action.

If you are worried about something a little more malicious, you might want to implement some form of anti-forgery token, there's some good info on that here.

OK, so on re-reading the question the above doesn't quite address your issue.

How about a route? if you had something like the below, it would prevent ShoppingCart/Index being called and redirect the user to your site index.

routes.MapRoute(
            "ShoppingCartIndex",
            "ShoppingCart/Index",
            new { controller = "Home", action = "Index" }
        );

I don't think it's the AddToCart action that he wants to protect, it's the Index action, which is a GET.

But you're right, the AddToCart action definitely needs to be a POST. :-)

no im worried about user typing example.com/shoppingcart and see the empty shoppingCart.

If all you're worried about is an empty shopping cart page, why don't you just check the shopping cart contents in the Index action and redirect to Home if it's empty?

If it's about the cart being empty, could you check the number of items in the Index action of the ShoppingCart controller and redirect back if the quantity is zero?

Asp.net mvc How to prevent browser from calling an action method? - St...

asp.net-mvc-3
Rectangle 27 2

If all you are worried about is the user typing in the URL, then using the HttpPost attribute should prevent your action from being called that way:-

[HttpPost]
public ActionResult AddToCart(int id)
{

This prevents GET requests from calling that action. It doesn't however stop someone writing a dummy form and POSTing to your action.

If you are worried about something a little more malicious, you might want to implement some form of anti-forgery token, there's some good info on that here.

OK, so on re-reading the question the above doesn't quite address your issue.

How about a route? if you had something like the below, it would prevent ShoppingCart/Index being called and redirect the user to your site index.

routes.MapRoute(
            "ShoppingCartIndex",
            "ShoppingCart/Index",
            new { controller = "Home", action = "Index" }
        );

I don't think it's the AddToCart action that he wants to protect, it's the Index action, which is a GET.

But you're right, the AddToCart action definitely needs to be a POST. :-)

no im worried about user typing example.com/shoppingcart and see the empty shoppingCart.

If all you're worried about is an empty shopping cart page, why don't you just check the shopping cart contents in the Index action and redirect to Home if it's empty?

If it's about the cart being empty, could you check the number of items in the Index action of the ShoppingCart controller and redirect back if the quantity is zero?

Asp.net mvc How to prevent browser from calling an action method? - St...

asp.net-mvc-3
Rectangle 27 1

@Html.AntiForgeryToken()

I don't see the ValidateAntiForgeryTokenAttribute in your action methods, so I guess it is declared at a controller level... maybe it is affecting also to GET requests? Use the attribute in your POST methods only.

Please check my question again i have updated i have problem due to migrating iis server 7 to 7.5 so what is the settings for that?

c# - Unable to Validate Data error when using ValidateAntiForgeryToken...

c# asp.net asp.net-mvc asp.net-mvc-3 iis-7.5
Rectangle 27 1

In short, you can't. Asp.net webforms controls requires viewstate and is parsed with a different "engine". Just because they're both Microsoft and .Net doesn't necessarily mean they are compatible. That doesn't mean running them together is impossible though.

You could always use a standard .aspx page which references your master page, and inside have an ajax driven content area. This content area could be refreshed with the returned ActionResults of your MVC controllers. So while it would look like you're going to mysite.com/default.aspx, the content would really be coming from mysite.com/Home/Index (or wherever you keep your default "home"). They would still be completely separate entities though, and any manipulation of controls for one by the other could result in an invalid viewstate in the masterr or a failure of an AntiForgeryToken.

c# - How to use Master Page from Web Forms in ASP.NET MVC Area - Stack...

c# asp.net-mvc razor
Rectangle 27 0

AntiForgeryToken

In your view you need the token so that it is available to JavaScript.Add following line the above javascript just use the common HTML-Helper.

@Html.AntiForgeryToken()
$(document).ready(function () {
    var securityToken = $('[name=__RequestVerificationToken]').val();
    $('body').bind('ajaxSend', function (elm, xhr, s) {
        if (s.type == 'POST' && typeof securityToken != 'undefined') {
            if (s.data.length > 0) {
                s.data += "&__RequestVerificationToken=" + encodeURIComponent(securityToken);
            }
            else {
                s.data = "__RequestVerificationToken=" + encodeURIComponent(securityToken);
            }
        }
    });
});

And in you controller simply add standard ASP.Net MVC Anti-CSRF mechanism. like

[HttpPost]
[Authorize]
[ValidateAntiForgeryToken]
public JsonResult YourMethod(string param)
{
    // do whatever
    return Json(true);
}

asp.net mvc - how to stop action method being invoked - Stack Overflow

asp.net-mvc-3
Rectangle 27 0

I believe this is occurring because the users are double-clicking the submit button on the form. At least that's EXACTLY the case on my site.

Same here. Excerpt from most popular answer on linked question: I just removed the validation attribute. My site is always SSL and I'm not overly concerned about the risk. I just need it to work right now. Another solution would be disabling the button with javascript.

asp.net mvc - MVC 4 provided anti-forgery token was meant for user "" ...

asp.net-mvc asp.net-mvc-4 razor antiforgerytoken
Rectangle 27 0

The one limitation we ran into with the default implementation was the lack of out-of-the-box support for AJAX calls. The hidden field approach works for sites that primarily deal with traditional form POSTs; but, not quite for AJAX heavy sites like SO.

We implemented the approach outlined in this CodeThinked blog post and we couldn't be happier. It looks like Phil Haack also supports this approach, based on his oct 2011 blog post

  • if you are running a web-farm, you should, of course use a static machinekey in your Web.config
  • Make sure all your servers have this KB installed. Otherwise, you may run into machinekey validation issues

Any reason not to trust ASP.NET AntiForgeryToken? - Stack Overflow

asp.net-mvc asp.net-mvc-3 csrf antiforgerytoken
Rectangle 27 0

The idea behind the AntiForgeryToken is to prevent data being posted from a "fake" source. An attacker using a fake (forged) form can trick the user to submit any kind of data using their current session context. As you can imagine this can do quite a lot of damage.

A way to prevent this is to have a hidden field on your forms containing user specific data(something random) that is stored in the session, so that the bad guys can't forge it. In this case when a user posts the data, but doesn't have the user specific token, you can treat is as being malicious.

I think you have a misconception that the anti forgery token is about detecting whether the data posted has been "tempered" with, which it is not.

i want to show a custom message or redirect user to a page when action method will call and AntiForgeryToken validation check will faul means something got forge by attacker. so just guide me how to catch when AntiForgeryToken validation will fail at action method end. thanks

@Thomas The easiest would be to add a [ValidateAntiForgeryToken] attribute to your action method. This will throw an exception if the token was forged. In case you want to detect when this happens you can catch the exception in your Global.asax and do whatever you need to there.

asp.net mvc 3 - how AntiForgeryToken() works in MVC and how to retriev...

asp.net-mvc-3
Rectangle 27 0

Using a salt is always recommended but also limiting the token by domain and path will make your token more secure and per-page unique.

Thanks, but that doesn't really address the issue of per-request token values.

Sorry, but -1 for "If you don't have XSS vulnerabilities this problem is not going to be a big mess in your web site" as that's just plain wrong. CSRF attacks can be completely external to your application, they just need the user to still have a valid authentication cookie.

security - Is it possible to make the AntiForgeryToken value in ASP.NE...

asp.net-mvc security antiforgerytoken