How To: Chrome OS = Your New PenTesting Tool

Chrome OS = Your New PenTesting Tool

Chrome OS = Your New PenTesting Tool

This is my first how-to for this site so feel free to let me know if I can somehow improve!

Inspired by the great Jailbroken iDevice and Rooted Android PenTesting tutorials I decided to share how I use my Toshiba Chromebook 2 with Kali Sana.

Chromebooks have a couple of benefits over traditional laptops. They're extremely light and are nice and cheap! The Toshiba Chromebook 2 which I use retails for around 300$.

With a little bit of tinkering you can get Kali set up on your Chromebook and start hacking away. To do this we will use crouton, an excellent project that you can find on GitHub: https://github.com/dnschneid/crouton

Step 1: Put Your Chromebook into Developer Mode

There are plenty of guides on how to do this online so I'm just going to link to a good one: http://www.howtogeek.com/210817/how-to-enable-developer-mode-on-your-chromebook/

Step 2: Download Crouton

Go to the crouton GitHub page and download the crouton file:
https://github.com/dnschneid/crouton

Make sure the crouton file is in your downloads folder.

Step 3: Install the Crouton Extension

Install the crouton extension from the Chrome Webstore. It greatly improves crouton functionality with features like clipboard sharing and the Linux OS running in a window.

https://chrome.google.com/webstore/detail/crouton-integration/gcpneefbbnfalgjniomfjknbcgkbijom?utm_source=chrome-app-launcher-info-dialog

Step 4: Install Kali Sana

Type ctrl+alt+t to open a crosh shell. Now type shell and hit enter to get a chronos shell.

Type:
sudo sh ~/Downloads/crouton -r sana -t extension,xiwi,kde

Optionally add the following flags:
-e for full disk encryption
-k /PATH-TO-STORE-KEYFILE/KEYFILE-NAME require keyfile to start (best when combined with -e)
-p /PATH-TO-REMOVABLE-MEDIA/ installs Kali Sana on a removable device.

I installed Sana on an SD card to take advantage of the larger storage capacity available. Many Chromebooks only have 16GB of storage which is not enough for a fully decked out Kali installation. Using the -e and -k flags greatly increases the security of the installation. Also make sure to format the SD Card to ext4 prior to installation.

After executing the command, follow the on screen instructions to install Kali. This process may take quite some time, so get a snack and feel free to browse the web while you wait.

Step 5: Start Your New OS!

Now that Sana is installed, you can enter it by typing sudo sh startkde -n sana.

If you installed to an SD Card you will need to type the full path of the file. It will be in /PATH-TO-REMOVABLE-MEDIA/bin/.

This should start Kali. The chrome extension should automatically connect, and you should have your OS open in a nice window! If the window is black at first, wait a bit and try re-sizing it a couple of times.

Step 6: Configure the OS

You can now install Kali Metapackages and any other software you may need.

We're Done!

Congratulations, you now have Kali Sana running on your Chromebook! Keep reading for a couple of tips that may smooth out your experience.

Tips and Tricks

SD Card idle lid suspend fix

If you installed Sana on an SD Card like I did, you will experience problems with idle lid suspend while running crouton. This is due to the fact that Chrome OS sometimes ejects SD cards when the lid is closed, thereby making crouton crash. There is some great information on the crouton GitHub page on how to fix this. The easiest way being to disable idle lid suspend while crouton is running. This way only the screen will turn off while Chrome OS will keep running. This stops your SD Card from getting ejected. Here's the script you can use to start Sana with this modification:

https://github.com/dnschneid/crouton/wiki/Power-manager-overrides

You will have to modify the part of the script that actually starts Sana by adding the startup command you used in Step 5.

Notes on airmon-ng

If you Chromebook has a compatible wifi card you'll be able to use the aircrack-ng suite for pentesting. My Toshiba Chromebook 2 works well with this, the only problem being that when finished and airmon-ng is stopped, it does not rename your wireless device back to what it was before. This is an issue as Chrome OS will not recognize the wireless device and you will not have internet access. To solve this you can either restart you computer, or you can manually rename the interface:

sudo iw dev wlan0mon del
sudo iw phy phy0 interface add wlan0 type managed

These commands will vary depending on the name of you wireless interface.

