PC Operating Systems

Worth Mentioning

• OpenBSD BSD - A project that produces a free, multi-platform 4.4BSD-based UNIX-like operating system. Emphasizes portability, standardization, correctness, proactive security and integrated cryptography.
• Arch Linux GNU/Linux contrib - A simple, lightweight Linux distribution. It is composed predominantly of free and open-source software, and supports community involvement. Parabola is a completely open source version of Arch Linux.
• Trisquel GNU/Linux - Derived from Ubuntu, this project aims for a fully free software system without proprietary software or firmware and uses Linux-libre, a version of the Linux kernel with the non-free code (binary blobs) removed.
• Whonix GNU/Linux - A Debian-based security-focused Linux distribution. It aims to provide privacy, security and anonymity on the internet. The operating system consists of two virtual machines, a "Workstation" and a Tor "Gateway". All communication are forced through the Tor network to accomplish this.

Warning

• Don't use Windows 10 - It's a privacy nightmare

Remember to check CPU vulnerability mitigations

This also affects Windows 10, but it doesn't expose this information or mitigation instructions as easily. MacOS users check How to enable full mitigation for Microarchitectural Data Sampling (MDS) vulnerabilities on Apple Support.

When running a recent enough Linux kernel, you can check the CPU vulnerabilities it detects by tail -n +1 /sys/devices/system/cpu/vulnerabilities/*. By using tail -n +1 instead of cat, the file names are also visible.

In case you have an Intel CPU, you may notice "SMT vulnerable" display after running the tail command. To mitigate this, disable hyper-threading from the UEFI/BIOS. You can also take the following mitigation steps below if your system/distribution uses GRUB and supports /etc/default/grub.d/:

1. sudo mkdir /etc/default/grub.d/ to create a directory for additional grub configuration
2. echo GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT l1tf=full,force mds=full,nosmt mitigations=auto,nosmt nosmt=force" | sudo tee /etc/default/grub.d/mitigations.cfg to create a new grub config file source with the echoed content
3. sudo grub-mkconfig -o /boot/grub/grub.cfg to generate a new grub config file including these new kernel boot flags
4. sudo reboot to reboot
5. after the reboot, check tail -n +1 /sys/devices/system/cpu/vulnerabilities/* again to see that everything referring to SMT now says "SMT disabled."

Further reading

• CPU.fail
• Hardware vulnerabilities index on The Linux kernel user's and administrator's guide
• How to install/update CPU microcode firmware on Linux - Regardless of your CPU manufacturer, you should always install the latest microcode packages available to be protected from CPU vulnerabilities, especially if the command above reports no microcode in its output.
• MDS - Microarchitectural Data Sampling on The Linux kernel user's and administrator's guide
• RIDL and Fallout: MDS attacks on mdsattacks.com
• Simultaneous multithreading on Wikipedia