Getting started with the Microsoft Purview extension for Mozilla Firefox

This week is sort of a follow-up on last week. Last week the focus was on getting started with the Microsoft Purview extension for Google Chrome, while this week the focus is on getting started with the Microsoft Purview extension for Mozilla Firefox. The story around the extension is pretty similar, as the Microsoft Purview extension for Mozilla Firefox extends the Endpoint data loss prevention (Endpoint DLP) capabilities to sensitive items in the Mozilla Firefox browser. And after the installation of that extension, on Windows devices, organizations get the ability to also monitor attempts to access or upload sensitive items to a Cloud service when using the Mozilla Firefox browser, and to actually enforce protective actions via data loss prevention policies. This post will provide a brief overview of the Microsoft Purview extension for Mozilla Firefox, followed with the steps to automatically configure the extension, on Windows devices, by using Microsoft Intune. This post will end with an overview of the Microsoft Purview extension after the installation and with the user experience when working with sensitive items.

Important: This post relies on the feature of importing third-party ADMX-files, which is still in public preview.

Introducing Microsoft Purview extension in Mozilla Firefox

The Microsoft Purview extension for the Mozilla Firefox browser enables organizations to audit and manage a specific list of activities that user can take on sensitive items. An overview of those activities is summarized in the table below.

Activity	Description	Policy actions
File copied to cloud	This activity detects when a user attempts to upload a sensitive item to a restricted service domain through the Mozilla Firefox browser	audit, block with override, block
File printed	This activity detects when a user attempts to print a sensitive item from the Mozilla Firefox browser to a local or network printer	audit, block with override, block
File copied to clipboard	This activity detects when a user attempts to copy and paste information from a sensitive item in the Mozilla Firefox browser into another app, process, or item.	audit, block with override, block
File copied to removable storage	This activity detects when a user attempts to copy a sensitive item or information from the Mozilla Firefox browser to removable media or USB device	audit, block with override, block
File copied to network share	This activity detects when a user attempts to copy a sensitive item or information from the Mozilla Firefox browser to a network share or mapped network drive.	audit, block with override, block

Note: Microsoft recommends to use Microsoft Edge if it’s needed to upload files in quick succession.

Installing Microsoft Purview extension in Mozilla Firefox

After being familiar with the Microsoft Purview extension in Mozilla Firefox, it’s time to look at the configuration (or installation) of the extension. Just like with Google Chrome, Administrative Templates can be used for the forced installation of an browser extension in Mozilla Firefox. The main difference, however, is that those configuration options are not available by default in Microsoft Intune. That means that the configuration would require importing the different ADMX-files for configuring Mozilla Firefox, before the configuration of Mozilla Firefox becomes available.

Importing the Mozilla Firefox ADMX-files

The first step would be importing the ADMX-files for configuring Mozilla Firefox. With that it’s important to be familiar with the dependencies of those ADMX-files, as those dependencies should be imported first. That’s also applicable for the configuration of Mozilla Firefox. The configuration requires the firefox.admx file, which depends on the mozilla.admx file. The following five steps walk through the process of importing those files.

1. Download the ADMX and ADML-files for Mozilla Firefox here
2. Open the Microsoft Intune admin center portal and navigate to Devices > Configuration 
3. On the Import ADMX tab, select Import to start the process of importing the ADMX-file and ADML-file
4. On the ADMX file upload page, as shown in Figure 1, provide the following information and click Next

• ADMX file (1): Select the mozilla.admx file to import
• ADML file for the default language (2): Select the mozilla.adml file to import
• Specify the language of the ADML file: At this moment English is selected and grayed out

4. On the Review + create page, click Create
5. Once the Status is Available, walk through step 2-4 for the firefox.admx file and the firefox.adml file

Note: Keep in mind that the challenge will be in keeping the ADMX and ADML-files up-to-date. That’s because when uploading an ADMX-file with settings that are already imported, the upload will fail with a namespace error. That includes a new version of an ADMX-file that contains the same settings as the existing ADMX-file. So, when working with third-party ADMX-files, make sure to think about how to handle updates on those ADMX-files and the related settings.

Configuring the required settings in Mozilla Firefox

After importing the different required ADMX and ADML-files, the available settings within those ADMX-files become available for configuration via Microsoft Intune. That can be achieved by using the configuration template named Imported Administrative templates. That template can be used to easily browse through the available imported settings for managing the configuration of Mozilla Firefox, including the required setting for installing the Microsoft Purview extension. That setting is Extension Management and can be configured with. The following eight steps walk through the process of configuring that specific setting in Mozilla Firefox.

1. Open the Microsoft Endpoint Manager admin center portal and navigate to Devices > Configuration
2. On the Devices | Configuration profiles page, click Create profile
3. On the Create a profile blade, provide the following information and click Create

• Platform: Select Windows 10 and later as platform
• Profile type: Select Templates > Imported Administrative templates as profile type

4. On the Basics page, provide at least a unique name and click Next
5. On the Configuration settings page, as shown in Figure 2, configure the following setting and click Next

• Navigate to Computer Settings > Mozilla > Firefox, select Extension Management (1) and specify {“microsoft.defender.browser_extension.native_message_host@microsoft.com”:{“installation_mode”: “force_installed”, “install_url”: “https://github.com/microsoft/purview/raw/main/endpointDLP/browser_extension/prod-1.1.0.212.xpi”,”updates_disabled”:false}} (2)

6. On the Scope tags page, configure the require scope tags and click Next
7. On the Assignments page, configure the required assignment and click Next
8. On the Review + create page, verify the configuration and click Create

Experiencing the Microsoft Purview extension in Mozilla Firefox

When the configuration is in place to automatically force the installation of the Microsoft Purview extension for the Mozilla Firefox browser, it’s time to experience the behavior. That experience should be experienced in two steps for the complete experience. The first step would be to simply experience the installation of the Microsoft Purview extension for Mozilla Firefox. That is pretty straightforward, as shown below in Figure 3, by simply looking at the installed extensions. It can’t be removed.

After the installation is completed successfully, it’s time to actually experience the behavior with the Microsoft Purview extension in the Mozilla Firefox browser. That requires Endpoint DLP to be configured. Once that’s in place, Microsoft provides multiple DLP scenarios to test the behavior of the Microsoft Purview extension in the Mozilla Firefox browser. For example, when preventing copying specific data to ChatGPT will result in a notification as shown below in Figure 4.

More information

For more information about the Microsoft Purview extension for Mozilla Firefox, refer to the following docs.

• Learn about the Microsoft Purview extension for Firefox | Microsoft Learn
• Get started with the Microsoft Purview extension for Firefox | Microsoft Learn
• Learn about Endpoint data loss prevention | Microsoft Learn
• Create a policy using settings catalog in Microsoft Intune | Microsoft Learn