This post is about the Kali Linux distribution and how it is used by cybersecurity professionals. If you’d like to find out about learning Linux, you can see our article here.

When you start looking into a career in cybersecurity, one of the biggest things you will quickly learn is how important Kali Linux is to cybersecurity professionals and especially professional penetration testers. In case you’re not familiar with this very interesting version of Linux, in this article, we’ll dive into what exactly Kali Linux is and discuss the best way to learn this penetration testing swiss army knife operating system.

So, what is Kali Linux? Kali Linux is a Debian-based version of the operating system Linux, which has been specifically built for penetration testing and digital forensics. One of the main aspects of Kali Linux is its pre-installed security tool suite that can be used for a variety of cybersecurity purposes, including penetration testing and exploitation.  Kali Linux is free to download.

Because Kali Linux includes many tools and is available for free, it has become very important to cybersecurity professionals and the cybersecurity industry.  Let’s go over a brief history of why Kali was created and why it’s so important to the field.

A brief history of Kali Linux

Kali Linux was released in 2013 by the organization Offensive Security, which also offers cybersecurity training and certifications.  Offensive Security took the pre-existing security-focused Backtrack Linux and redeveloped it into Kali based on the Debian variant of Linux.  Kali Linux is free and it is made very clear that it will always be free. 

Kali Linux and its role in cybersecurity

One of the greatest features of Kali Linux is the fact that is has pre-installed tools which can be used for a tremendous number of cybersecurity-related tasks. There are more than 600 tools included in Kali Linux for penetration testing and cybersecurity purposes, and the Kali distro is continually updated and improved by Offensive Security.

Why do cybersecurity professionals prefer Kali Linux?

One of the biggest reasons cyber professionals use and often prefer Kali Linux is the fact that all of the  original source code is open source, meaning that the system can be tweaked to the liking of the cybersecurity professional that is using it.  Which this is not necessarily done often, it does provide the option to personalize Kali for specific cybersecurity tasks. Kali Linux also comes with multi language support.

Interestingly, up until 2019 Kali Linux had been designed to be used for single root user access, meaning that the user is given full rights and access to everything.  This was recently changed to accommodate users that were using Kali Linux more often than just for cybersecurity purposes.

Can I download Kali as my main operating system?

While it can be, and sometimes is done, using Kali Linux as your default daily operating system is not ideal or even recommended by Offensive Security, due to the security focus of the OS and the fact that there are other Linux versions that are considered more stable.  Most installations of Kali Linux exist as either a bootable live disk or as a virtual machine hosted by another operating system.

Popular tools of Kali Linux

The pre-installed cybersecurity tools are the major factor in the popularity of Kali Linux.  Lets spend a few moments to go over a few of the most popular and useful as an example of what Kali Linux can do for us as cybersecurity professionals. 


Metasploit is a penetration testing tool that makes hacking far easier for cyber professionals. It takes processes that used to be manual, such as information gathering, gaining access, and evading detection and automates them. Metasploit is extremely popular and highly used by professionals in the information security field, and it is a great way to test exploits and vulnerabilities.

John the Ripper

John the ripper is a password cracking tool that is customizable and combines numerous cracking modes to suit individual needs. The best part is it can be run against various encrypted password formats, and it  can perform password cracking techniques, such as dictionary and brute force attacks.


Netcat is a network tool which is used to read and write data across network connections. Netcat includes a list of features from port scanning to transferring files to port listening. Netcat can create almost any kind of connection you would need and is a preferred tool for port scanning. 


Wireshark is an open-source packet analyzer and it is used to see and evaluate traffic on a network, which makes it essential for any security professional or systems administrator.  When run and analyzed live, it is a real time indicator of what traffic is going across the network, and can even be used for troubleshooting.

The cyber advantage of using Kali Linux

Those were just a few examples of the popular applications that come pre-installed on Kali Linux. While it is true that all of the applications on Kali Linux are free and can be downloaded on other operating systems, Kali Linux makes it a lot easier for the user by doing all of the work for you and compiling them in one operating system distribution.

What is the best way to learn Kali?

If you’re ready to start learning the Kali Linux operating system and how it can be used for cybersecurity, follow the steps below.

  1.  Start with building a Kali Linux virtual machine

There are many freeware ways to set up a hypervisor and begin working with virtual machines, including  a Kali Linux deployment. A virtual machine environment will enable you to set up and tear down one, even multiple instances of Kali Linux and take snapshots along the way.

Start by installing a free hypervisor, such as Oracle’s VirtualBox.  Once installed, you can download and install into a virtual machine the Kali Linux ISO.  If you are unfamiliar with Linux in general, you may want to also install other free distributions of Linux and build them into their own virtual machines, such as Ubuntu or CentOS.  Check videos on YouTube if you get stuck or need some direction.  

  1. Explore the cyber tools in Kali Linux

Once you have Kali Linux installed into a VM, take a look at the various tools that are built into the operating system.  You’ll note that they are sorted by category. A good way to begin is to choose one tool at a time and learn them one by one.  Choose one tool from within a category of interest and start working with it, using online tutorials as needed to work your way through the tool’s options.  There are plenty of tutorials on YouTube that can help you navigate throughout the numerous Kali tools and utilities. Try to focus on learning one tool at a time because learning one tool will often make learning another tool easier as you go. 

While you’re working with these tools, do not use them against any system that you do not own or have authorization to access, as using these tools in this manner is illegal.

  1.  Attempt to use these tools against legal hacking sites

While it is illegal to attempt to hack into any site which you are not authorized to attack, there fortunately are several sites online that are set up for exactly this purpose, in that they allow you to attempt to exploit them legally.  Do an internet search to see which sites are available and can be used with the tool that you are testing, and read any disclaimers. It shouldn’t be difficult to find a website that you are legally allowed to attempt an exploit for free.

Conclusion and Key Points

  • Keep in mind that Kali Linux, while not overly complicated, isn’t exactly for beginners, so take your time as you work through the tools.  Try to learn at least one new thing each day.
  • If you’re new to the world of Linux, consider starting with another Linux system like Ubuntu to get a taste of what you would be getting into.
  • Never attempt to use the tools in Kali Linux against any system which are not authorized to access.  There are plenty of legally free systems out there to practice your skills.
  • Keep in mind that all of the tools that you need are free.  From free virtual machine hypervisors, to free operating systems, to cybersecurity tools and Kali Linux itself, learning cybersecurity is mostly an investment of your time and effort.

About the author 

Matt Day

Matt Day is a cybersecurity professional with over twenty years of experience in the IT, cybersecurity, and technology training fields. He has a degree in Computer Information Science and CompTIA A+, Network+, Security+, Server+, CySA+, and Cisco CCNA certifications.