OccupyTheWeb you've said this multiple times
and it's the reason I think that you wrote this book Linux is one of those skills that you
have to have right? Yeah Linux is one of those fundamental skills that every hacker has to have
I also open up the book with the the first line of the book is hacking is the most important skill
set of the 21st century. Hacking is playing a key role in geopolitical events, it's playing roles in
espionage, it's playing roles in Criminal activity all of these things are part of hacking. Now this
is the kind of stuff I love to see, I mean what a beautiful view but not only that I love it when
companies help people change their lives through free education and lowcost certification programs
and I really want to thank Juniper for doing this they are providing a whole bunch of training
for free security training, networking training, DevOps training. You can use my link below
https://juniper.net/davidbombal sign up and get access to their training for free but not
only that if you go through their assessments you can get your exam for a discounted price at the
Associate level as an example you can get an exam for $50 big shout out to Juniper for supporting
the community by providing free training and lowcost certifications that help people change
their lives so go and sign up for their free training get certified and change your life. Hey
everyone it's David Bombal back with OccupyTheWeb, OccupyTheWeb welcome. Thanks David it's always
an honor to be back on the best IT cyber security Channel on YouTube. I appreciate it and just
for everyone who's watching we've done a whole bunch of videos we were just talking offline
about the Mr Robot series that OccupyTheWeb has done with me. OccupyTheWeb that's one of your
favorite series right? Oh it's definitely one of my favorite TV shows and if you talk about
Hollywood's depiction of hackers it's probably the most accurate Hollywood does not have a good
record in terms of being able to to depict hackers as they really are and in that show what most of
us love about that show is that it's real hacking it's you Mr Robot Elliott in the show you know
he's he's a real hacker he's doing real hacking with real tools from Kali and other places so
that's why we love it. So I'll link that below for anyone who wants to watch those but before we
get started with today's video I want to mention your books once again and I'm really excited
about today's video because we're going to be talking about Linux basics for hackers um
but OccupyTheWeb also has Network Basics for Hackers as well as Getting Started Becoming a
Master Hacker and I always say this and again I I'll mention it a million times I really like the
way that you write your books you write it from a hacker's perspective with a hacker's mindset and
with my background in networking it's really nice to see your take on networking but OccupyTheWeb
you've said this multiple times and it's the reason I think that you wrote this book Linux is
one of those skills that you have to have right? Yeah Linux is one of those fundamental skills
that every hacker has to have the book grew out of my experience of training hackers for the US
Military and the intelligence community and when I used to do that and this is quite a few years
now it's at least 10 years ago now I used to get a room full of very talented people who wanted to be
trained in hacking and a good number of them have never used Linux before and so I couldn't really
train them without taking some time to be able to train them on Linux first and so I developed a
little handbook for them and we'd spend the first day or so going through Linux Basics so that
they could go on to the more advanced stuff and then that grew into a book and when I when I
first developed the handbook for the military it was very small and so one of our goals with Linux
Basics for Hackers was to keep it small you know matter of fact I told the publisher I wanted it
to be less than 250 pages and we did that it's pretty small it's succinct it's concise it covers
the what you need to know to get started you know we don't put a lot of depth and a lot of detail
because you know there's a lot of books out there you know that are are great books that cover Linux
in great depth and detail but nobody reads those books exactly exactly so I wanted a book that was
accessible that people would actually read from cover to cover and that's what has happened it's
become the bestselling Linux book in the last 5 years and so it continues to sell extraordinarily
well 5 years later and so that's why the book was was written, was to get people started to
get them into Linux because so often we'd be training people who had only spent their life in
a macOS or a Windows environment and just weren't familiar with the command line in Linux so this
is what the book is designed for of course I also open up the book with the the first line of the
book is Hacking is the most important skill set of the 21st century and I will reemphasize that
hacking is the most important skill set of the 21st century if you look at you know what's going
on in the world today it's once again played out that hacking is playing a key role in geopolitical
events, it's playing roles in espionage, it's playing roles in criminal activity all of
these things are part of hacking I'm not saying all of it's necessarily good what I'm saying
it's the most important skill set of the 21st century. So if you want to play a role in the most
important skill set you know this is the place to start is Linux Basics for Hackers, get your Linux
skills down first and then you can move on to the more interesting and more advanced material but
you got to have those Linux skills first. I think I see it a lot and I'm, you deal with a lot of
beginners I'm I'm assuming you see it all the time they want to run before they can even crawl
right?Exactly and once again I've seen this for for many many years and that's that was the whole
purpose of the book is to get you to get you up and running so that you can go and do whatever
you're going to do with hacking but if you don't have the Linux skills you're really you know
you're putting the you know the old saying the the cart before the horse you got to have the Linux
skills, you got to have the networking skills, those are two fundamentals you have to have to be
able to function in this world. Why why use Linux um I I mean then there's there's you've given us
a good reason to write the book but why why is Linux so important?Well Linux is is different
than the other Operating Systems in that it's basically it's all open, it's open source, it's
open you can see all the source code and that is why people have developed their tools for Linux
I mean there are tools that are developed for Windows and there's some for mac and there's
some for Unix but most probably 90 to 95% of the hacking tools are developed for Linux why
Linux because it's open source the people who are developing the tools can see the source code
and use it. Linux is open source it's transparent it allows you to have granular control over the
system things that you're not going to see in a macOS or a Windows system and and probably the
best reason for a beginner outside of these kind of esoteric reasons is that most of the tools are
written for Linux right I mean they're they're almost almost all written for Linux almost all
so if you don't know Linux you're going to miss out you you're just simply not going to have the
