NWebsec.Mvc lets you configure NWebsec through MVC ActionFilter attributes. MVC 3 or newer is supported. By decorating controllers and actions with attributes, the NWebsec configuration is overridden. This is how it works:

NWebsec.Mvc depends on the NWebsec package, which includes the HttpHeaderModule. This module relies on its Configuration, if there is any. Now, the attributes in NWebsec.Mvc lets you override the HttpHeaderModule’s configuration, here’s the order in which the final configuration is calculated:

  1. Web.config
  2. MVC global filter
  3. MVC controller
  4. MVC action

This gives a fair amount of flexibility. Do your stuff in config or in MVC, or both. You decide!

The attributes

Most elements from the Configuration have an MVC attribute counterpart.

Now back to the attributes — they are probably best explained in code. Here are the attributes registered as global filters in Global.asax in a typical MVC app:

using System.Web.Mvc;
using NWebsec.Csp;
using NWebsec.Mvc.HttpHeaders;
using NWebsec.Mvc.HttpHeaders.Csp;


public static void RegisterGlobalFilters(GlobalFilterCollection filters)
    filters.Add(new SetNoCacheHttpHeadersAttribute());
    filters.Add(new XRobotsTagAttribute() { NoIndex = true, NoFollow = true });
    filters.Add(new XContentTypeOptionsAttribute());
    filters.Add(new XDownloadOptionsAttribute());
    filters.Add(new XFrameOptionsAttribute());
    filters.Add(new XXssProtectionAttribute());
    filters.Add(new CspAttribute());
    filters.Add(new CspDefaultSrcAttribute { Self = Source.Enable });
    filters.Add(new CspScriptSrcAttribute { Self = Source.Enable });
    filters.Add(new CspReportOnlyAttribute());
    filters.Add(new CspScriptSrcReportOnlyAttribute { None = Source.Enable });

Here’s what the attributes will look like when applied to a controller and an action method:

using System.Web.Mvc;
using NWebsec.HttpHeaders;
using NWebsec.Mvc.HttpHeaders;


[XFrameOptions(Policy = XFrameOptionsPolicy.SameOrigin)]
public class HomeController : Controller

    [XFrameOptions(Policy = XFrameOptionsPolicy.Deny)]
    public ActionResult Index()
        return View();

    [SetNoCacheHttpHeaders(Enabled = false)]
    [XContentTypeOptions(Enabled = false)]
    [XDownloadOptions(Enabled = false)]
    [XFrameOptions(Policy = XFrameOptionsPolicy.Disabled)]
    [XXssProtection(Policy = XXssProtectionPolicy.Disabled)]
    [XRobotsTag(Enabled = false)]
    public ActionResult HeadersDisabled()
        return View();

Note how the Index action method is decorated with only one attribute. It has its own XFrameOptions setting, and will inherit all other attributes from the controller.

The HeadersDisabled action shows how headers can be disabled per action or controller. This lets you define a strict global security policy for your application and relax the policy where needed.