This header enables the Cross-site scripting (XSS) filter in your browser. It checks for the presence of the X-XSS-Protection-header.

How to fix this health check

This health check can be fixed by adding a header before the response is started.

Preferable you use a security library like NWebSec.

Adding Cross-site scripting Protection using NWebSec

If you take a NuGet dependency on NWebsec.AspNetCore.Middleware/, you can use third extension methods on IApplicationBuilder.

public class Startup
{
    public void Configure(IApplicationBuilder app)
    {
        app.UseXXssProtection(options => options.EnabledWithBlockMode());

        ...
    }
}

Adding Cross-site scripting Protection using manual middleware

If you don't like to have a dependency on third party libraries. You can add the following custom middleware to the request pipeline.

public class Startup
{
    public void Configure(IApplicationBuilder app)
    {
        app.Use(async (context, next) =>
        {
            context.Response.Headers.Add("X-Xss-Protection", "1; mode=block");
            await next();
        });

       ...
    }
}

Leaving debug compilation mode enabled can severely slow down a website and take up more memory on the server.

How to fix this health check

This health check can be fixed by providing configuration on the following path: Umbraco:CMS:Hosting:Debug.

This configuration can be setup in a configuration source of your choice. This guide shows how to set it up in one of the JSON file sources.

Updating the JSON configuration

The following JSON needs to be merged into one of your JSON sources. By default the following JSON sources are used: appSettings.json and appSettings.<environment>.json, e.g. appSettings.Development.json or appSettings.Production.json.

{
  "Umbraco": {
    "CMS": {
      "Hosting": {
        "Debug": <true|false>
      }
    }
  }
}

One example that can be used for production:

{
  "Umbraco": {
    "CMS": {
      "Hosting": {
        "Debug": false
      }
    }
  }
}

Check to make sure a fixed application URL is specified. This URL is for example used when sending emails from backoffice. If this is not specified in configuration, Umbraco gets the application URL from last host used to request the application

How to fix this health check

This health check can be fixed by providing configuration on the following path: Umbraco:CMS:WebRouting:UmbracoApplicationUrl.

This configuration can be setup in a configuration source of your choice. This guide shows how to set it up in one of the JSON file sources.

Updating the JSON configuration

The following JSON needs to be merged into one of your JSON sources. By default the following JSON sources are used: appSettings.json and appSettings.<environment>.json, e.g. appSettings.Development.json or appSettings.Production.json.

{
    "Umbraco": {
        "CMS": {
            "WebRouting": {
                "UmbracoApplicationUrl": "string"
            }
        }
    }
}

One example that can be used in production

{
    "Umbraco": {
        "CMS": {
            "WebRouting": {
                "UmbracoApplicationUrl": "https://www.my-custom-domain.com/"
            }
        }
    }
}

Checks to see if your site is revealing information in its headers that gives away unnecessary details about the technology used to build and host it.

How to fix this health check

This health check can be fixed by removing headers before the response is started.

Be aware these headers are often added by the server and not by the application.

Unless you publicly expose the Kestrel server (), you can't handle this directly in middleware.

Removing headers when hosted on IIS

For IIS you will need to manipulate web.config (If you don't have web.config already in your project you will need to add it at the root). Ensure to remove the custom X-Powered-By and Server header as shown in the following example.

Removing headers when hosted on Kestrel

By default Kestrel will only expose the Server header. To disable this, you have to configure Kestrel in Program.cs. You can use the UseKestrel extension method on IWebHostBuilder like in the following example.

Below is a list of guides for Health Checks in Umbraco.

Checks that your site contains a header used to protect against Multipurpose Internet Mail Extensions (MIME) sniffing vulnerabilities.

How to fix this health check

This health check can be fixed by adding a header before the response is started.

Preferable you use a security library like .

Adding Content/MIME Sniffing Protection using NWebSec

If you take a NuGet dependency on , you can use third extension methods on IApplicationBuilder.

Adding Content/MIME Sniffing Protection using manual middleware

If you don't like to have a dependency on third party libraries. You can add the following custom middleware to the request pipeline.

Checks that the web server folder and file permissions are set correctly for Umbraco to run.

How to fix this health check

This health check can be fixed by ensuring that the process running Umbraco also has write access to the listed folders and files.