capability that you're going to you know get here if you're trying to do it in a Windows environment
and one of my criticisms of say for instance the certified ethical hacker certification is that
they don't emphasize Linux they they're trying to teach hacking from a Windows perspective and
they don't require that you know Linux and that is a disservice to anybody who's trying to achieve
that certification because if you don't know Linux you're not a hacker. Let's let's be really clear
okay if you don't if you don't know Linux you're not a hacker you might call yourself a hacker, you
might call yourself a certified ethical hacker, you might call yourself anything a pentester
but if you don't know Linux you're not really a hacker. I love that I think you've just
summarized it right there. The first intro, the introduction of Linux basics for hackers
we talk about how to go ahead and download and install Kali Linux but David's done some great
videos on how to do that so we're not going to replicate that and David you can give them links
to how to to your videos and you've got some great videos to do that so we're not going to waste
your time folks on doing that you can go to David's excellent videos on how to go ahead
and download install it either as a physical on a physical machine or a virtual machine. I use
Virtual machines. Why do I use Virtual machines? Well there's there's a lot of advantages of
using virtual machines but one of the things that those people are in my classes know is that
I use multiple virtual machines so I I'll have different virtual machines for different Operating
Systems so I can switch between them. I can also use my virtual machines as as target an attacker
without having to go outside of my own system, so there's a lot of good reasons to use Virtual
machines you can see the upper tab here I've got a Ubuntu over here I've got a bunch of other systems
on here I got multiple versions of Kali because you know there's some Kali different versions of
Kali do things better than others so I'm running virtual machines all the time there are some areas
where virtual machines don't work work as well as a physical machine and one of those areas is
Radio hacking you know the SDR for hackers there's there's really some difficulty with being able to
maintain that SDR Hardware to a virtual machine it works but not real well and so there's one of the
there's one of the drawbacks outside of that in a few other places virtual machines are terrific for
a learning environment and teaching environment. So OccupyTheWeb 2 questions would would you
recommend for beginners start with virtual machines and do I need to have the latest version
of Kali Linux or is like an older version okay? Well one I recommend virtual machines, virtual
machines are great so you need to have a little bit of knowledge of virtual machines to be able to
function well for as as a a beginner, a learner, you can maintain a closed environment where you're
both the attacker and the target and you don't have to worry about any legal issues of going out
there and attacking targets that you you shouldn't be on or illegal for you to to target so that's
one of the reasons. Two is I can maintain many Operating Systems on my single system. If you're
going to maintain multiple Operating Systems the more RAM that you have in your system the better
it's going to run for you and then you know there's a lot of beginners who want to use the
latest and greatest and I just got done teaching a class and one of the things that happened in this
class last week is that I'm running a year old version of Kali and the things that we were doing
actually worked better in this older version than work in everybody in the class who had the newer
version so they had to actually downgrade their systems to be able to do what we were doing in
class, so don't be fooled by you know the latest Kali or the latest for that matter Windows or
whatever you is that sometimes the older things if they work there's no reason necessarily
to upgrade them other than maybe for security purposes right but I I maintain versions of Kali
going all the way back to the backtrack days. So way back when you many viewers may not know this
but it used to be called BackTrack and so I've got versions of BackTrack going back to BackTrack
1 and I've got BackTrack 2 back BackTrack 3, BackTrack 4 and then I think I think at BackTrack
4 it switched over to Kali and that was somewhere around 2012 I think or 2013 somewhere in that
area and so some of these older systems actually do what I want better than the newer systems do
so as a result I have images of all of these old Operating Systems around and sometimes I have to
go back to them but when I have a Kali that does what I want why would I go and get the newest one
I have to have I have to have a reason not just because it's newer I have to have a reason to go
and and go to the latest and greatest so as you'll see in this particular video here I'm using 20223
why well because it does what I want and some of the changes that have taken place since then I
don't necessarily aren't necessarily good for what I do. But from a Linux point of you it doesn't
matter right because like the commands have been around forever? Yeah the the the core, the
kernel of Linux has been around since what 1993, 92 it's when Linus Torvalds first released it and
and most of the commands are the same so the the fundamentals of Linux whether you're talking
about Kali, Arch, Ubuntu, Parrot, Red Hat you know you go through all the distributions the
primary commands are all going to be the same in all of these Operating Systems so it doesn't
really matter what version using you could really do what you want to do in terms of hacking from
an Ubuntu, okay from Red Hat, these these are fine to use the only real strength of Kali is that
one it's Debian okay so and Debian handles many of the tools better Debian is a distribution of Linux
so Kali is built on Debian and so is Ubuntu but they kind of they Fork from Debian in different
some different ways but you could use Ubuntu, you could use Lubuntu, you could use Red Hat, you
could use any of them so when people often ask me you know which is the best Linux distribution the
answer is they're all good and so the strength of Kali is that it's built on Debian which works
oftentimes a little bit better on some of the tools and it has all the tools built into it
and Parrot, Parrot has the tools built into it as well Black Arch has the tools in general
you can move the tools from any of the Linux distributions. You can run them on basically any
of the Linux distributions so that's not really that big of an issue it's more of a convenience
issue rather than a functionality right. So one of the things that people who aren't from the
Linux environment or Unix environment there's a few terms and few ideas that are kind of important
to introduce here. One is the term that people in Linux always talk about binaries right these are
basically what people in other environments like Windows would call an executable these are files
that can be run and these include simple things like you know the PS command, the cat command,
the ls command, the CD command those are all binaries as well as some of the tools that we use
for hacking those are binaries so when you hear that term don't don't get upset you know that's
it just means that it's like an executable it's a file that can be run. The second concept that's
