# Beyond Cookie Monster Amnesia: Real World Persistent Online Tracking

## TL;DR

This paper investigates the prevalence of browser fingerprinting on popular websites, revealing that about 69% potentially use it, especially third-party fingerprinting, and introduces FingerprintAlert, a tool to detect and block such tracking.

## Contribution

It provides empirical data on real-world browser fingerprinting prevalence and details the information collected, along with a new browser extension to detect and block fingerprinting.

## Key findings

- Approximately 69% of popular websites engage in fingerprinting.
- Third-party fingerprinting is more common and potentially more privacy-invasive.
- FingerprintAlert can detect and block fingerprinting attempts.

## Abstract

Browser fingerprinting is a relatively new method of uniquely identifying browsers that can be used to track web users. In some ways it is more privacy-threatening than tracking via cookies, as users have no direct control over it. A number of authors have considered the wide variety of techniques that can be used to fingerprint browsers; however, relatively little information is available on how widespread browser fingerprinting is, and what information is collected to create these fingerprints in the real world. To help address this gap, we crawled the 10,000 most popular websites; this gave insights into the number of websites that are using the technique, which websites are collecting fingerprinting information, and exactly what information is being retrieved. We found that approximately 69\% of websites are, potentially, involved in first-party or third-party browser fingerprinting. We further found that third-party browser fingerprinting, which is potentially more privacy-damaging, appears to be predominant in practice. We also describe \textit{FingerprintAlert}, a freely available browser extension we developed that detects and, optionally, blocks fingerprinting attempts by visited websites.