Firefox 75 comes with a new telemetry agent that sends information about your operating system and your default browser to Firefox every day. This guide will walk you through disabling this "feature" to protect your privacy.

For some time, Firefox has been collecting telemetry data about how you use the browser, such as the number of web pages you visit, safebrowsing information, the number of open tabs and windows, what add-ons are installed, and more.

This telemetry data is kept for 13 months and IP addresses listed in server logs are deleted every 30 days.

On my computer, Firefox has collected over 400KB of information.

Firefox now collects default browser settings data

In March, Firefox announced that they would start to gather more information about your default browser to understand changes in default browser settings.

"With Firefox 75, we’re launching a new scheduled task for Windows that will help us understand changes in default browser settings. As with all other telemetry related changes here at Mozilla, this scheduled task has gone through our data review, a process designed with user choice and privacy at its core…" Mozilla stated in a blog post.

Mozilla has broken down this process to show exactly what is being collected:

We’re collecting information related to the system’s current and previous default browser setting, as well as the operating system locale and version. This data cannot be associated with regular profile based telemetry data. If you’re interested in the schema, you can find it here.

The information we collect is sent as a background telemetry ping every 24 hours.

We’ll respect user configured telemetry opt-out settings by looking at the most recently used Firefox profile.

We’ll respect custom Enterprise telemetry related policy settings if they exist. We’ll also respect policy to specifically disable this task.

After installing Firefox 75, which was released yesterday, a new program named default-browser-agent.exe will be installed into the C:\Program Files\Mozilla Firefox\ folder that sends telemetry back to Firefox every 24 hours.

Firefox Default Browser Agent

This program is executed through a scheduled task named "Firefox Default Browser Agent" that will be configured after upgrading/installing Firefox 75. This task will be scheduled to run every 24 hours at the same time you install installed or upgraded the browser.

Firefox Default Browser Agent scheduled task

This scheduled task will execute the following command, which will gather information that includes your default browser, configured locale in the operating system, your operating system version, your previous default browser, and the currently installed version of Firefox.

C:\Program Files\Mozilla Firefox\default-browser-agent.exe do-task

Once the information is gathered, the C:\Program Files\Mozilla Firefox\pingsender.exe program will be executed to upload the data to Firefox's telemetry servers at https://incoming.telemetry.mozilla.org/submit/default-browser-agent/1/default-browser/[UID].

POST https://incoming.telemetry.mozilla.org/submit/default-browser-agent/1/default-browser/B1A04AEE-5B0E-49EB-A01A-35AE6E9EE7E6 HTTP/1.1 Date: Wed, 08 Apr 2020 05:28:23 GMT X-PingSender-Version: 1.0 User-Agent: pingsender/1.0 Host: incoming.telemetry.mozilla.org Content-Length: 153 Cache-Control: no-cache {"build_channel":"release","default_browser":"edge","os_locale":"en-US","os_version":"10.0.19041.153","previous_default_browser":"edge","version":"75.0"}

As some may consider this a violation of privacy, below are instructions on how to prevent Firefox from uploading your information and to delete the task if wanted.

How to disable Firefox's Default Browser Agent telemetry

To prevent the Firefox Default Browser Agent program from sending your default browser information, operating system information, and location, you can disable it through the browser settings and group policies.

Option 1: Disable using Firefox settings

The easiest way to prevent default-browser-agent.exe from sending your default browser information to Firefox as well as disable all other telemetry is to simply disable it in the Firefox settings.

To disable telemetry in Firefox, please follow these steps:

Click the Firefox hamburger menu button ( ) and select Options. Click on the Privacy & Security section. Scroll down to "Firefox Data Collection and Use". Uncheck 'Allow Firefox to send technical and interaction data to Mozilla' so it appears as in the image below Disable Firefox telemetry Close the settings.

With this setting disabled, no telemetry, including the default browser information, will be sent to Firefox.

Option 2: Disable using Firefox group policies

Mozilla has introduced a Windows group policy that prevents the default-browser-agent.exe executable from sending your default browser info.

To enable this policy, create the "DisableDefaultBrowserAgent" value under the HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Mozilla\Firefox Registry key and set its value to 1 as shown in the Registry file below.

You can also copy the registry file shown in the green box below and save it in Notepad as disable-def-browser.reg. Then double-click this file to import the policy into the Registry for you.

Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Mozilla\Firefox]

"DisableDefaultBrowserAgent"=dword:00000001

Once this policy is configured, when default-browser-agent.exe is executed, it will not send any of your information to Firefox's telemetry servers.

This policy works immediately after being created.

Remove the Firefox Default Browser Agent scheduled task

If you used the above steps to disable the Default Browser Agent, all you have done is prevent the program from uploading your info.

It will still, though, continue to execute every 24 hours due to a scheduled task name 'Firefox Default Browser Agent'.

To remove this task so that the default-browser-agent.exe is no longer executed every day, please follow these steps:

Click on the Start Menu and search for "task" and then click on the Task Schedule result when it appears. Open Task Scheduler When Task Scheduler opens, click on the arrow next to the Task Scheduler Library key to expand it. Then click on Firefox to see the Default Browser Agent scheduled task. Go to the Mozilla leaf Right-click on the Default Browser Agent task and select Delete. Delete the Default Browser Agent task The task should now be deleted and you can close the Task Scheduler.

The scheduled task has now been deleted and the default-browser-agent.exe executable will no longer be executed every day.

H/T Techdows.com