really important in getting accustomed to Linux is that Linux is case sensitive that means that
a uppercase c and a lowercase C are two different things right so that if for instance there's if
you type desktop with lower case letters that's different than uppercase letters. So for instance
let's say take a look at our our Kali here, we can go to there is a directory called desktop
and if I go ahead and go cd desktop right like this it's going to come back and say there's no
such directory file or directory, why because I didn't start it with an uppercase D so if I go
and do it like this right which is the way it's actually supposed to be you can see it goes to
desktop so if you get this message right here no such file or directory one of the first things
that you want to do is check to make sure that your case is correct this case I would you know
if I was a beginner I might look at that and go my God I know that there's a desktop right there's
got to be a desktop on this system what's wrong with my Linux and and really all it was is that
you didn't start it with a didn't start it with a uppercase D so that applies to almost everything
in Linux that it's case sensitive. Windows is not case sensitive so this is going to take a little
bit of getting accustom to. A directory is the same thing as what some other Operating Systems
might call a folder so it's a directory it means this is where I'm storing all of my files at right
you know one of the things that's also kind of important okay to think about in Linux is that it
has a file system that's a little different. Let's take a look at that I'm going to put up a diagram
here of the Linux file system for those people who uh are coming from a Windows environment or
others this might be new information. So in a Windows environment at a very top you might
have a c or a d or an e or an f there might be these are physical drives Linux works on a
logical file system and at the very top there's a slash and that slash flash is often referred
to as the root file system that's the top of the file system underneath the root you have a number
of subdirectories and probably the most important ones is there's one here called root and that's
the root users. Okay root user is like the system admin in Linux. We have the boot the etc, etc
is generally where your configuration files are stored now we say configuration files those people
are coming from a Windows environment when you configure an application you usually have to go
through a series of clicks and click click click click click click click click so so configure it
in Linux configuration is all done through text files so there's a text file you go in, you
open up the text file, you make the changes, you save it and then you restart the service
and then you've reconfigured it. Those files are generally in the etc directory generally. There's
a home and that's where you as a user are at all right so for instance I go back here, to go back
a level in Linux I go cd .. that takes me back one level I can go pwd present working directory
this tells me where I am in the file system this is a really useful command so if you're not used
to using the file system the the command line in the Linux file system you can always just enter
pwd and it'll tell you where you are and so you can see where I am I'm under home and then my
username and my username here happens to be kali it could be other things but that's where all
of my stuff is stored is in my home directory. Let's go back to our our diagram again then you
see there's the mnt directory okay this is where your outside so for instance if you're putting a
physical drive on your system so a new hard drive new SSD it's going to be mounted at this directory
that's where it's going to be attached to the file system and this actually is kind of a a term that
has it's a throwback to like the 70s and 80s when people used to physically mount they would take
a tape you know back then data was stored on tape and they would physically take a tape and they
would mount it unto a computer big a big tape and so that's where this term comes from because
remember that Linux is basically a clone of Unix, Unix dates back to the 70s and so some of the
terminology comes back from comes through that era. Process is proc is where we have a lot of
uh our processes we have files there that manage those I'm going to skip this one, we'll talk
about dev this is devices this means like things like keyboards and mice and all of the devices on
your system are maintained in a file here and then we have bin and sbin these are binaries that's
what term I was just talking about is binaries this is where you'll see stored the files that are
executable and sbin is system bi, system binaries and then you'll see here lib which is libraries
these are the what in the windows world is often referred to as a a DLL a Dynamic Link Library
this is just basically code that can be reused so if I'm writing a tool, writing an application,
I can go in there and pull and use call a piece of code in front of the libraries that I need to make
my application work so it's rather than everybody rewriting the the same code over and over again
like how do I, how do I make a window right you know in my application? I can just call the code
and this plays a big role in hacking because you often times need to have the proper libraries to
actually use the tool and so one of the things that you'll see as you develop as a hacker is
that certain tools you need to download specific Library files that the application is dependent
on and then finally we have usr and this is where we're going to see other users on the system are
going to be underneath this directory here. We can see these directories if we go back to go cd and
then go right to the very top of the file system right CD / that takes us you can see here it shows
me a slash that means that I'm at the very top of the file system now I can view what's in there by
simply using the LS which is short for list right list I can just go list and it'll show me those
are all of those directories and a few others that we didn't have on our diagram and one of
them that's important here is media so in that diagram I talked about mounting a hard drive to
the system but in modern Linux systems we now have what's called media where your flash drive and
other devices will attach or am mount to the bio system and we'll talk more about that in future
videos but they now get mounted at media and not at mnt and you see a few other things that are
there as well so this is one of the key commands is ls I like to use ls- l let's go and do ls- l
and it gives me a little different view of the same information so what it does now is it gives
me some information on the permissions all right these are the permissions we'll talk more about
permissions in a future video and then it tells me how many links it has that's what this is is links
and we'll talk more about links in the future one of the things that I didn't put in the uh my
Linux Basics for Hackers is much of a discussion of links and so that's probably something we we'll
talk about in the later class. This is the owner of the file or directory notice here this let's uh
let's talk about this very first letter here that tells us it's a link so this means that it's a
file that's linked to another file it's connected so that when I use when I click on or use that
particular command it takes me to another command that's what a link is it shows me right here that
