How to remove ASP.Net MVC Default HTTP Headers?

Question

Each page in an MVC application I'm working with sets these HTTP headers in responses:

X-Powered-By: ASP.NET
X-AspNet-Version: 2.0.50727
X-AspNetMvc-Version: 2.0

How do I prevent these from showing?

Answer 1

X-Powered-By is a custom header in IIS. Since IIS 7, you can remove it by adding the following to your web.config:

<system.webServer>
  <httpProtocol>
    <customHeaders>
      <remove name="X-Powered-By" />
    </customHeaders>
  </httpProtocol>
</system.webServer>

This header can also be modified to your needs, for more information refer to http://www.iis.net/ConfigReference/system.webServer/httpProtocol/customHeaders

---

Add this to web.config to get rid of the X-AspNet-Version header:

<system.web>
  <httpRuntime enableVersionHeader="false" />
</system.web>

---

Finally, to remove X-AspNetMvc-Version, edit Global.asax.cs and add the following in the Application_Start event:

protected void Application_Start()
{
    MvcHandler.DisableMvcResponseHeader = true;
}

---

You can also modify headers at runtime via the Application_PreSendRequestHeaders event in Global.asax.cs. This is useful if your header values are dynamic:

protected void Application_PreSendRequestHeaders(object source, EventArgs e)
{
      Response.Headers.Remove("foo");
      Response.Headers.Add("bar", "quux");
}

Answer 2

You can also remove them by adding code to your global.asax file:

 protected void Application_PreSendRequestHeaders(object sender, EventArgs e)
 {
   HttpContext.Current.Response.Headers.Remove("X-Powered-By");
   HttpContext.Current.Response.Headers.Remove("X-AspNet-Version");
   HttpContext.Current.Response.Headers.Remove("X-AspNetMvc-Version");
   HttpContext.Current.Response.Headers.Remove("Server");
 }

Answer 3

I found this configuration in my web.config which was for a New Web Site... created in Visual Studio (as opposed to a New Project...). Since the question states a ASP.NET MVC application, not as relevant, but still an option.

<system.webServer>
  <httpProtocol>
    <customHeaders>
      <clear />
      <remove name="X-Powered-By" />
    </customHeaders>
   </httpProtocol>
</system.webServer>

Update: Also, Troy Hunt has an article titled Shhh… don’t let your response headers talk too loudly with detailed steps on removing these headers as well as a link to his ASafaWeb tool for scanning for them and other security configurations.

Answer 4

.NET Core

To remove the Server header, within the Program.cs file, add the following option:

.UseKestrel(opt => opt.AddServerHeader = false)

For dot net core 1, put add the option inside the .UseKestrel() call. For dot net core 2, add the line after UseStartup().

To remove X-Powered-By header, if deployed to IIS, edit your web.config and add the following section inside the system.webServer tag:

<httpProtocol>
    <customHeaders>
        <remove name="X-Powered-By" />
    </customHeaders>
</httpProtocol>

.NET 4.5.2

To remove the Server header, within your global.asax file add the following:

    protected void Application_BeginRequest(object sender, EventArgs e)
    {
        string[] headers = { "Server", "X-AspNet-Version" };

        if (!Response.HeadersWritten)
        {
            Response.AddOnSendingHeaders((c) =>
            {
                if (c != null && c.Response != null && c.Response.Headers != null)
                {
                    foreach (string header in headers)
                    {
                        if (c.Response.Headers[header] != null)
                        {
                            c.Response.Headers.Remove(header);
                        }
                    }
                }
            });
        }

    }

Pre .NET 4.5.2

Add the following c# class to your project:

public class RemoveServerHeaderModule : IHttpModule
{
    public void Init(HttpApplication context)
    {
        context.PreSendRequestHeaders += OnPreSendRequestHeaders;
    }

    public void Dispose() { }

    void OnPreSendRequestHeaders(object sender, EventArgs e)
    {
        HttpContext.Current.Response.Headers.Remove("Server");
    }
}

and then within your web.config add the following <modules> section:

<system.webServer>
    ....
 <modules>
    <add name="RemoveServerHeaderModule" type="MyNamespace.RemoveServerHeaderModule" />
 </modules>

However I had a problem where sub-projects couldn't find this module. Not fun.

Removing X-AspNetMvc-Version header

To remove the ''X-AspNetMvc-Version'' tag, for any version of .NET, modify your ''web.config'' file to include:

<system.web>
...
   <httpRuntime enableVersionHeader="false" />
...
</system.web>

Thanks Microsoft for making this unbelievably difficult. Or maybe that was your intention so that you could track IIS and MVC installs across the world ...

Answer 5

As described in Cloaking your ASP.NET MVC Web Application on IIS 7, you can turn off the X-AspNet-Version header by applying the following configuration section to your web.config:

<system.web> 
  <httpRuntime enableVersionHeader="false"/> 
</system.web>

and remove the X-AspNetMvc-Version header by altering your Global.asax.cs as follows:

protected void Application_Start() 
{ 
    MvcHandler.DisableMvcResponseHeader = true; 
}

As described in Custom Headers You can remove the "X-Powered-By" header by applying the following configuration section to your web.config:

<system.webServer>
   <httpProtocol>
      <customHeaders>
         <clear />
      </customHeaders>
   </httpProtocol>
</system.webServer>

There is no easy way to remove the "Server" response header via configuration, but you can implement an HttpModule to remove specific HTTP Headers as described in Cloaking your ASP.NET MVC Web Application on IIS 7 and in how-to-remove-server-x-aspnet-version-x-aspnetmvc-version-and-x-powered-by-from-the-response-header-in-iis7.

