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Vol. 1 · Ed. 2026
CyberGlossary
Entry № 577

Kali Linux

What is Kali Linux?

Kali LinuxA Debian-based Linux distribution from OffSec that pre-packages hundreds of penetration testing, red-teaming, and digital forensics tools.


Kali Linux is a free, open-source operating system maintained by OffSec (formerly Offensive Security), the successors of the earlier BackTrack project. It ships with curated tool sets for reconnaissance (Nmap, recon-ng), exploitation (Metasploit, Burp Suite), wireless attacks (Aircrack-ng), forensics, reverse engineering, and red-team operations, and runs on x86, ARM, WSL, cloud, and container images. Security professionals use Kali as a portable platform for pentest engagements, CTF challenges, and training (notably the OSCP exam). Although the OS itself is legal to install, running its tools against systems without explicit authorization remains unlawful.

Examples

  1. 01

    Booting a Kali live USB on a customer site to run a network pentest from an isolated laptop.

  2. 02

    Using Kali NetHunter on a rooted Android device to test Wi-Fi defenses during a red-team operation.

Frequently asked questions

What is Kali Linux?

A Debian-based Linux distribution from OffSec that pre-packages hundreds of penetration testing, red-teaming, and digital forensics tools. It belongs to the Defense & Operations category of cybersecurity.

What does Kali Linux mean?

A Debian-based Linux distribution from OffSec that pre-packages hundreds of penetration testing, red-teaming, and digital forensics tools.

How does Kali Linux work?

Kali Linux is a free, open-source operating system maintained by OffSec (formerly Offensive Security), the successors of the earlier BackTrack project. It ships with curated tool sets for reconnaissance (Nmap, recon-ng), exploitation (Metasploit, Burp Suite), wireless attacks (Aircrack-ng), forensics, reverse engineering, and red-team operations, and runs on x86, ARM, WSL, cloud, and container images. Security professionals use Kali as a portable platform for pentest engagements, CTF challenges, and training (notably the OSCP exam). Although the OS itself is legal to install, running its tools against systems without explicit authorization remains unlawful.

How do you defend against Kali Linux?

Defences for Kali Linux typically combine technical controls and operational practices, as detailed in the full definition above.

What are other names for Kali Linux?

Common alternative names include: Kali, BackTrack successor.

Related terms

See also