the binary is also linked to user binary so when I use the binary file or directory it's going to
take me to the user binary. Binaries as I said are simply executable files. This first letter
here the D says that this is a directory when it starts with a dash like this one here that means
it's simply a file all right so you see oh most of these here are are all directories we might we
probably see some yeah right here we've got a file a swap file right there if it starts with a d it's
a directory, if it starts with a dash it's a file, if it starts with an l it's a link, and I'm going
to leave this right here which looks like gobbley, looks like gobbley goop to most people who
are new to Linux but basically what this is, is it defines who has permission to read write and
execute the directory or the file right. This is important in Linux security, so this is what our
top of our file system looks like right, we've introduced a few commands there a couple other
terms that I want to introduce here is the idea of a script and people you know hackers are always
talking about scripts right and usually usually hackers are using Python scripts. Right Python is
kind of the language of hacking tools now that's do it mean that all hacking tools are written in
Python right it means that a good number of them are and Python is native it's installed already on
your Linux all right so you don't have to install any interpreter for it but there's a lot of other
languages that are out there that are used for scripting of course there is what is referred
to as Bash scripting which is scripting within this shell environment we have this is this is
actually a shell or a terminal right that's what this is referring to here sometimes referred to as
a terminal emulator because back in the old days Linux was and Unix was run from a terminal where
all you you didn't actually have a computer all you had had was a a terminal that gave you access
to the computer so this is sometimes referred to as a terminal emulator or a shell and most of the
linuxes for that matter use a born again shell or bash shell the newer Linuxes the newer Kali's have
switched over to a different shell called Z shell and we can talk about that in a future video we
start talking about Bash scripting but there's other shells which is basically this environment
that we're working in here those are kind of some new maybe some new terms especially if you've
never worked from a command line obviously this is very similar to say a command shell or a uh a
PowerShell in Windows although I would say that it's superior to both. It's it's superior
to both of those right I mean PowerShell is Windows uh attempt Microsoft's attempt to give the
functionality of Linux into Windows that's the way I see it they brought in the PowerShell in recent
years because people were unhappy with the shell capabilities of Windows so give them some credit
but it's not as elegant I think it's actually kind of clunky relative to the the elegant shell
within the Linux environment but you know I'm I'm obviously have some bias here. I was talking to
someone has got many many years of experience in the cyber security industry and he works for Cisco
now he's like a big shot at Cisco and he said uh Powershell is the root of all evil because that's
how most attacks that's how a lot of attacks are made I shouldn't say all attacks but a lot of
attacks are done that way so you know just to hide on PowerShell even more sorry go on. Yeah I mean
that's a that's that's very true a lot of attacks use PowerShell especially post exploitation or
in once somebody's gotten inside the system they can use PowerShell to maintain and do all kinds
of nefarious things on the system to PowerShell but and also it should point out that a lot of the
commands that we we use in Linux have been aliased into PowerShell so if you're trying to use some
of these commands that we're talking about here you can use them in PowerShell all right they're
not native in PowerShell but they're alias which means that they're linked into uh PowerShell
so you can use your Linux commands within PowerShell. Let's a, that's here's a command
that's kind of important and that's called clear, so so so what we're going to do is we're
going to clear our screen gives me a and I'm still notice I'm still at my root directory, let's
go ahead and uh let's go ahead and navigate okay cd is change directory to starting at
the top route then going to home, then going to my user which is kali. Okay so that's so now
that I'm there of course I can I showed you that we can use the pwd to always know where I am,
right this tells me this tells me where I am, I'm at home Kali another really useful and simple
command that's always important to know is who am I? Now this isn't going to give you it's not
going to reveal your identity right? yeah we want to know we want you to run that come on. What
this is, it's going to tell you who are you logged in as? Why is this important well because in Linux
especially when you're talking about using Linux as a hacker there are certain things that can
only be done when you are root or root is the same as system admin it's the all powerful user now
people often will tell you that you probably don't want to run your system as root all the time why
because if you get hacked then the user the person who hacks you is going to have all the privileges
of root, which means they have all the privileges they can do anything they want just like the root
can. So Kali has taken that under advisement okay the people at offensive security and primarily
you're working as a regular user with limited privileges when you're in Kali today that wasn't
the case in the past and so for people like me it's taken me a little bit to get used to this but
in any case so I hit who am I you can see that I am kali that is my regular user who doesn't have
all the privileges if I want to run many tools okay within Kali I often have to precede that
command with sudo, sudo is and this is something that's not in Linux Basics for Hackers because
back then it wasn't required so this is something that's come about since the book has been written
I wrote the book in 2017 it got published in 2018 so right around soon after that uh the new Kali
started to require that you had to actually use sudo and sudo allows you to move into the root
user for a single command all right for a single command if your user has those permissions and
we'll get into that in a later video but there's a group of users who are on the sudoers list and
if you're on that list you can use sudo the way that Kali is set up if you come in as once you
if you create a user when you install it you're on that list so you can use sudo to switch to
the root user and run that and that'll give you all the power of the Operating System you you're
not going to be limited to anything at all that's a command that's really important in the newer
versions of Kali I showed you cd that's changed directory all right so that's an important one
so if I wanted to change a directory say to the etc directory remember this is where all of the
configuration files are at all right now I'm at etc and then I can go ls -l and I'll see all of
the various directories here's that sudoers that I was talking about okay the sudo config and
sudoers and we'll we'll talk more about that it's kind of more advanced stuff you can see also
here's snort some of the people who've read my book I I think it's in Chapter 2 or 3, we uh I use