Updating the file permissions on Windows

Here's an example of how to adjust permissions for a folder. This process works the same way for files.

First we see an example of an error from the health check

To fix this, we find the specified folder, from the report and choose Properties and the Security tab.

From here you can edit the permissions for a specific user or user group.

Checks if your site is allowed to be IFRAMEd by another site and thus would be susceptible to click-jacking.

How to fix this health check

This health check can be fixed by adding a header before the response is started.

Preferable you use a security library like .

Adding Click-Jacking Protection using NWebSec

If you take a NuGet dependency on , you can use third extension methods on IApplicationBuilder.

Adding Click-Jacking Protection using manual middleware

Avoid third-party library dependencies by using custom middleware added to the request pipeline.

The Settings section of the Umbraco backoffice holds a dashboard named "Health Check". It is a handy list of checks to see if your Umbraco installation is configured according to best practices. It's possible to add your custom-built health checks.

For inspiration when building your checks you can look at the checks we've , as well as our . Some examples will follow in this document.

Built-in checks

Umbraco comes with the following checks by default:

• Category Configuration

  • Macro errors (id: D0F7599E-9B2A-4D9E-9883-81C7EDC5616F) - checks that the errors are set to inline so that pages that error will still load (and shows a small error message)

  • Notification Email Settings (id: 3E2F7B14-4B41-452B-9A30-E67FBC8E1206) - checks that the "from" email address used for email notifications has been changed from its default value

• Category Data Integrity

  • Database data integrity check (id: 73DD0C1C-E0CA-4C31-9564-1DCA509788AF) - checks for data integrity issues in the Umbraco database

• Category Live Environment

  • Debug Compilation Mode (id: 61214FF3-FC57-4B31-B5CF-1D095C977D6D) - should be set to debug="false" on your live site

• Category Permissions

  • Folder & File Permissions (id: 53DBA282-4A79-4B67-B958-B29EC40FCC23) - checks that the folders and files set with write permissions that are either required or recommended can be accessed

• Category Security

  • Application URL Configuration (id: 6708CA45-E96E-40B8-A40A-0607C1CA7F28) - checks if the Umbraco application URL is configured for your site.

  • Click-Jacking Protection (id: ED0D7E40-971E-4BE8-AB6D-8CC5D0A6A5B0) - checks to see if a header or meta-tag is in place to indicate whether the site can be hosted in an IFRAME. Normally this is best set to deny permission for this to be done, to prevent what is known as attacks

  • Content/MIME Sniffing Protection (id: 1CF27DB3-EFC0-41D7-A1BB-EA912064E071) - checks that your site contains a header used to protect against Multipurpose Internet Mail Extensions (MIME) sniffing vulnerabilities

  • Cookie hijacking and protocol downgrade attacks Protection (HSTS) (id: E2048C48-21C5-4BE1-A80B-8062162DF124) - checks if your HTTPS site contains the Strict-Transport-Security Header (HSTS). If not - adds with a default of 18 weeks

  • Cross-site scripting Protection (id: F4D2B02E-28C5-4999-8463-05759FA15C3A) - checks for the presence of the X-XSS-Protection-header

  • Excessive Headers (id: 92ABBAA2-0586-4089-8AE2-9A843439D577) - checks to ensure that specific headers that can provide details about the technology used to build and host the website have been removed

  • HTTPS Configuration (id: EB66BB3B-1BCD-4314-9531-9DA2C1D6D9A7) - to determine if the current site is running on a secure connection

  • UseHttps check - when the site is running on HTTPS, Umbraco.Cms.Core.Configuration.Models.GlobalSettings.UseHttps needs to be enabled to secure the backoffice. The setting can be found under Umbraco:CMS:Global in the appsettings.json file

• Category Services

  • SMTP Settings (id: 1B5D221B-CE99-4193-97CB-5F3261EC73DF) - checks that an Simple Mail Tranfer Protocol (SMTP) server is configured and is accepting requests for sending emails

Each check returns a message indicating whether or not the issue in question has been found on the website installation. This could be an error that should be fixed, or a warning you should be aware of.

Some of them can also be rectified via the dashboard, by clicking the Fix button and in some cases providing some required information. These changes usually involve writing to configuration files that will often trigger a restart of the website.

