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Showing posts from January, 2019

Hardware fingerprinting with a web browser

While I was updating jQuery Fancy File Uploader to support recording video and audio from webcams, microphones, and other media sources, I ran into an interesting web browser security related problem that appears to affect all major web browsers that support the MediaRecorder API . From the Developer Tools console of your favorite web browser, run this one-liner: navigator.mediaDevices.enumerateDevices().then(function(devices) { console.log(devices); }); Then go to another page on the same domain and repeat the process. Try it in a new tab. As of this date, in both Firefox and Chrome (untested in Edge), it looks like the 'deviceId' of each attached hardware audio/video device remains static across a domain during a single browser session. Since a lot of people leave their web browsers open for long periods of time, this information can be used to track a user's activity across a single domain without using cookies or localStorage. The user is also not alerted to