snort as an example of a application that we can we can use I'm showing you how to use it to using
Linux in it and it doesn't come anymore with Kali so in a later video I'll show you how to install
it in Kali it's not that hard to do but I get a lot of questions about that because it's no longer
it's not installed by default and it's not in the repository anymore but as I'll show you in a later
class is that you can actually pull applications, binaries from any repos any Linux repository
so you don't you're not limited to the Kali repository if you know how to do that and I'll
show you how to do that. You can see I have it installed on my system if you don't know snort
snort is a IDS an Intrusion Detection System, it allows you to be a ble to detect malicious attacks
to your system you it's one of those things that you if you want to protect your network and
protect your system snort is designed to do that it's now owned by Cisco as of 2014 so it's almost
10 years now it started off as a small open- source project some 20 some years ago, it got
purchased by a company called Sourcefire and then Sourcefire got purchased by Cisco so it's part of
Cisco's product line because it started it as an open- source project it's still an open- source
project but they do have a version a commercial version as well you'll see this in a lot of open-
source projects that get purchased by commercial companies they still have an open source Community
version and then they have a a commercial version snort is one of those good examples of that.The
open source version still works great you know we can maybe that's something we'll do in a future
video as well but at least I'll I'll show you how to install it on your system and the future video
when we start talking about how to install new software into Linux and of course that's a real
key kind of of skill set in Linux is you know you you've got all these tools already built in
the Kali but you're invariably going to run into a situation where you need to install new tools
and I'll show you how to do that and I think it's adding new software chapter 4 so we'll do that on
chapter 4 how to add new software. So just just just I'm going to try and ask the the beginner
questions, so why did you use forward slash why not just cd etc? Okay so that's an important
question um so what happens is that when I when I change directories okay there's this concept
of absolute path and relative path within well for that matter in any Operating System it's
not just in in Linux it applies to Windows, it applies to Mac, applies to Unix, so what I'm
telling the system here is I'm coming in with an absolute path I'm saying change directories
starting at the top of the file system the slash that's the root and then move from there into etc
so it's let's go back to our diagram. All right, let's go this is our what I'm doing here is I'm
saying get right, go right here slash and slash is the top of the file system okay it actually
is it it denotes the top of the file system and then go to etc okay so if I were to have let's go
back let's go back one level it goes back to pwd, let's do that this is a real important concept
and let's go say cd to my home directory which is kali okay like that notice that I typed it out
with an absolute path starting with the Slash and then home and then kali. Now if I said cd etc this
is what's called a relative path all right, this is change directory to etc, this says go ahead and
look for the etc directory after the root the home the Kali so what we're looking for essentially is
root home Kali etc and when I do that right I get an error because there is no there is no directory
there, this is called relative path to a directory now if I go cd etc I say go ahead and start at the
very top and then move down to etc that is going to be the absolute path and that takes me there.
So the concept is you can write the absolute path starting with the very top of the file system
and then going through each directory structure absolute path relative path says start from where
I am right now and then look for a subdirectory that had that has this name so often times when
people start this is they get this kind of error message right here no file such file or directory
because they're not fully comprehending the the concept between absolute path and relative path
right so those are two important concepts and it's probably something that I I don't think I fully
developed in Linux Basics for Hackers so it's a good question and I I get a lot of questions like
that also when we're we're talking about doing an ls command and I told you using the ls -l this is
what I use and it gives me a lot more information than simply the ls command right. ls command just
shows me the files and directories doesn't give me all the information about you know who owns
it and who what permissions there are on it but there's another variation on ls that's important
and that's ls -la now the difference here is that the a will give me the hidden directories and
files often times you'll see files that are hidden and they won't show up with an ls but they
will show up with the ls -a I'm going to clear my screen again clear so I can get the get a big
picture here. Now let's talk about ways that I can get help in Linux you know as you're starting
off in Linux you're not going to know everything about everything not none of us do you can be
using Linux from day one 30 years ago and that's how old Linux is is now 30 years old and you're
not going to know everything and there's always new tools that are coming up and you're not going
to know how to use it and so one of the best ways of of finding information about whatever tool
you're trying to use is to simply use the help. One of the best tools for hacking probably the
original tool and best tools for hacking Wi-Fi is aircrack. aircrack is the the granddaddy of
hacking tools okay of Wi-fi hacking tools and there you see aircrack -ng, the ng stands for new
generation that means that distinguishes it from the old generation aircrack and we just do help
and notice that I get a very helpful screen that gives me all of the key information that I need
about this particular tool. Now one of the things that I want to point out is that first of all like
any other command line interface you can just up arrow if I push the up arrow look what happens
I go, it gives me the last command sometimes you want to you know you don't want to go ahead and
retype the same command over and over again just go up arrow and it'll go ahead and pull up some go
through it and you see all my old commands that's kind of an important thing. Also let's go back and
do up arrow okay let's go to our, well let's go to our aircrack once again this is our a aircrack is
the granddaddy got to spell it right and I'm going to I'm going to do something I'm going to use my
Tab Key you can use the Tab Key to autocomplete all right so if youve put in enough characters to
make it unique you can just go ahead and tab an auto complete all right apparently there's some
people who watch these videos who complain that I don't use the autocomplete. I'm glad you did
that because yeah that's quite it's hilarious when people say that. So autocomplete you use
that you can use the tab to auto complete so here we go here's aircrack notice that I used a
double dash, Okay this is kind of a it's kind of an important concept so that switches or options
in Linux there's usually two types, right there are switches that have a options or switches is
