Comment supprimer les en-têtes de réponse IIS/ASP.NET ?

Vérifier ce blog . N'utilisez pas de code pour supprimer les en-têtes de réponse. Il est instable selon Microsoft

Utilisez plutôt la section Web.config custom Headers :

<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>

J'utilise une combinaison de Web.config y Global.asax.cs pour se débarrasser de tous les en-têtes personnalisés, y compris les en-têtes suivants :

• Serveur
• X-AspNet-Version
• X-AspNetMvc-Version

Web.config :

<system.web> 
  <httpRuntime enableVersionHeader="false"/> 
</system.web>
<system.webServer>
   <httpProtocol>
      <customHeaders>
         <clear />
      </customHeaders>
   </httpProtocol>
</system.webServer> 

Global.asax.cs :

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

Voir aussi https://stackoverflow.com/a/20739875/1678525