Ultimately, the problem is much bigger than /etc/machine-id since there are dozens of hardware IDs on any PC that can be used by malicious telemetry to silently to uniquely identify and track you, and the only solution to this problem currently is to make sure you really trust any software you use.
Systemd, in particular, acts a lot like malware for Linux because if you try to reset your machine-id a long list of stuff that breaks in in it. You could make a cron script to reset /etc/machine-id every day, but machine-id is so deep in the stack that you’d also have to reboot to ensure it’s updated.
Flatpaks might be the solution here. Flatpaks run in containers, they might have isolated machine-id already.
Though tbh if you don’t trust the apps on your Linux system, you have more to worry about than fingerprinting. Regular executable binaries and system packages have zero isolation, any malware can wreak havoc. Flatpaks are getting there but many apps still ask for permissions they don’t need, increasing risk.
For untrusted apps, run them in a browser (if a web-app), a container/distrobox, or a VM.
The browser itself is one of the biggest vectors of attacks here. Both Chrome and Firefox indirectly via libdbus, read your machine-id. Firefox shares browsing data and other unique info with ‘with partners, service providers, suppliers and contractors’ including Cloudflare and Google.
Well browsers are apps, just like any other app on your system. So the same advice applies. If you don’t trust chrome and firefox but you still want to run them, use a container/distrobox/VM. There are plenty of more private browsers though, like Brave or Mullvad Browser.
Web apps, on the other hand, run inside the browser sandbox, which is an entirely different environment. They don’t have access to machineid unless the browser gave it to them, for example via a browser extension. There’s still a lot of fingerprinting vectors though, so use Tor Browser or Mullvad Browser, ideally with JS disabled. This website is a great way to check your fingerprint: https://abrahamjuliot.github.io/creepjs/
Browsers aren’t just apps, they’re effectively platforms which run all kinds of apps you end up accessing online when you visit sites. Since the browser leaks the id to these apps, you’re effectively trusting the apps. Sure, you could run your browser in a VM or whatever, but that’s missing the point entirely. The real question is why your machine needs to have a unique identifier, and why the fuck it’s baked into functionality of systemd which is now replacing the traditional tool chain with a monolith.
And yes, I’m fully aware of other metadata that the browser leaks, and the fact that people are just starting to talk about that is also a problem. Running with Js disabled or putting a browser in a VM, is not really a solution for vast majority of people. The issue is that we have systems that are designed to enable tracking by default, and you have to jump through hoops to get around that. Telling people here are the hoops isn’t really helpful.
I’m not familiar with the purposes or history of machine-id, I’d guess that it’s just a legacy artifact that can’t be easily removed now.
There’s definitely a lot to be desired when it comes to privacy on Linux. Unfortunately Linux was designed before many of the privacy and security best practices became established, which is why is it less secure than modern systems like Android (source). Trying to re-architect Linux at this point would be an insane undertaking. Machine-id is just one thing in a long list that would need to be changed. Nothing wrong with advocating for it, but I just wouldn’t expect it to happen for at least 5 years.
Containers are a modern technology with isolation and security as a core goal from the start. And by now, containers are already deeply integrated into the Linux community, for example look at how the entire Fedora Atomic project (including Bluefin, Aurora, Bazzite) uses container-based infrastructure to build the OS images. So that’s why I’ve been moving towards it as a solution for my privacy needs, and I recommend others look into it as well.
Edit: rewording some sentences
Systemd was designed long after a lot of these security practices and problems with tracking were well understood. There’s very little excuse for it doing a lot of the things it does. Systemd is literally re-architecting how Linux was meant to work originally, and for the worse. I get the impression you’re not actually familiar with the history of Linux or Unix philosophy in general.
Having to put everything into containers is really just a work around bad architecture that keeps being pushed in the Linux world. Containers are useful, and probably the only way to actually keep apps from having too much access to the system at this point, but I don’t see why bad architecture should be accepted and then have to be worked around.
I get the impression you’re not actually familiar with the history of Linux or Unix philosophy in general.
I’ve read enough mailing lists and issue trackers to know that they are far more complex than they look on the surface, so I definitely won’t claim authority about them.
Take this one that I found recently: https://bugzilla.mozilla.org/show_bug.cgi?id=1618257
It’s a bug report about Firefox’s favicon cache. They started looking into it, but found out that if they fix this bug, it creates fingerprinting risk, so they have to address that as well. And so the issue gets stuck in limbo for like 10 years, and is still open till today.
Regarding systemd, it had to be built on top of the existing architecture, and more importantly, had to appeal to the Linux community to be adopted, so it couldn’t change too much. I assume they have their reasons for depending on machine-id. It might not even be a direct dependency. Maybe it allowed easier adoption by the big players.
I don’t know, and honestly, I don’t really care about digging into every single fingerprinting vector (of which there are probably tons more), when I can just use containers. And while using containers might feel like a hack or workaround, if we look at Flatpak, it seems like containers are becoming the framework for app isolation on Linux, similar to what already exists on Android. So it may very well become the official solution to privacy and security on Linux.
My point is that systemd did not have to be built at all. It’s an abomination that goes directly against the original philosophy of Linux creating a monolithic monstrosity to replace individual and composable programs that used to be the way init works. Now, everything is tied to it and it’s become like a cancer in a linux system that’s inoperable. The whole system-id problem is just one example of why this is a terrible design.
is this something sites can actually query on linux system in most browsers?
for example, if cloudflare is checking if I am a human, are they able to read my machine id if i am using firefox, librewolf, mullvad browser, tor browser, chrome, or chromium?
yup, both Chrome and Firefox expose your machine-id by default
how did you learn about this?
i thought i was aware of privacy but have not heard about this before.
why are open-source operating systems allowing this as a tracking vector?
what is the smart way to reduce tracking by this mechanism?
