KALI LINUX
INTRODUCTION
Linux Structure
History
Many events led up to creating the first Linux kernel and, ultimately, the Linux operating syste
the Unix operating system's release by Ken Thompson and Dennis Ritchie (whom both worke
time) in 1970. The Berkeley Software Distribution (BSD) was released in 1977, but since it con
owned by AT&T, a resulting lawsuit limited the development of BSD. Richard Stallman started
1983. His goal was to create a free Unix-like operating system, and part of his work resulted
Public License (GPL) being created. Projects by others over the years failed to result in a wor
would become widely adopted until the creation of the Linux kernel.
At first, Linux was a personal project started in 1991 by a Finnish student named Linus Torvald
create a new, free operating system kernel. Over the years, the Linux kernel has gone from a
written in C under licensing that prohibited commercial distribution to the latest version with o
code lines (comments excluded), licensed under the GNU General Public License v2.
Linux is available in over 600 distributions (or an operating system based on the Linux kernel
software and libraries). Some of the most popular and well-known being Ubuntu, Debian, Fed
elementary, Manjaro, Gentoo Linux, RedHat, and Linux Mint.
Linux is generally considered more secure than other operating systems, and while it has had
vulnerabilities in the past, it is becoming less and less frequent. It is less susceptible to malw
operating systems and is very frequently updated. Linux is also very stable and generally affo
performance to the end-user. However, it can be more difficult for beginners and does not ha
hardware drivers as Windows.
Since Linux is free and open-source, the source code can be modified and distributed comm
commercially by anyone. Linux-based operating systems run on servers, mainframes, deskto
systems such as routers, televisions, video game consoles, and more. The overall Android op
runs on smartphones and tablets is based on the Linux kernel, and because of this, Linux is t
installed operating system.
Linux is an operating system like Windows, iOS, Android, or macOS. An OS is software that m
hardware resources associated with our computer. That means that an OS manages the who
between software and hardware. Also, there exist many different distributions (distro). It is lik
Windows operating systems.
With the interactive instances, we get access to the Pwnbox, a customized version of Parrot
, Linux is designed to work mainly with
Avoid captive user interfaces which gives the user greater control o
system.
An example of such a file is the /etc/
Configuration data stored in a text file
stores all users registered on the syst
Components
Component Description
A piece of code that runs to guide the booting process to start the operating system.
Bootloader
uses the GRUB Bootloader.
The kernel is the main component of an operating system. It manages the resources
OS Kernel
I/O devices at the hardware level.
Background services are called "daemons" in Linux. Their purpose is to ensure that k
Daemons such as scheduling, printing, and multimedia are working correctly. These small prog
after we booted or log into the computer.
The operating system shell or the command language interpreter (also known as the
OS Shell line) is the interface between the OS and the user. This interface allows the user to te
what to do. The most commonly used shells are Bash, Tcsh/Csh, Ksh, Zsh, and Fish.
This provides a graphical sub-system (server) called "X" or "X-server" that allows gr
Graphics server
programs to run locally or remotely on the X-windowing system.
Also known as a graphical user interface (GUI). There are many options, including GN
MATE, Unity, and Cinnamon. A desktop environment usually has several applications
Window Manager
file and web browsers. These allow the user to access and manage the essential and
accessed features and services of an operating system.
Applications or utilities are programs that perform particular functions for the user or
Utilities
program.
Linux Architecture
The Linux operating system can be broken down into layers:
Layer Description
Hardware Peripheral devices such as the system's RAM, hard drive, CPU, and others.
The core of the Linux operating system whose function is to virtualize and control com
computer hardware resources like CPU, allocated memory, accessed data, and others
Kernel
kernel gives each process its own virtual resources and prevents/mitigates conflicts b
different processes.
A command-line interface (CLI), also known as a shell that a user can enter command
Shell
execute the kernel's functions.
System Utility Makes available to the user all of the operating system's functionality.
,Path Description
The top-level directory is the root filesystem and contains all of the files required to bo
the operating system before other filesystems are mounted, as well as the files require
/
to boot the other filesystems. After boot, all of the other filesystems are mounted at
standard mount points as subdirectories of the root.
/bin Contains essential command binaries.
Consists of the static bootloader, kernel executable, and files required to boot the Linux
/boot
OS.
Contains device files to facilitate access to every hardware device attached to the
/dev
system.
Local system configuration files. Configuration files for installed applications may be
/etc
saved here as well.