Configuring and scheduling checks

You can view the results of health checks via the Settings section dashboard. Additionally, you can set up the checks to be run on a schedule and be notified of the results by email. It's also possible to disable certain checks if they aren't applicable in your environment.

Custom checks

You can build your own health checks. There are two types of health checks you can build: configuration checks and general checks.

Each health check is a class that needs to have a HealthCheck attribute. This attribute has a few things you need to fill in:

• GUID - a unique ID that you've generated for this specific check

• Name - give it a short name so people know what the check is for

• Description - describes what the check does in detail

• Group - this is the category for the check if you use an existing group name (like "Configuration") the check will be added in that category, otherwise a new category will appear in the dashboard

Configuration checks

• A configuration check needs to inherit from Umbraco.Cms.Core.HealthChecks.Checks.AbstractSettingsCheck

• A configuration check needs the HealthCheck attribute as noted at the start of this document

• ReadMoreLink is a link to an external guide that will help you to troubleshoot any problems

• ValueComparisonType can either be ValueComparisonType.ShouldEqual or ValueComparisonType.ShouldNotEqual

• ItemPath is the IConfiguration key path leading to the configuration value that you want to verify

• Values is a list of values that are available for this configuration item - in this example it can be RemoteOnly or On, they're both acceptable for a live site.

  • For checks using the ShouldEqual comparison method, make sure to set one of these values to IsRecommended = true.

  • Where ShouldNotEqual is used the fix will require the user to provide the correct setting

• CurrentValue is the current value from the configuration setting

• CheckSuccessMessage and CheckErrorMessage are the messages returned to the user

  • It is highly recommended to use the LocalizedTextService so these can be localized. You can add the text in ~/Config/Lang/en-US.user.xml (or whatever language you like)

An example check:

General checks

This can be anything you can think of, the results and the rectify action are entirely under your control.

• A general check needs to inherit from Umbraco.Cms.Core.HealthChecks.HealthCheck

• A general check needs the HealthCheck attribute as noted at the start of this document

• All checks run when the dashboard is loaded, this means that the GetStatus() method gets executed

  • You can return multiple status checks from GetStatus()

• A status check returns a HealthCheckStatus

  • If a HealthCheckStatus has a HealthCheckAction defined then the "Fix" button will perform that action once clicked

  • Sometimes, the button to fix something should not be called "Fix", change the Name property of a HealthCheckAction to provide a better name

  • HealthCheckAction has a Description property so that you can provide information on what clicking the "Rectify" button will do (or provide links to documentation, for example)

  • HealthCheckStatus has a few result levels:

    • StatusResultType.Success

    • StatusResultType.Error

    • StatusResultType.Warning

    • StatusResultType.Info

  • A HealthCheckAction needs to provide an alias for an action that can be picked up in the ExecuteAction method

• It is highly recommended to use the LocalizedTextService so text can be localized. You can add the text in ~/Config/Lang/en-US.user.xml (or whatever language you like)

An example check:

Custom health check notifications

Each notification method needs to implement the core interface IHealthCheckNotificationMethod and, for ease of creation, can inherit from the base class NotificationMethodBase, which itself implements the IHealthCheckNotificationMethod interface. The class must also be decorated with an instance of the HealthCheckNotificationMethod attribute. There's one method to implement - SendAsync(HealthCheckResults results). This method is responsible for taking the results of the health checks and sending them via the mechanism of your choice.

The following example shows how the core method for sending notification via email is implemented:

If a custom configuration is required for a custom notification method, the following extract can be merged in the appsettings.json file. This will enable the email notification method to be configured:

If you want to get the notifications by email, Simple Mail Transport Protocol (SMTP) settings should also be configured in the same JSON file.

Checks if your site is configured to work over HTTPS and if the Umbraco related configuration for that is correct.

How to fix this health check

This health check checks a couple of things.

First of all, it ensures that your website is running on HTTPS using a valid certificate.

Furthermore, it is used to specify the configuration on the following path: Umbraco:CMS:Global:UseHttps.

This configuration can be setup in a configuration source of your choice. This guide shows how to set it up in one of the JSON file sources.

Updating the JSON configuration

The following JSON needs to be merged into one of your JSON sources. By default the following JSON sources are used: appSettings.json and appSettings.<environment>.json, e.g. appSettings.Development.json or appSettings.Production.json.

