I have all these links for you below and these are some really good resources to take a look at when
we're assessing the actual Linux kernel of a target or potential target within our pen test.
See, kernel.org is a place you can go to to get a good release or more current release
of the actual Linux kernel itself. Maybe not Ubuntu per se, but let's say you just want to
deal with the actual internal bolts and nuts of the actual operating system itself.
Well, as you can see here as I zoom in for us, that we have different versions
of a Linux kernel that has been maintained by kernel.org.
And right now they're all the way up to 6.18 RC5, stable being 6.17.7. Wait a minute,
you may have remembered in our previous video that our Linux kernel is 6.14.
Now, why is that? Well, that's because that's what Ubuntu is more stable at right now.
And when we run our sudo apt update and upgrade, there's no kernel updates through Ubuntu.
So what we're taking a look at here is a discrepancy and we'll see why this matters.
Because once we go and do a search for CVE records and all I did here was search for
the version number, so 6.14.0.33, I got this as one of the CVEs that came up.
And you can see here that it does affect Linux. And if I scroll down a little bit more,
you can even see that it affects versioning numbers.
And since we have 6.14, this particular one is unaffected through 6.12.57 through 6.12,
whatever, but it does pop up because it is not within that number of unaffected.
But we can do a simple search on the actual NIST site for nvd.nist.org
and see that we have CVEs that come up as well that affect that particular versioning number of
Linux kernel. And I'll go more into what this is in just a second. I just wanted to show you
that down at the bottom, you see known affected software configurations. And we see right here
that we also get that from this number to this number, including or excluding or whatever the
case may be. And this particular one, CVE that we're looking at on NIST does have us included
in it. So just looking at the base numbers themselves. So if we scroll to the top,
what is this? Well, this is CVE-2025-23143. And this is where the Linux kernel has a vulnerability
involving some commands dealing with the actual site connections and specifically going into
mount. And right here, it even gives you step-by-step on reproduction of the actual error
itself. And one of this key points is that it involves a mount using CIFS. So basically the
vulnerability is the kernel version of the operating system has a vulnerability where it has
that comes up during a connection to a Windows system. Ironic, right? Now, the information that
we gain from a scan, our vulnerability assessment, and also using other things like Nmap and whatever
the case may be to identify the operating system versioning allows us to be able to go through and
identify potential vulnerabilities within that particular kernel versioning or different pieces
of software on that system. If you remember in Windows 10, we do have BWAMP installed,
which requires us to use PHP 7. And there are multiple vulnerabilities would be PHP 7. Well,
the same is for Apache, which is installed on Ubuntu due to previous skills. And there are
also vulnerabilities within the kernel itself. So it's basically taking all of that knowledge and
doing a little bit of reconnaissance and open source intelligence gathering to make sure that
we can pull in what vulnerabilities are being reported, what do we know about, and how can
we potentially exploit them through the use of things like CVE research? Now, this ties into
other known vulnerabilities and other weak areas within the POSIX-based operating system world.
But this is just one area that I really want you to pay particular attention to because to wrap
this particular portion up, I leave you with this. And this is probably the most important out of
this. Just because you download an operating system like Ubuntu from Ubuntu's website does
not mean that that's the actual operating system itself. That sits on top of a kernel, the Linux
core foundation of the true operating system itself. Ubuntu is nothing more than just a flavor
put on top of that Linux kernel to give it that fizz of uniqueness. And the vulnerabilities within
the operating system itself exist within that kernel. And that's something that's often overlooked
because when folks commonly look at operating system vulnerabilities, they look at it as an
Ubuntu system and not a Linux system with a Linux kernel.