Our favorite way, and the fastest method, for getting up and running with Kali Linux is to run it “live” from a USB drive. This method has several advantages:

• It’s non-destructive — it makes no changes to the host system’s hard drive or installed OS, and to go back to normal operations, you simply remove the “Kali Live” USB drive and restart the system.
• It’s portable — you can carry Kali Linux in your pocket and have it running in minutes on an available system
• It’s customizable — you can roll your own custom Kali Linux ISO image and put it onto a USB drive using the same procedures
• It’s potentially persistent — with a bit of extra effort, you can configure your Kali Linux “live” USB drive to have persistent storage, so the data you collect is saved across reboots

In order to do this, we first need to create a bootable USB drive which has been set up from an ISO image of Kali Linux.

What You’ll Need

1. A verified copy of the appropriate ISO image of the latest Kali build image for the system you’ll be running it on: see the details on downloading official Kali Linux images.
2. If you’re running under Windows, you’ll also need to download the Win32 Disk Imager utility. On Linux and OS X, you can use the dd command, which is pre-installed on those platforms.
3. A USB thumb drive, 4GB or larger. (Systems with a direct SD card slot can use an SD card with similar capacity. The procedure is identical.)

Kali Linux Live USB Install Procedure

The specifics of this procedure will vary depending on whether you’re doing it on a Windows, Linux, orOS X system.

Creating a Bootable Kali USB Drive on Windows

1. Plug your USB drive into an available USB port on your Windows PC, note which drive designator (e.g. “F:\”) it uses once it mounts, and launch the Win32 Disk Imager software you downloaded.
2. Choose the Kali Linux ISO file to be imaged and verify that the USB drive to be overwritten is the correct one. Click the “Write” button.
   
3. Once the imaging is complete, safely eject the USB drive from the Windows machine. You can now use the USB device to boot into Kali Linux.

Creating a Bootable Kali USB Drive on Linux

Creating a bootable Kali Linux USB key in a Linux environment is easy. Once you’ve downloaded and verified your Kali ISO file, you can use the dd command to copy it over to your USB stick using the following procedure. Note that you’ll need to be running as root, or to execute the dd command with sudo. The following example assumes a Linux Mint 17.1 desktop — depending on the distro you’re using, a few specifics may vary slightly, but the general idea should be very similar.

1. First, you’ll need to identify the device path to use to write the image to your USB drive.Without the USB drive inserted into a port, execute the command
   sudo fdisk -l

   at a command prompt in a terminal window (if you don’t use elevated privileges with fdisk, you won’t get any output). You’ll get output that will look something (not exactly) like this, showing a single drive — “/dev/sda” — containing three partitions (/dev/sda1, /dev/sda2, and /dev/sda5):
   

2. Now, plug your USB drive into an available USB port on your system, and run the same command, “sudo fdisk -l” a second time. Now, the output will look something (again, not exactly) like this, showing an additional device which wasn’t there previously, in this example “/dev/sdb”, a 16GB USB drive:
3. Proceed to (carefully!) image the Kali ISO file on the USB device. The example command below assumes that the ISO image you’re writing is named “kali-linux-1.0.9a-amd64.iso” and is in your current working directory. The blocksize parameter can be increased, and while it may speed up the operation of the dd command, it can occasionally produce unbootable USB drives, depending on your system and a lot of different factors. The recommended value, “bs=512k”, is conservative and reliable.
   dd if=kali-linux-1.0.9a-amd64.iso of=/dev/sdb bs=512k

Imaging the USB drive can take a good amount of time, over ten minutes or more is not unusual, as the sample output below shows. Be patient!

The dd command provides no feedback until it’s completed, but if your drive has an access indicator, you’ll probably see it flickering from time to time. The time to dd the image across will depend on the speed of the system used, USB drive itself, and USB port it’s inserted into. Once dd has finished imaging the drive, it will output something that looks like this:

That’s it, really! You can now boot into a Kali Live / Installer environment using the USB device.

Creating a Bootable Kali USB Drive on OS X

OS X is based on UNIX, so creating a bootable Kali Linux USB drive in an OS X environment is similar to doing it on Linux. Once you’ve downloaded and verified your chosen Kali ISO file, you use dd to copy it over to your USB stick.

1. Without the USB drive plugged into the system, open a Terminal window, and type the command diskutil list at the command prompt.
2. You will get a list of the device paths (looking like /dev/disk0, /dev/disk1, etc.) of the disks mounted on your system, along with information on the partitions on each of the disks.
   
3. Plug in your USB device to your Apple computer’s USB port and run the command diskutil list a second time. Your USB drive’s path will most likely be the last one. In any case, it will be one which wasn’t present before. In this example, you can see that there is now a /dev/disk6 which wasn’t previously present.
   
4. Unmount the drive (assuming, for this example, the USB stick is /dev/disk6 — do not simply copy this, verify the correct path on your own system!):

1. Proceed to (carefully!) image the Kali ISO file on the USB device. The following command assumes that your USB drive is on the path /dev/disk6, and you’re in the same directory with your Kali Linux ISO, which is named “kali-linux-1.0.9a-amd64.iso”:

Note: Increasing the blocksize (bs) will speed up the write progress, but will also increase the chances of creating a bad USB stick. Using the given value on OS X has produced reliable images consistently.

Imaging the USB drive can take a good amount of time, over half an hour is not unusual, as the sample output below shows. Be patient!

The dd command provides no feedback until it’s completed, but if your drive has an access indicator, you’ll probably see it flickering from time to time. The time to dd the image across will depend on the speed of the system used, USB drive itself, and USB port it’s inserted into. Once dd has finished imaging the drive, it will output something that looks like this:

And that’s it! You can now boot into a Kali Live / Installer environment using the USB device.

To boot from an alternate drive on an OS X system, bring up the boot menu by pressing the Optionkey immediately after powering on the device and select the drive you want to use.

For more information, see Apple’s knowledge base.