what they're called notice here that if there a single letter okay there's one dash if it's a
word it's double dash. Now this is something that is kind of a convention in Linux but and not
everybody abides by it but it's generally a rule that most people abide by, see here all these are
single options so it's a single dash whenever we use a word as an option we use double dashes
that's it's a general rule it's adhered to by maybe 80% of applications not by all of them and
you can see here that here's our help right here sometimes you can get to help by just using a -h
in this case it doesn't it tells me that help is actually at dash dash help different applications
will use different uh options for getting help sometimes you can get help with not even putting
in the help you can just put in the command right and I'm going to go ahead and do an auto complete
with a Tab Key and then you can see that I just typed in aircrack and I got the help screen. This
is often times with with tools you can just get the help screen by just simply entering the name
of the the tool the binary okay the application and it'll pull up all of the help screen for you
aircrack is an excellent tool it's been around for it's been around for a long time. Let's see the
very top here we can see it's been around since 2006 so aircrack is one of those tools that you
should be familiar with and if you're not familiar with it you know you can learn more about it by
simply going ahead and looking at the help screen I'm going to go and do a a clear to open up my
screen real estate um another one of those tools that we uh we probably should be familiar with
as a hacker when you're starting out as nmap, so nmap that uses a to get help like I said is
that in aircrack we can get help by simply going ahead and entering the command and and then dash
dash help -h doesn't work with an nmap h does work for help and so we get the whole nmap. nmap is a
port scanner it allows us to scan a target system to see what ports are open what services are
running on it this this is a way to get a picture of what the target looks like one of the things
that I emphasize to all my students is that you can't possibly be successful in hacking a system
if you don't know what the system is. You have to do proper reconnaissance on your target to be
able to be successful, you will not be successful if you don't do proper reconnaissance. One of
the first steps of doing proper reconnaissance is knowing what ports are open, what Operating
Systems are running, what services are running on that system. If you don't have the information
you're not going to be successful NMAP is one of those tools and maybe we can do something in the
future or you've got other videos on NMAP but what I wanted to simply show here is that one there's
different ways of getting the help screen and some cases it's going to be dash dash help, in some
cases it's going to be just h and then there's something called the Man pages that that's short
for manual that has nothing to do with any gender right it has to do with manual and you go man and
then you say nmap and it'll come up with a screen that's going to give you a help screen it's going
to give you a lot more information than the help. It's going to give you a lot of, you can just
simply hit the enter and go through this long description of this is NMAP and so if you've never
used NMAP and you want to learn about it here's a way to do it all right and it's going to tell
you all about how NMAP works and this is going to apply to most tools okay most of your binaries
so we then notice it says at the bottom here press h for help or q to quit. So let q to quit. I
going to say that it' be great if you can do NMAP as well it's always nice to get your perspective
so you know we can do it I see it's in your book right so we can always add it as as part of the
series. Yeah we can do NMAP, NMAP is a is a great tool and NMAP has gotten a lot more powerful in
recent years as has added more scripts that you can use so it's actually become it started off as
a simple tool that basically open ports and now it's become it's kind of a hacking framework now
it's probably overstating it but it's become much more powerful than it used to be. Then let's clear
my screen all right so anything I'm trying to find you information on I can just use the man command
to get to a manual sometimes when there's new scripts that come out most of the tools that come
out are are scripts they are written as oftentimes a Python script and generally the developers will
create a man page a manual page but not always but generally they will one of the next skills that
we want to to talk about is how do I find stuff there's so much stuff inside of my Linux how do
I go ahead and find things? And there's there's a number of tools that I can use to be able to find
stuff. The first place to start I think is using the keyword locate okay so locate locate will
basically go through the entire file system and look for this keyword that's going to I'm going
to enter next. So if I go aircrack like that it's going to find every reference and there's a lot so
it's going to find every place where aircrack is at. Now this is a lot of information and it might
be useful right especially if there's only one or two references but if there's a lot of them it
can be more information than you want and so oftentimes what we're looking for is a binary,
binary being the application right and so this is these are a lot of files in here that really I
don't really care about and so what what I really want is where's that command at that I want to run
right and I can just do whereis right that those two should be pretty easy to remember locate
whereis and then I go air and then I hit the tab and I autocomplete and then it tells me
where aircrack is. The the binaries and this is the first one okay usr bin okay that's the users
binary aircrack. Okay user include aircrack and user share and this is the man page you can see
that we just looked at that this is the man page for aircrack and so that's really useful in being
able to find where the binary is. Now there's one other way that a couple ways I want to show and
that is that sometimes there's a thing in in there's a thing there's a there's a feature in in
Linux there's a feature in Linux it also applies to the Windows machines and the Mac machines and
it's called the path okay and and most people in using Windows system or Mac system don't ever
pay attention to the path but we often have to pay attention to the path in Linux because it
determines where the system is going to look for your command okay where is it going going
to look for your command and that's determined by the path variable. So if I go echo okay and
echo's another one of those those commands that basically says go ahead and show me display for
me the contents of a variable it's in my system we'll talk about environmental variables in a
later class. This is the this is the path is an environmental variable that stores where the
system is going to look look for my commands automatically it's not going to look in every
directory because that wouldn't be that wouldn't be efficient what it's going to look for it's
going to look for say the command aircrack in one of those directories that has binaries why
would it look in the etc directory or the dev directory because there's no binaries there right
so this is where the system determines where it's going to look for those and this is our path.