/home Each user on the system has a subdirectory here for storage.
/lib Shared library files that are required for system boot.
/media External removable media devices such as USB drives are mounted here.
/mnt Temporary mount point for regular filesystems.
/opt Optional files such as third-party tools can be saved here.
, Linux distributions - or distros - are operating systems based on the Linux kernel. They are u
purposes, from servers and embedded devices to desktop computers and mobile phones. Ea
is different, with its own set of features, packages, and tools. Some popular examples include
Ubuntu
Fedora
CentOS
Debian
Red Hat Enterprise Linux
Many users choose Linux for their desktop computers because it is free, open source, and hi
Ubuntu and Fedora are two popular choices for desktop Linux and beginners. It is also widely
operating system because it is secure, stable, and reliable and comes with frequent and regu
we, as cybersecurity specialists, often prefer Linux because it is open source, meaning its so
available for scrutiny and customization. Because of such customization, we can optimize an
Linux distribution the way we want and configure it for specific use cases only if necessary.
We can use those distros everywhere, including (web) servers, mobile devices, embedded sy
computing, and desktop computing. For cyber security specialists, some of the most popular
are but are not limited to:
ParrotOS Ubuntu Debian
Raspberry Pi OS CentOS BackBox
BlackArch Pentoo
The main differences between the various Linux distributions are the included packages, the
the tools available. Kali Linux is the most popular distribution for cyber security specialists, in
of security-focused tools and packages. Ubuntu is widespread for desktop users, while Debi
servers and embedded systems. Finally, red Hat Enterprise Linux and CentOS are popular for
computing.
Debian
Debian is a widely used and well-respected Linux distribution known for its stability and reliab
various purposes, including desktop computing, servers, and embedded system. It uses an A
Tool ( apt ) package management system to handle software updates and security patches. T
management system helps keep the system up-to-date and secure by automatically downloa
security updates as soon as they are available. This can be executed manually or set up auto
Debian can have a steeper learning curve than other distributions, but it is widely regarded a
flexible and customizable Linux distros. The configuration and setup can be complex, but it a
excellent control over the system, which can be good for advanced users. The more control w
system, the more complex it feels to become. However, it just feels that way compared to the
INTRODUCTION
Linux Structure
History
Many events led up to creating the first Linux kernel and, ultimately, the Linux operating syste
the Unix operating system's release by Ken Thompson and Dennis Ritchie (whom both worke
time) in 1970. The Berkeley Software Distribution (BSD) was released in 1977, but since it con
owned by AT&T, a resulting lawsuit limited the development of BSD. Richard Stallman started
1983. His goal was to create a free Unix-like operating system, and part of his work resulted
Public License (GPL) being created. Projects by others over the years failed to result in a wor
would become widely adopted until the creation of the Linux kernel.
At first, Linux was a personal project started in 1991 by a Finnish student named Linus Torvald
create a new, free operating system kernel. Over the years, the Linux kernel has gone from a
written in C under licensing that prohibited commercial distribution to the latest version with o
code lines (comments excluded), licensed under the GNU General Public License v2.
Linux is available in over 600 distributions (or an operating system based on the Linux kernel
software and libraries). Some of the most popular and well-known being Ubuntu, Debian, Fed
elementary, Manjaro, Gentoo Linux, RedHat, and Linux Mint.
Linux is generally considered more secure than other operating systems, and while it has had
vulnerabilities in the past, it is becoming less and less frequent. It is less susceptible to malw
operating systems and is very frequently updated. Linux is also very stable and generally affo
performance to the end-user. However, it can be more difficult for beginners and does not ha
hardware drivers as Windows.
Since Linux is free and open-source, the source code can be modified and distributed comm
commercially by anyone. Linux-based operating systems run on servers, mainframes, deskto
systems such as routers, televisions, video game consoles, and more. The overall Android op
runs on smartphones and tablets is based on the Linux kernel, and because of this, Linux is t
installed operating system.
Linux is an operating system like Windows, iOS, Android, or macOS. An OS is software that m
hardware resources associated with our computer. That means that an OS manages the who
between software and hardware. Also, there exist many different distributions (distro). It is lik
Windows operating systems.
With the interactive instances, we get access to the Pwnbox, a customized version of Parrot
, Linux is designed to work mainly with
Avoid captive user interfaces which gives the user greater control o
system.
