Telemetry

While websites can use beacons and similar technologies to monitor a user’s behavior while visiting a site, the browser itself also may be instrumented with technology that monitors the user. This technology, called telemetry, is ostensibly designed to help browser developers improve their software and prioritize features. However, taken in the context of digital privacy, browser telemetry is just another way to track user behavior.

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Telemetry in Proprietary Browsers

By default, Google Chrome, Apple Safari, and Microsoft Edge all send telemetry data back to their respective companies. Chrome, for example, generates an instance identifier that is uniquely tied to the browser installation, which changes only when the browser is uninstalled and reinstalled. This identifier is transmitted back to Google along with various properties of the installation and the computer system. In addition, Chrome transmits every URL visited by the browser back to Google.¹ This transmission still occurs even in incognito mode, which has led to a class-action lawsuit.² Google’s privacy policy for Chrome allows them to collect this information and is subject to change at any time.³

Of the three proprietary browsers studied, Apple Safari collects and returns the least amount of telemetry data. In a manner similar to Chrome, Safari generates a unique installation identifier that is unique to the browser installation, although this identifier can change of the browser is uninstalled and reinstalled. Any URL that is typed directly into the browser’s address bar is sent to Apple as part of the telemetry data.¹ Apple’s privacy policy permits user data collection and targeted advertising, and it is subject to change at any time.⁴

Microsoft Edge is far worse than even Chrome or Safari in terms of the telemetry data it returns to the company. While the browser does generate an instance identifier at install time, it also computes a hardware identifier that is unique to the machine on which it is installed. This hardware identifier is transmitted to Microsoft, in addition to reporting all the URLs the browser loads and setting a Microsoft tracking cookie when Edge is started for the first time.¹ Some of this data collection is explicitly disclosed in the Microsoft Privacy Statement, which is also subject to change at any time.⁵

There is a pattern present with all three major proprietary browsers. All three respective companies are involved in the advertising business and the surveillance economy, although Google and Microsoft arguably have a greater stake in these ventures since both operate search engines. While the privacy policies of all 3 companies claim to protect the user’s privacy, this “protection” tends not to include protecting the user’s privacy from the company offering the browser. In addition, the companies can change the privacy policies at will without first obtaining explicit approval from each user, so the value of these privacy statements is dubious in the long run.

Telemetry in Open Source Browsers

Even though a browser might be released as open source software, it could still contain telemetry capabilities. In particular, three of the most widely used open source browsers either contain or have support for telemetry: Chromium, Mozilla Firefox, and Brave.

Chromium is the upstream open source project from which Google Chrome and Microsoft Edge are derived. At the Chromium project level, there is support for telemetry, although it is intended as a performance testing framework for Chromium developers.⁶ Some default telemetry benchmarks are apparently included in official binary builds directly from the project, although third party builds of the Chromium source code might or might not contain this code. The official Linux binary build for Chromium tries to scan for any Android devices connected to the computer using a bundled copy of the Android Debug Bridge (adb). Curiously, this bundled copy of adb is 32-bit and requires an extra library to be installed on 64-bit Linux systems.⁷ Since Google sponsors and largely controls the Chromium project, there is always potential for additional tracking features to be added.

Mozilla Firefox is another open-source browser, which ships with telemetry enabled by default. Like the proprietary browsers, Firefox generates a unique identifier at installation time (which may change upon reinstallation) and transmits any URLs typed directly into the address bar to Mozilla.¹ Mozilla is more open about its collected data, which include information about the build, some hardware properties of the computer, browser settings, a list of addons installed, and several other pieces of information.⁸

At the time of the browser telemetry study by Leith¹, the Brave browser was still a proprietary product that was found not to transmit any telemetry data.¹ However, the company behind Brave runs its own advertising system based on a cryptocurrency rewards scheme.⁹ Built-in advertising, displayed both in the browser and as desktop notifications, is included with this particular browser.¹⁰ In addition, recent versions of Brave have added analytics capabilities that are marketed as “privacy-preserving” by the company.¹¹

Community Rebuilds and Opting Out

Community-operated rebuilds of open source browsers are available with telemetry removed. The LibreWolf project is built from the source code of Firefox, but it omits the telemetry features and enables other privacy options by default.¹² The ungoogled-chromium project works to build patched versions of Chromium without any calls back to Google.¹³ Both these browsers provide much of the same upstream functionality as their parent projects, although their stricter default privacy settings can break some websites.

In some cases, it is possible to disable telemetry in the major browsers. Firefox, for example, has settings to turn off telemetry data collection and reporting. Other browsers, particularly proprietary ones like Edge, might be more limited in terms of disabling telemetry. In any case, these browsers all default to requiring an opt-out mechanism in which telemetry is on by default. It is telling that many of the same kinds of developers who are the supposed recipients of telemetry data instead champion an opt-in system for telemetry, in which no data are collected without first obtaining the user’s informed consent, as illustrated by a recent controversy over adding telemetry to the Go programming language.¹⁴

References and Further Reading

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