So the path variable says is okay when I type something like aircrack right just type it as a
a command it's going to look in user local bin, user local in this case sbin user local
bin user local sbin, user local bin, these are all the places it's going to look
and if it doesn't find it there it's going to come back with a message that says there's no
such file or directory that doesn't mean that it's not there it simply means that it's not in
one of these places and this come this can be really confusing for a beginner okay. I install
a new tool right and I try to use it I just type the command but that tools binary is not in one
of these directories. So if I'm looking for for instance where the binary is in a path directory
I know this gets a little confusing I can use the which command and I'm going to and I'm going to
do a tab and autocomplete and so what I did is I used the command which now this is different than
whereis, whereis tells me where aircrack binary is located okay it shows me all the places which
shows me where aircrack binary is located among the directories in the path variable slightly
different slightly different either one of these are can be really useful in being able to find a
binary if I've installed a new tool the binary may not be in the path so this is where I would look
I'd use whereis, if it's in the path and you've used it in the past it's going to show you here
where it is well I'm just going to use an example here I installed a tool on this system yesterday
and it's called kite kite runner and so I'm going to go it's called locate I'm going use it for
each and I'm going to go kr is the the name of the file and comes back with lots of examples some
of them which have nothing to do with Kite Runner that's too much information doesn't really help me
anything I can go whereis and whereis will show me where Kite Runner is where the binary is at and
there it is it's under user local bin and then if I go which KR it comes back with nothing why
because this is not in my path directory so I got different results for each one of those commands.
So the one that's probably the most useful for me okay is this command right here whereis it shows
me where the binary resides so to run this command I need to be in this directory right here it will
not work so if I just do command not found right that's something that beginners often run up
against right command I just installed that, I just installed I know it's there why does it
why does it come back with command not found right? Why does it come I I know I have it there
it's there right yeah and yes it is there but it's not going to find it because when you type it like
this it's looking in the directories that are in the path command but this particular directory
is not in the path variable I said path command I meant path variable and I showed you that path
variable just a moment ago. So let's go back and let's just way... I always get asked about and
you you might get asked as well is people want to know where the passwords are stored in Kali
because they've heard about RockYou or they want to do like a Brute Force attack against sorry
a dictionary attack against a Wi-Fi password or some something um and they want to know where the
passwords are stored? Okay well one of the things that you can do in Kali to find all of the word
lists is go locate word lists all right and most of the word list the password lists are under
they're labeled wordless and you can see well there's actually RockYou right there and there's
going to be hundreds of word lists in Kali, so one of the you know there's there's an art
and there's a science to password cracking the the science is the scripts and the tools that we
use the art is going to be selecting or creating the proper password list to use to try to crack
a password and that's something that comes with some experience and not necessarily it's not
something that you know that you can just throw a password cracking tool add a particular password
or hash of a password and be successful selecting the proper password list is part of the art of
doing it properly RockYou is um you know it's an old list has been around for a while what I
prefer other than RockYou is I've got a couple of lists on hackers arise one of them is the top
10,000 most common passwords and the top 1 million most common passwords I prefer to use those first
they're more successful the top 10,000 passwords will cover about 10% of all the possibilities in
other words what we've done is we've collected those passwords that most commonly appear in
the data dumps on the dark web and there's about 10,000 passwords that get used over and
over and over again you can imagine what those are right 1 2 3 4 5 6 7 8 you know I I love you um
you know and some some vulgar ones as well right and so these passwords people think oh you know it
doesn't really matter what password I use as long as it's a number of characters what have you but
people you know human beings are similar and they think similarly and they use similar passwords and
so you can go into the dark web and we've already done this for you and we've collected those
passwords that are most common so you can simply use our 10,000 password list and that's going to
get you about 10 thou 10% of all of the passwords used by people around the world we also have
another list of a top 1 million and that's going to get you about 30% of all the passwords now of
course 30 % it's not 100% but I always recommend when you're doing password cracking that you start
with a simple okay start small okay start simple and this probably applies to life in general start
simple and then work from simple to more complex you don't want to be running RockYou password
list when the password is one 123456 right you know start with a simple small password list see
if it's there if it's not keep on getting into larger and more complex passwords and one of the
things that I always run up against is that people will use RockYou and some of these other password
lists and they'll say I couldn't find it I I ran it for hours days what have you and I couldn't
find the password and I said well what country are you in oh I am I'm I'm in I'm in France right
well you're running an English password list in France right the the the the password is probably
not going to be in English it might be but it's probably not so what you need is a French password
list and so and you can do some searches do some Google searches and find some French, Spanish,
Arabic whatever language password lists that are out there on the web and use those because these
lists you know these are made by English speakers and they're probably not going to apply in all
countries especially if nobody speaks English in your country right? Now one of the things
interesting we found in in in our attacks against Russia is that Russia we found a lot of systems
that had English passwords on them because it is interesting because we didn't expect that not
at all and what we presume is that because a lot of the software is coming from English speaking
countries okay that there's the default passwords are in English and then for whatever reason the
administrators changed them and used English passwords it was a surprise for us so and yeah
we found lots of systems with English passwords for whatever reason not entirely sure why but
we presume it's because almost every case the software that was being used was produced in the
US or the UK and you know it it had everything's in English right the whole all the software is
in English so the administrators put in English passwords in Russia. Let's talk a little bit
about another more powerful tool for finding what you're looking for in Linux and that's the
find command so let's uh there's find and then we can use the dash h and let's take a it says
unknown predicate h, so the h doesn't work for find let's try just using and there when there's
a and find command if we do it it actually does it actually does its work which means find everything
and then we can let's try using dash dash help and there we get their help screen so it took three
times through but took us a moment this is a a really powerful tool for finding information
in your system. So find is is going to find you know previously we were looking for binary
but sometimes we're looking for other things you know like a configuration file, what have you
and find has a really powerful uh capabilities of finding files that by size, by name, by when it
was created all of these things find can do for us but in this very let me clear my screen,
we'll use it for a pretty simple task here, let's say we want to find and the next thing
that we put in in terms of find is where do we want find to look find is going to look through
the entire file system if we don't tell it but we can say start at the top of the file system
right and then we can say what type of file okay what do we want either a directory or do we want
a file we can say type and say file and then we can say how do we want to search for it and say
we want to search by and let's say we want to go find apache2, apache2 is the most widely used
web server in the world and let's see if we have any of those on this system and look at what it
does comes back and says permission denied once again this is something that you'll often find
using a lot of tools a lot of tools in Kali, you'll come back and permission that when you see
that you right away know that you need to be root to be able to do what you want to do so if you
get this message right permission denied what you do is you just simply use the sudo command let's
go up arrow okay let up arrow and then use sudo before it and then it asks me for my password all
right to prove that I'm actually who I am and now it goes ahead and finds apache2 every place that
apache2 is on the system and I still going to come back and tell me that some of them are permission
denied we can get pretty sophisticated with what we can do with the find command but I recommend
that you get familiar with it you can do the man and then find and it'll show you them and there's
a lot that we can use in the find to be very specific about what you're looking for right.