An example of such a file is the /etc/
Configuration data stored in a text file
stores all users registered on the syst
Components
Component Description
A piece of code that runs to guide the booting process to start the operating system.
Bootloader
uses the GRUB Bootloader.
The kernel is the main component of an operating system. It manages the resources
OS Kernel
I/O devices at the hardware level.
Background services are called "daemons" in Linux. Their purpose is to ensure that k
Daemons such as scheduling, printing, and multimedia are working correctly. These small prog
after we booted or log into the computer.
The operating system shell or the command language interpreter (also known as the
OS Shell line) is the interface between the OS and the user. This interface allows the user to te
what to do. The most commonly used shells are Bash, Tcsh/Csh, Ksh, Zsh, and Fish.
This provides a graphical sub-system (server) called "X" or "X-server" that allows gr
Graphics server
programs to run locally or remotely on the X-windowing system.
Also known as a graphical user interface (GUI). There are many options, including GN
MATE, Unity, and Cinnamon. A desktop environment usually has several applications
Window Manager
file and web browsers. These allow the user to access and manage the essential and
accessed features and services of an operating system.
Applications or utilities are programs that perform particular functions for the user or
Utilities
program.
Linux Architecture
The Linux operating system can be broken down into layers:
Layer Description
Hardware Peripheral devices such as the system's RAM, hard drive, CPU, and others.
The core of the Linux operating system whose function is to virtualize and control com
computer hardware resources like CPU, allocated memory, accessed data, and others
Kernel
kernel gives each process its own virtual resources and prevents/mitigates conflicts b
different processes.
A command-line interface (CLI), also known as a shell that a user can enter command
Shell
execute the kernel's functions.
System Utility Makes available to the user all of the operating system's functionality.
,Path Description
The top-level directory is the root filesystem and contains all of the files required to bo
the operating system before other filesystems are mounted, as well as the files require
/
to boot the other filesystems. After boot, all of the other filesystems are mounted at
standard mount points as subdirectories of the root.
/bin Contains essential command binaries.
Consists of the static bootloader, kernel executable, and files required to boot the Linux
/boot
OS.
Contains device files to facilitate access to every hardware device attached to the
/dev
system.
Local system configuration files. Configuration files for installed applications may be
/etc
saved here as well.
/home Each user on the system has a subdirectory here for storage.
/lib Shared library files that are required for system boot.
/media External removable media devices such as USB drives are mounted here.
/mnt Temporary mount point for regular filesystems.
/opt Optional files such as third-party tools can be saved here.
, Linux distributions - or distros - are operating systems based on the Linux kernel. They are u
purposes, from servers and embedded devices to desktop computers and mobile phones. Ea
is different, with its own set of features, packages, and tools. Some popular examples include
Ubuntu
Fedora
CentOS
Debian
Red Hat Enterprise Linux
Many users choose Linux for their desktop computers because it is free, open source, and hi
Ubuntu and Fedora are two popular choices for desktop Linux and beginners. It is also widely
operating system because it is secure, stable, and reliable and comes with frequent and regu
we, as cybersecurity specialists, often prefer Linux because it is open source, meaning its so
available for scrutiny and customization. Because of such customization, we can optimize an
Linux distribution the way we want and configure it for specific use cases only if necessary.
We can use those distros everywhere, including (web) servers, mobile devices, embedded sy
computing, and desktop computing. For cyber security specialists, some of the most popular
are but are not limited to:
ParrotOS Ubuntu Debian
Raspberry Pi OS CentOS BackBox
BlackArch Pentoo
The main differences between the various Linux distributions are the included packages, the
the tools available. Kali Linux is the most popular distribution for cyber security specialists, in
of security-focused tools and packages. Ubuntu is widespread for desktop users, while Debi
servers and embedded systems. Finally, red Hat Enterprise Linux and CentOS are popular for
computing.
Debian
Debian is a widely used and well-respected Linux distribution known for its stability and reliab
various purposes, including desktop computing, servers, and embedded system. It uses an A
Tool ( apt ) package management system to handle software updates and security patches. T
management system helps keep the system up-to-date and secure by automatically downloa
security updates as soon as they are available. This can be executed manually or set up auto
Debian can have a steeper learning curve than other distributions, but it is widely regarded a
flexible and customizable Linux distros. The configuration and setup can be complex, but it a
excellent control over the system, which can be good for advanced users. The more control w
system, the more complex it feels to become. However, it just feels that way compared to the
