Kali Linux is preinstalled with over 600 penetration-testing programs, including nmap (a port scanner), Wireshark (a packet analyzer), John the Ripper (a password cracker), Aircrack-ng (a software suite for penetration-testing wireless LANs), Burp suite and OWASP ZAP (both web application security scanners). Kali Linux can run natively when installed on a computer's hard disk, can be booted from a live CD or live USB, or it can run within a virtual machine. It is a supported platform of the Metasploit Project's Metasploit Framework, a tool for developing and executing security exploits.

It was developed by Mati Aharoni and Devon Kearns of Offensive Security through the rewrite of BackTrack, their previous forensics Linux distribution based on Ubuntu. The third core developer Raphaël Hertzog joined them as Debian expert.

Kali Linux is based on Debian Wheezy. Most packages Kali uses are imported from the Debian repositories.

Kali Linux is developed in a secure location with only a small number of trusted people that are allowed to commit packages, with each package being signed by the developer. Kali also has a custom built kernel tha is patched for injection. This was primarily added because the development team found they needed to do a lot of wireless assessments.

What's New:

Today we have released the newest version of Kali Linux, 2021.3 (quarter #3), which is now ready for download or updating.

A summary of the changes since the 2021.2 release from June are:

  • OpenSSL - Wide compatibility by default - Keep reading for what that means
  • New Kali-Tools site - Following the footsteps of Kali-Docs, Kali-Tools has had a complete refresh
  • Better VM support in the Live image session - Copy & paste and drag & drop from your machine into a Kali VM by default
  • New tools - From adversary emulation, to subdomain takeover to Wi-Fi attacks
  • Kali NetHunter smartwatch - first of its kind, for TicHunter Pro
  • KDE 5.21 - Plasma desktop received a version bump

OpenSSL: wide compatibility by default

Going forwards from Kali Linux 2021.3, OpenSSL has now been configured for wider compatibility to allow Kali to talk to as many services as possible. This means that legacy protocols (such as TLS 1.0 and TLS 1.1) and older ciphers are enabled by default. This is done to help increase Kali’s ability to talk to older, obsolete systems and servers that are still using these older protocols. This may potentially increase your options on available attack surfaces (if your target has these End of Life (EoL) services running, having then forgotten about them, what else could this uncover?). While this is not a configuration that would be good for a general purpose operating systems, this setting makes sense for Kali as it enables the user to engage and talk with more potential targets.

This setting is easy to modify via the command-line tool kali-tweaks though. Enter the Hardening section, and from there you can configure OpenSSL for Strong Security mode instead, which uses today’s current modern standard allowing for secure communication.

Virtualization: improvements all over the place

The Kali Live image received some love during this release cycle! We worked hard to make the experience smoother for those who run the Live image in virtualized environments. Basic features like copy’n’paste and drag’n’drop between the host and the guest should now work out of the box. And this is really for everyone: VMware, VirtualBox, Hyper-V and QEMU+Spice. Did we forget anyone? Drop us a word on the Kali bug tracker!

On the same line: it’s now very easy to configure Kali for Hyper-V Enhanced Session Mode. Open kali-tweaks in a terminal, select Virtualization, and if Kali is running under Hyper-V, you’ll see a setting to turn on Hyper-V Enhanced Session Mode. It’s now as simple as hitting Enter!

If you use this feature, make sure to visit kali.org/docs/virtualization/install-hyper-v-guest-enhanced-session-mode/, as there are a few additional things to be aware of.

Many thanks to @Shane Bennett, who spent a tremendous amount of time testing this feature, provided extremely detailed feedback all along, and even helped us with the documentation. Kudos Shane!