Chrome extensions offer you, the user, the ability to customize and control your web browsing experience. Arguably they are one of the main reasons that Google Chrome is the biggest web browser in the world by a long way. Unfortunately, however, new research indicates that some Chrome extensions may also be helping nefarious third parties track your online activity. Let’s explore this further.
A web developer named z0ccc has released details on how Google Chrome extensions can help with ‘fingerprinting’ devices so that they can then be tracked online.
These device fingerprints, or tracking hashes as they are also known, are made up of various device characteristics including GPU performance, screen resolution, hardware configuration, installed apps, and can even go down to different installed fonts. Once they have been established it is possible to use them to track a particular device’s web activity across different sites.
Unfortunately, z0ccc shared details of a new type of fingerprinting that is able to create device tracking hashes based on the different Chrome browser extensions that are installed on the device.
He reports that installed extensions cause difference in behavior that can then be recognized and tracked.
“Resources of protected extensions will take longer to fetch than resources of extensions that are not installed. By comparing the timing differences you can accurately determine if the protected extensions are installed,”
The researcher, z0ccc has created a website called Extension Fingerprints that will check all of your installed extensions against his newly discovered vulnerability. The tool is able to check against 1,170 popular extensions that are available on the Google Chrome Web Store. The more extensions a user has installed on their version of Google Chrome, the more unique their fingerprint will be, with z0ccc saying, “Having 3+ detectable extensions installed seems to always make your fingerprint very unique.”. Interestingly, however, this method does not work with Mozilla Firefox extensions as Firefox extension IDs are unique for every browser instance.
Ironically, if you are worried about privacy, Chrome has a number of extensions to help you. We can’t talk to their efficacy in combatting this particular privacy issue, but these 13 Chrome privacy extensions will offer relief to the more privacy-minded of you out there.