Here's a very long man page on find but what I want to show is another really important concept
okay in getting started in Linux and that's called filtering with grep. So let's talk about
that let's go um ps okay ps is the processes, so ps aux will show me all of the processes on the
system and so there's a lot there these are all of the processes but generally when I use the ps
aux I'm not necessarily looking for all of these processes I'm looking for one in particular so
I can filter out all of this and just look for one particular file all right one particular
process that's running on this system and so I can go ps aux and let's say then I'll go grep
and it says so this right here is the pipe and what the pipe does is it says take this command
right here and take all of its output and then send its output to another command in this case
the grep command and the grep filters for me and only will show me what I'm looking for so maybe
let's say let's look for say the Burp Suite okay I look for the keyword burp and it's got it it's
done some filtering but there's still a lot there you can see it's a burp burp browser here and the
Burp Suite I was using the Burp Suite yesterday obviously and so there's still a lot there um
maybe a better example and this is I'm going to go ahead let's uh back up a little bit I clear my
screen one of the things that that I'll show you in a later class is that there are you can start
and stop processes within Kali or any Linux by what's now known as the system control command so
I'm going to go sudo system control now it used to be that we used to use the service command
it's now service still works but system control is kind of the more modern command and I can go
start and then go apache say let's go apache2 this will start the apache2 web server it did
it okay it started my apache2, so now if I want to see if it's actually running I can go ps aux
and then grep apache2 and now this will tell me it'll show me whether that process so this is will
show me all of the processes and this filters for just this key word apache2 and there we are we've
got instead of all of that stuff that fills up my screen I filtered out for just the keyword apache2
and I see there's multiple processes that are comprising the apache2 um service and so this
would be. So I was just going to say sorry just for people who might be confused what you did
there is you made your terminal window wider you want to make it like much wider and then run the
command again just so people see it's all on one line perhaps. There we go that's much better
yeah so I've gone ahead and uh and asked the system to show me all of the processes and then
filter for just the keyword apache2 and these are all processes that are linked to the apache2
service the web server and you can it'll show me who the user is this case is the root user and
then these are www -data are the standard user on the Apache server and then this last line here is
basically the command looking for notice it says grep so you're going to when you do this you're
going to get the the search itself is a process and so here it is the Kali user me right now is
looking for apache2 so that's the final line here is that command looking for Apache these are all
part of the service that has been started so this is really useful when you're trying to filter out
out a lot of information and so the grep is one of those key terms that you know we're working
from a command line and we've gotten too much information we want something very specific we can
pipe the output okay that's what this is here pipe the output to a filter command grep is a filter
command and then this is the keyword that we're looking for and you see I've gone from this a ps
aux so much information to too much information right to also notice that the last the last
process is the search and then I can go and then I go from that to grep and then apache2
oh that's what I want I didn't want all that other information I've got exactly what I want
on the screen right now and that's uh that's the key. Just for people who missed it if you just
scroll up it show people might be confused and not realize there's a lot of processes right yeah
like crazy right there's crazy. These are all the processes that are running on your system and
many of them are simply started by default when you start your system they're not ones that I
necessarily started but as you're running your system the longer you run it here we yesterday
we were doing API hacking and this is a this is the crappy is a uh is a simulation of a API
tool that we can use for attacking the uh apis so you got lots of things running on here but I
only wanted to see this that's all I wanted to see I want to see the services for Apache I even
though there's a little bit more in this chapter I think we've done a lot and I don't want the
the video to get too long you know we've we've covered a lot of material. OccupyTheWeb I really
want to thank you for sharing your knowledge and you know creating this sort of video companion
guide to your book really appreciate you you know taking all your experience and I've said
this many times but like bringing it down down to like mere mortals level or beginners level
level so I really appreciate you doing that and I really look forward to the to the next video
just for everyone who's watching OccupyTheWeb and I going to hopefully continue with the series
going through his book put your comments below let us know what you want us to cover we've got a
whole bunch of ideas uh time is the biggest issue but hopefully we'll be able to cover a lot of
the the Linux videos on my channel OccupyTheWeb any last words? uh no no last words other than I
love doing these with you David and hopefully we can keep this going anybody who you know wants
to learn more about Linux take a look at my Linux Basics for Hackers you know it's intended to
get you started on the path to becoming a master hacker but the first thing you got to do is you
got to learn Linux so we'll continue to do this and we'll go through the entire book over the next
several months. Great thank you. Thanks David!