Answer 6

As shown on Removing standard server headers on Windows Azure Web Sites page, you can remove headers with the following:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <system.webServer>
    <httpProtocol>
      <customHeaders>
        <clear />
      </customHeaders>
    </httpProtocol>
    <security>
      <requestFiltering removeServerHeader="true"/>
    </security>
  </system.webServer>
  <system.web>
    <httpRuntime enableVersionHeader="false" />
  </system.web>
</configuration>

This removes the Server header, and the X- headers.

This worked locally in my tests in Visual Studio 2015.

Additional References:

• IIS Request Filtering
• HttpRuntimeSection Class

Answer 7

In Asp.Net Core you can edit the web.config files like so:

<httpProtocol>
  <customHeaders>
    <remove name="X-Powered-By" />
  </customHeaders>
</httpProtocol>

You can remove the server header in the Kestrel options:

            .UseKestrel(c =>
            {
                // removes the server header
                c.AddServerHeader = false;
            }) 

Answer 8

Check this blog Don't use code to remove headers. It is unstable according Microsoft

My take on this:

<system.webServer>          
    <httpProtocol>
    <!-- Security Hardening of HTTP response headers -->
    <customHeaders>
        <!--Sending the new X-Content-Type-Options response header with the value 'nosniff' will prevent 
                Internet Explorer from MIME-sniffing a response away from the declared content-type. -->
        <add name="X-Content-Type-Options" value="nosniff" />

        <!-- X-Frame-Options tells the browser whether you want to allow your site to be framed or not. 
                 By preventing a browser from framing your site you can defend against attacks like clickjacking. 
                 Recommended value "x-frame-options: SAMEORIGIN" -->
        <add name="X-Frame-Options" value="SAMEORIGIN" />

        <!-- Setting X-Permitted-Cross-Domain-Policies header to “master-only” will instruct Flash and PDF files that 
                 they should only read the master crossdomain.xml file from the root of the website. 
                 https://www.adobe.com/devnet/articles/crossdomain_policy_file_spec.html -->
        <add name="X-Permitted-Cross-Domain-Policies" value="master-only" />

        <!-- X-XSS-Protection sets the configuration for the cross-site scripting filter built into most browsers. 
                 Recommended value "X-XSS-Protection: 1; mode=block". -->
        <add name="X-Xss-Protection" value="1; mode=block" />

        <!-- Referrer-Policy allows a site to control how much information the browser includes with navigations away from a document and should be set by all sites. 
                 If you have sensitive information in your URLs, you don't want to forward to other domains 
                 https://scotthelme.co.uk/a-new-security-header-referrer-policy/ -->
        <add name="Referrer-Policy" value="no-referrer-when-downgrade" />

        <!-- Remove x-powered-by in the response header, required by OWASP A5:2017 - Do not disclose web server configuration -->
        <remove name="X-Powered-By" />

        <!-- Ensure the cache-control is public, some browser won't set expiration without that  -->
        <add name="Cache-Control" value="public" />
    </customHeaders>
</httpProtocol>

<!-- Prerequisite for the <rewrite> section
            Install the URL Rewrite Module on the Web Server https://www.iis.net/downloads/microsoft/url-rewrite -->
<rewrite>
    <!-- Remove Server response headers (OWASP Security Measure) -->
    <outboundRules rewriteBeforeCache="true">
        <rule name="Remove Server header">
            <match serverVariable="RESPONSE_Server" pattern=".+" />

            <!-- Use custom value for the Server info -->
            <action type="Rewrite" value="Your Custom Value Here." />
        </rule>
    </outboundRules>
</rewrite>
</system.webServer>

Answer 9

For the sake of completeness, there is another way to remove the Server header, using regedit.

See this MSDN blog.

Create a DWORD entry called DisableServerHeader in the following Registry key and set the value to 1.

HKLM\SYSTEM\CurrentControlSet\Services\HTTP\Parameters

I'd rather find a proper solution using the Web.config, but using <rewrite> is not good because it requires the rewrite module to be installed, and even then it won't really remove the header, just empty it.

Answer 10

You can change any header or anything in Application_EndRequest() try this

protected void Application_EndRequest()
{
    // removing excessive headers. They don't need to see this.
    Response.Headers.Remove("header_name");
}

Answer 11

The X-Powered-By header is added by IIS to the HTTP response, so you can remove it even on server level via IIS Manager:

You can use the web.config directly:

<system.webServer>
   <httpProtocol>
     <customHeaders>
       <remove name="X-Powered-By" />
     </customHeaders>
   </httpProtocol>
</system.webServer>

Answer 12

These directions apply to IIS 10.0 only.

1. Open the web.config file located in the root directory for the Orion website.

2. Configure requestFiltering in the web.config system.webServer node:

   
   <security>
       <requestFiltering removeServerHeader ="true" />
   </security>
   
   

3. Save the file and restart your IIS app.

Full code with Powered By removing:

  <system.webServer>
    <security>
      <requestFiltering removeServerHeader="true" />
    </security>
    <httpProtocol>
      <customHeaders>
        <remove name="X-Powered-By" />
      </customHeaders>
    </httpProtocol>
  </system.webServer>