Notes on external wireless adapters

This is the only downside of running Sana through crouton on Chrome OS. As it shares the Chrome OS kernel, most external wireless adapters will not register. Some people have apparently gotten select cards to work, but I have not been so lucky. The only solution to this is enabling USB-Boot and booting from a Live Kali USB when you need multiple network cards.

That's It Folks!

Hope you enjoyed my tutorial. Feel free to leave suggestions and any questions you may have below. I'll try to answer any that come up.

~The Pacifist

14 Comments

Great tutorial glad to see someone finally giving the public some info on how to configure crouton on chromebooks. The public needs more info on how to configure chromebooks for pentesting.

Only issue I found from using crouton on chromebook was like you said at the end of your post. That the distro running in crouton (in this case Kali Sana), is stuck using the kernel version that chrome OS is using. Kali Sana normally runs on 4.0 kernel and many of the tools are configured and tested to work with the latest kernel. Chrome OS doesn't yet support 4.0.0 kernel build and it is said it won't for a very long time.

So while Kali Sana does function pretty well in crouton, I came across a few issues with getting some tools to work with the outdated kernel.

I went with the alternative of enabling the sea-bios, running a live usb of kali, doing a full install and wipe over chrome OS completely.

Thanks for the feedback! I was considering that but the convenience of having Chrome OS for when I do not need access to anything not internet based is worth having to boot from a USB for better access to tools.

The title is misleading.

But I have a question: Can't you install Kali on chromebooks by simply downloading and burning it on a DVD/USB drive? I mean, they're normal machines, right?

I haven't really ever used a chromebook. I'm not a big fan for chrome, even. It's too unstable for old PCs.

-The Joker

Firstly great tutorial! Secondly, regarding The Joker's question about Chromebook, no they are not like normal computers. A Chromebook is really just a computer that has nothing and can't have anything but Google Chrome on it. You can download Google Chrome extensions but you can install any other software.

Cheers,
Washu

There are actually many chromebooks that are quite powerful and capable of being a fully function laptop computer(Acer C270-3404 for example). Chrome OS however, is like WASHU said, very limited. It lacks many functionalities such as burning an iso to a live CD/USB. It's possible to wipe Chrome OS completely though and have whatever OS you want.

Joker: kali (or any other iso for that matter) can be fully installed via live USB/CD to most chromebooks but requires some effort.

The arch community is very fond of Chromebooks and has a lot of support on it. I provided a few links below:

https://wiki.archlinux.org/index.php/Acer_C720_Chromebook
https://wiki.archlinux.org/index.php/Chrome_OS_devices

what is the command for if you want to install on an sd card like the full command

I'm trying to install kali using Acer C720 laptop, but it keeps getting stuck at some point. When I enter the command
sudo sh ~/Downloads/crouton -r sana -t extension,xiwi,kde

it starts to install kali, but at the very end it asks me something like 'enter the primary user name: ' and from that point on the screen just freezes. Did anybody experience this? I repeated the process about 4 times but still no luck.

Well I found the problem just now. It turns out that the chromebook keyboard was disabled after installation for some reason. I just hooked up my other usb keyboard and could go on from there. But there still persists another issue. When I go into the kde interface using command 'sudo startkde -n sana', it is not Kali linux. It's just empty interface with nothing in it.

I don't know why I'm having this problem. I installed everything right just like the instruction says.

I was googling to several hours to figure out how to install crouton on SD card, and finally got everything done.
First off, you need to format your SD card to ext4 format.
Here's link: http://askubuntu.com/questions/579630/formatting-128gb-sd-card-to-ext4-with-gparted
Second, you need to run this command
"sudo sh -e ~/Downloads/crouton -r trusty -t xfce -e -p /media/removable/SD" (without quotation marks)
here's another link: https://www.reddit.com/r/Crouton/comments/2p7fq8/installing_crouton_on_sd_card_ext4/

SO im having trouble downloading some files.

they are all listed on the bottom of the screen. Can any of you guys help?

Does -e replace Chrome OS with Kali? If not, what does it do? How do you get Kali Rolling?

Ok, I have found that the versions kali and sana are outdated and do not work anymore. Instead of sana , you put kali-rolling. The only problem is that none of the tools were installed for me. Help!

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