Linux Hardening Guide | Madaidan's Insecurities
madaidans-insecurities.github.io

Writeup from 2022 that I assume is mostly still valid. TLDR:

  1. Mainstream Linux is less secure than macOS, Windows, and ChromeOS. (Elsewhere: “[iOS/Android] were designed with security as a foundational component. They were built with sandboxing, verified boot, modern exploit mitigations and more from the start. As such, they are far more locked down than other platforms and significantly more resistant to attacks.”)
  2. Move as much activity outside the core maximum privilege OS as possible.
  3. OP doesn’t mention immutable OS, but I assume they help a lot.
  4. Create a threat model and use it to guide your time and money investments in secure computing.

Once you have hardened the system as much as you can, you should follow good privacy and security practices:

  1. Disable or remove things you don’t need to minimise attack surface.
  2. Stay updated. Configure a cron job or init script to update your system daily.
  3. Don’t leak any information about you or your system, no matter how minor it may seem.
  4. Follow general security and privacy advice.
  • monovergent@lemmy.ml
    5·
    4 hours ago

    As someone who did use this guide as an exercise in making my setup as secure as it could be without changing distros or hampering productivity, a few words of advice:

    • Make a threat model for yourself before diving in and apply the mitigations judiciously. It’s not exactly a checklist, just use something secureblue or Qubes if you are really paranoid about your computer.
    • The majority of the mitigations ‘just work’ and have no noticeable impact on performance, battery life, or compatibility.
    • If your CPU/Memory performance widget breaks, dial back on the ptrace options
    • If Flatpaks fail to launch, dial back on the namespace options
    • Check back every so often because some of the options end up having unwanted side-effects with updates. See the preamble in boot parameters, where a change in Linux made in 2021 (which finally made it into Debian Stable this year) made the slub_debug mitigation actually worsen security.