Linux is not a secure operating system. However, there are steps you can take to improve it. This guide aims to explain how to harden Linux as much as possible for security and privacy. This guide attempts to be distribution-agnostic and is not tied to any specific one.
DISCLAIMER: Do not attempt to apply anything in this article if you do not know exactly what you are doing. This guide is focused purely on security and privacy, not performance, usability, or anything else.
All commands listed in this guide will require root privileges. Words beginning with “$” sign indicate a variable that may differ between users as to suit their setup.
https://madaidans-insecurities.github.io/guides/linux-hardening.html