{
    "Umbraco": {
        "CMS": {
            "Global": {
                "UseHttps": <false,true>
            }
        }
    }
}

One example that can be used:

{
    "Umbraco": {
        "CMS": {
            "Global": {
                "UseHttps": true
            }
        }
    }
}

If notifications are used, the 'from' email address should be specified and changed from the default value.

How to fix this health check

This health check can be fixed by providing configuration on the following path: Umbraco:CMS:Content:Notifications:Email.

This configuration can be setup in a configuration source of your choice. This guide shows how to set it up in one of the JSON file sources.

Updating the JSON configuration

The following JSON needs to be merged into one of your JSON sources. By default the following JSON sources are used: appSettings.json and appSettings.<environment>.json, e.g. appSettings.Development.json or appSettings.Production.json.

{
  "Umbraco": {
    "CMS": {
      "Content": {
        "Notifications": {
          "Email": "<email>"
        }
      }
    }
  }
}

One example that can be used:

{
  "Umbraco": {
    "CMS": {
      "Content": {
        "Notifications": {
          "Email": "no-reply@domain.com"
        }
      }
    }
  }
}

Checks that valid settings for sending emails are in place.

How to fix this health check

This health check can be fixed by providing configuration on the following path: Umbraco:CMS:Global:Smtp

This configuration can be setup in a configuration source of your choice. This guide shows how to set it up in one of the JSON file sources.

Updating the JSON configuration

The following JSON needs to be merged into one of your JSON sources. By default the following JSON sources are used: appSettings.json and appSettings.<environment>.json, e.g. appSettings.Development.json or appSettings.Production.json.

{
    "Umbraco": {
        "CMS": {
            "Global": {
                "Smtp": {
                    "From": "<your email>",
                    "Host": "<host>",
                    "Port": "<port>",
                    "PickupDirectoryLocation": "<optional directory>",
                    "Username": "<optional username>",
                    "Password": "<optional password>",
                    "DeliveryMethod": "<Network(default)|SpecifiedPickupDirectory|PickupDirectoryFromIis>",
                    "SecureSocketOptions": "<None|Auto(default)|SslOnConnect|StartTls|StartTlsWhenAvailable>"
                }
            }
        }
    }
}

An example that can be used on localhost, is if you have a local Simple Mail Transfer Protocol (SMTP) server running during development. This could be a tool like Smtp4dev.

{
    "Umbraco": {
        "CMS": {
            "Global": {
                "Smtp": {
                    "From": "my@email.com",
                    "Host": "localhost",
                    "Port": "25"
                }
            }
        }
    }
}

Checks to make sure macro errors are not set to throw a Yellow Screen Of Death (YSOD). This could prevent certain or all pages from loading.

How to fix this health check

This health check can be fixed by providing configuration on the following path: Umbraco:CMS:Content:MacroErrors.

This configuration can be setup in a configuration source of your choice. This guide shows how to set it up in one of the json file sources.

Updating the json configuration

The following json needs to be merged into one of you json sources. By default the following json sources are used: appSettings.json and appSettings.<environment>.json, e.g. appSettings.Development.json or appSettings.Production.json.

{
    "Umbraco": {
        "CMS": {
            "Content": {
                "MacroErrors": "<Inline(default)|Silent|Throw|Content>"
            }
        }
    }
}

One example that can be used in production, but is not recommended for development:

{
    "Umbraco": {
        "CMS": {
            "Content": {
                "MacroErrors": "Silent"
            }
        }
    }
}

Checks if your site, when running with HTTPS, contains the Strict-Transport-Security Header (HSTS).

How to fix this health check

This health check can be fixed by adding the Strict-Transport-Security header to responses. The header tells browsers that future requests should be made over HTTPS only.

Using the UseHsts extension method

ASP.NET Core implements HSTS with the UseHsts extension method.

You can add UseHsts after the env.IsDevelopment() check in Startup.cs.

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    if (env.IsDevelopment())
    {
        app.UseDeveloperExceptionPage();
    }
    else
    {
        app.UseHsts();
    }
    //...
}

This example only enables HSTS if the app is not running in development mode. UseHsts isn't recommended in development because the HSTS settings are highly cacheable by browsers.

Full details of UseHsts, and additional configuration, can be found in the ASP.NET Core documentation.