Kali Linux

The industry-standard penetration-testing distribution, maintained by Offensive Security and pre-loaded with hundreds of security auditing and exploitation tools.

Security, Privacy & Anonymitysecuritypenetration-testingoffensive-securityDebian-basedDownload ↗Official site ↗Docs / Wiki ↗

Based on

Debian

First released

2013

Package manager

APT (.deb)

Desktop environments

Xfce (default), GNOME, KDE Plasma

Kali Linux is the direct successor to BackTrack Linux and has become the default OS for penetration testers, red teams, and security certification courses (Offensive Security's own OSCP among them), shipping with tools like Nmap, Metasploit, Wireshark, Burp Suite, Aircrack-ng, and hundreds of others ready to use out of the box. It's built on Debian Testing and offers specialized build variants -- Kali NetHunter for Android devices, Kali ARM images for Raspberry Pi and similar boards, and pre-built VM/cloud images -- alongside the standard desktop ISO. As with any penetration-testing toolkit, its tools are intended strictly for systems you own or are explicitly authorized to test; running them against systems without authorization is illegal in most jurisdictions.

MirrorNest doesn't mirror distro ISOs — installation media should always come straight from the project's own official download page (linked above), so you get the correct checksum/signature to verify against.