File Access and Permission Control in PCs (Linux, Windows and Mac)

Dear all,

I am just a bit flabbergasted by the file access and permission control measures in PCs. According to my personal experience and research, if ‘user1’ (non sudo / admin) installed the XYZ application, then the application can read everything ‘user1’ can read. For example, everything under 'user1’s home file, say downloads, documents, pictures, videos and even hidden files like .config, etc, var. Well bascially everything. I think flatpaks, snaps and firejail can kind of mitigate this risk, but some applicatoins dont offer flatpaks or snaps, while firejail may require some technical skills to use. In addition, Librewolf advice aganist using its flatpak version because it “prevents the browser from using its usual sandbox for process isolation.” Source.

In addition, there is very limited permission control in Ubuntu (not sure if it is also a Linux thing, maybe fedora or arch is better?). Any apps can access microphone and camera, unlike Android or iOS.

In general, i am just shocked by the lack of access control by default in PCs / Linux.

Thank you for reading this. Any replies will be greatly appreciated.

That is correct. Applications installed on desktop operating systems can see everything in the user profile. macOS does much better at mitigating this by requiring all apps in the Mac App Store to be sandboxed (since June 1, 2012). Apps outside that don’t need to be sandboxed but Apple does have their Transparency, Consent and Control (TCC) security feature that mitigates apps from accessing parts of the device without user approval anyway. However, that has been bypassed pretty easily before. Linux is even worse than Windows when it comes to sandboxing and exploit mitigations. iOS and Android are the most secure as they were made from the ground up to be sandboxed and implement exploit mitigations better compared to their 20th century desktop counterparts. Security for desktop operating system were an afterthought.

This is why iOS and Android are more secure, harder to exploit and why their zero-day exploits cost a lot of money. You have to chain multiple exploits to escalate privileges on those devices. It’s also why ransomware doesn’t work on mobile devices. The only thing they could encrypt is itself and any files it makes, it cannot encrypt another app or other files.

Matthew Green answered a question someone had about whether the Signal desktop client (though it can be any other app like WhatsApp) was as secure as the Signal mobile app. The answer is ‘no’ precisely because of this. iOS and Android are the most secure devices available. It’s why I recommend people do as much stuff as they can on their phone over using a computer. macOS and Windows are improving their security; Linux, however, isn’t doing too good.

Hi there, I hope you are doing well.

I understand your concern about Linux’s lack of strong default access controls, which can expose personal data. While solutions like Flatpaks and Firejail help, they aren’t always available or easy to set up.|

Mike Taku.