Ha, excellent point.

You could potentially leak any small piece of information by encoding it in glyph shapes. Should be enough capacity for something like MachineGUID.

It is not unique per system. As mentioned in the article, the font only changes version number between TeamViewer updates.

How do you know? The font number does not matter as the website wont see that. To check uniqueness of the fonts you would need to actually compare the content of installed font, not only the name. It would be totally possible that the installer is packed with the font, but dynamically alters it before actually installing it.

The version number is part of the font name (e.g. “TeamViewer15”). Websites can apply a list of known font names to an element and see which are available based on whether a test element changes size after applying the font.

If they are so hell bent of forcing users to pay stop offering a free version.

That would equal to fishing without a bait on the hook:)

For what possible intention though?

You render this font in a web canvas that your js can interpret. Boom, fingerprinted. That's amoral but that's really clever.

but why?

Instead of spreading ridiculous claims, why won't you just confirm your hypothesis?

All it takes is 2 ip:s and two downloads of their installer and compare checksums.

https://download.teamviewer.com/download/TeamViewer_Setup.ex...

4440facac7b7bf11478a0368ce448adc732d97ae TeamViewer_Setup.exe

The font can be generated after installation.

I don't have Windows near me to rub tests myself.

It's not. It is embedded in the installer with a sha1 of 692a2bd8cce1c4ac62f7cd505907aa8e21ab3b69, which you would have known had you actually studied the suspicious file at hand, rather than just go with the narrative posted in the blog.

You might be right, but your comments fail the "common decency" standard.

Well, they’re right, and they did the work to verify they were right, as opposed to the other people in this thread blindly making assumptions. They care more about the truth than the other posters.

Makes them more decent than the others, in my book.

They didn't, really.

Sure, the installer ships a font file, and sure, the most obvious answer is that it's just installed as is.

But my app also ships a bunch of templates, and it doesn't mean users will always see the same thing when they're loaded. The font binary could have some magic number that's replaced with a fingerprint ID.

Most likely it isn't, but the work to verify would actually involve installing TV in two different machines, and comparing the installed files.

They did, really.

If you think they're going through the hassle to ship a font file but sleight-of-hand install a different font, then why do you think they wouldn't also go through the hassle of further hide what they're doing? For instance, replace a preexisting font you wouldn't think to look at?

If you think it's honest-to-god malware, then provide evidence that it's malware. Installing a font does not make software malware. Checking for the presence of an installed font is not malware.

its a comment section / blog post, not a paper that needs violent peer review

I appreciate someone actually checking things for themselves, instead of just joining the rage party.

Have you checked that the installer does not alter the file during installation?

TeamViewer - not Teamspeak...

Thanks, updated.