Hello, and welcome to this Pluralsight course, CompTIA Linux+: Security.
My name is Andrew Mallett, and I'm going to be your instructor for this course.
And in this module,
we're going to be guiding you through the overall example of
what we mean by securing Linux systems.
Securing your IT systems and infrastructure has never been so critical.
To meet both security and compliance targets, you must know how to secure Linux.
So come on then.
Let's go through and learn a little bit about these
exciting topics that we're going to discover.
Working with Pluralsight and CompTIA certification,
we'll help you learn and secure your Linux systems.
During this course,
we're going to be taking a look at file permissions and access control lists.
We'll be taking a look at mandatory access control
lists such as SELinux and AppArmor.
We're going to be taking a look at how we can secure our SSH systems,
gaining secure remote access through to Linux,
and we're also going to be taking a look at how we can use identity
management systems and manage our user accounts,
group accounts, privileges, and privilege elevation.
Having managed this,
we take a look a little bit more at SSL and TLS and how we
manage our public key infrastructure.
With all of this done and dusted,
we move on to looking at host‑based firewalls to secure our systems.
Working through with CompTIA,
who are very adamant that you should be learning Linux,
not a particular Linux distribution,
we make sure you have exposure to a range of different Linux systems.
Working with AlmaLinux 8.5, which is a RHEL rebuild,
Ubuntu 20.04, and openSUSE Leap 15.2,
you're going to be able to gain a wide range of experience.
We build these inside of Vagrant and VirtualBox,
which does mean if you're using something similar,
you can download the Vagrantfile to build these
machines simply in your own environment.
Now the first thing that we're going to take a look at is whether or not you
should just accept the defaults having installed some software,
and you can probably guess from the way that I'm
saying this that the answer is no.
The defaults might work for you,
but you're certainly going to have to investigate what the defaults are.
So just as an example,
if we're working on our AlmaLinux system and decide
to install the HTTPD web service, the file permissions might not be the best.
So once we've installed it,
we can go ahead and take a look at the file system permissions.
Now we won't be managing our file system permissions in this instance,
but we certainly do want to go through and take a
look at what the permissions are.
And we're going to see that the permissions rely on our web server,
gaining access through to the directory and the underlying
web pages through the others account, so being world‑readable.
Now that certainly isn't correct,
but it happens to be the default on pretty much most Linux distributions,
including the enterprise distributions that we are working with.
The whole idea is that we gain the understanding of what
the defaults are and decide whether or not they're going to
be suitable for our scenario.
And I'm guessing a lot of the time they won't,
and that's what we want to be able to highlight to you,
the importance of investigating the underlying permissions.
It doesn't matter if it's file permissions that we're
looking at or other types of security, never just blindly accept the defaults.
Learn what the defaults are and secure if necessary. Now I think it's time we found ourselves a command line.