Kali Linux is a Linux distribution optimized for penetration testing. It is maintained and managed by offensive security specialists. This distro was born in 2006 under the name BackTrack Linux, but after a significant overhaul in 2013, it was renamed Kali. Kali is based on Debian Testing and includes more than hundreds of security tools, including the big ones like Nmap, Metasploit, and Aircrack-ng, but also a wide variety of more obscure and specialized tools.

You can download and use Kali for free. Still, it is designed as a specialized Linux distribution, optimized for penetration testing, not as a daily operating system for checking your email or browsing the web or sharing kitten gifs.

Who is Kali for?

Kali is a specialized Linux distribution for experienced Linux users who need an offensive penetration testing platform focused on security. “If you’re not familiar with Linux in general, if you don’t have at least a basic level of competence in system administration, if you’re looking for a Linux distribution to use as a learning tool to familiarize yourself with Linux, or if you want a distribution that you can use as a general-purpose desktop installation, Kali Linux is probably not what you’re looking for,” the Kali administrators explain on their site.

Kali Special Features

Kali supports all kinds of case studies, including ARM support (Raspberry Pi), an analysis mode, a “Kali for Android” called NetHunter, Amazon EC2 AWS images, and even Braille support. Most of these are advanced use cases that a beginner probably won’t need to know about, but the world of Kali is vast and popular.

As for the name Kali, it means, among other things, the Hindu goddess of preservation, transformation, and destruction, divine mother (of Ramakrishna), Filipino martial art, or severe in Swahili. But for the OS administrators, Kali is simply the name we found for our new distribution.”

How to Start With Kali

If you are familiar with Linux, especially with a version of Debian like Ubuntu (or, well, Debian directly), then Kali will look familiar, at least at first. Open a terminal and browse around. It is officially recognized as a compliant variant of Debian by the Debian project, and with a GNOME desktop by default, it has the look and feel you can expect at first glance.

Popular Kali tools

Imagine a Swiss Army knife with several hundred gadgets. For Kali, it’s Metasploit, the popular penetration test frame. Another example is Nmap, the indispensable port scanner. And Wireshark, the ubiquitous network traffic analyzer. And of course, Aircrack-ng, for testing WiFi security.

To manage network traffic, you can choose between mitmproxy and Burp (free version). To crack offline passwords? Hashcat and John the Ripper will do the job. Start your day by injecting SQL? Sqlmap is an excellent place to start. To create phishing emails as part of a test campaign, social-engineering tools—such as the Social-Engineer Toolkit (SET)—will continue to play the inattentive employee.