Linux security : The user and superuser concept and how and why it keeps your computer secure

Security is an important but complex topic.

So I’ll be doing a series of articles, focusing on the principles and working of security of Linux.

The challenge is that it’s an ever-changing idea. Software we think of as secure can become insecure as hackers figure out how to break though whatever safeguards were once coded in.

For users, it means being vigilant—staying on top of your system and considering security a recurring task rather than something you do once and can then be considered finished. In this article, I’m going to run through the best practices for keeping your system secure. I’m not a hacker or a security expert so I’m not going to get very detailed. Instead, I’m going to explain some basic, fundamental, and essential security concepts and give you a few manageable things to do to keep your computer secure. In this series of articles, we’re going to discuss:

■ The user and superuser concept and how and why it keeps your computer secure

■ Linux viruses (and anti-viruses)

■ Linux firewalls

■ Privacy on Linux

■ Best practices in running commands safely

■ Hardening Linux:OS Hardening Principles

Security issues can send personal information, like logins and passwords, to malicious third parties. These issues can also give these same bad people access to all of your personal files.
Think of security bugs as a hole in your home. With the hole there, things, like burglars, can get into your home. And think of security updates as patches for the holes. With the holes covered, it’s much tougher for someone to get in. Now let’s talk about other ways to keep your system secure. Let’s start with the Linux user and superuser concepts. This idea is the key to keeping Linux systems safe.

Users and superusers in Linux

If you think about it, security is about preventing someone from doing something without your permission. In real life, it could be someone stealing something from you, which by definition happens without your permission. With your computer, it could be someone stealing data from you, again, without your permission.

Superusers are users with certain privileges on a system. These privileges are permissions. Superusers have permission to do certain things on a system, like install software, configure internet access, and even print. That’s why you need to enter your password before you add or remove software.

Because you don’t want just anyone installing software on your system. Otherwise, they could install something mean and nasty. Linux has a list of users who can perform certain tasks and if you’re not on the list, you can’t do those tasks—like installing or removing software. Malicious programs work by installing something without your consent. These malicious programs can then do anything from destroying your data to sending out all of your private data, including valuable pieces, like passwords.

The Linux permissions concept makes it hard for someone to install something without your consent. Linux has a bunch of user groups with certain permissions, or access rights, based upon the user group to which they’re assigned. This is helpful on systems with more than one user, like if you share your laptop with someone (or a group of people). Every person can have their own set of permissions, which prevents an unauthorized or unknowledgeable person from doing something that might harm the computer.

Let’s pretend you’re going to share your computer with someone who doesn’t know much about Linux. You’re going to want to make a new user with restricted permissions. Let’s do that so you can see what that process looks like, and so you can get a sense of how these permissions keep your computer safe.