Kali Linux Revealed

Mastering the Penetration Testing Distribution

by Raphaël Hertzog, Jim O’Gorman, and Mati Aharoni

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Book Details

Price	2.00 USD
Pages	341 p
File Size	10,095 KB
File Type	PDF format
ISBN	978-0-9976156-0-9 (paperback)
Copyright	2017 Raphaël Hertzog,  Jim O’Gorman, and Mati Aharoni

Acknowledgments of Raphaël Hertzog

I would like to thank Mati Aharoni: in 2012, he got in touch with me because I was one out of

dozens of Debian consultants and he wanted to build a successor to BackTrack that would be based

on Debian. That is how I started to work on Kali Linux, and ever since I have enjoyed my journey

in the Kali world.

Over the years, Kali Linux got closer to Debian GNU/Linux, notably with the switch to Kali Rolling,

based on Debian Testing. Now most of my work, be it on Kali or on Debian, provides benefits to the

entire Debian ecosystem. And this is exactly what keeps me so motivated to continue, day after

day, month after month, year after year.

Working on this book is also a great opportunity that Mati offered me. It is not the same kind

of work but it is equally rewarding to be able to help people and share with them my expertise

of the Debian/Kali operating system. Building on my experience with the Debian Administrator’s

Handbook, I hope that my explanations will help you to get started in the fast-moving world of

computer security.

I would also like to thank all the Offensive Security persons who were involved in the book: Jim

O’Gorman (co-author of some chapters), Devon Kearns (reviewer), Ron Henry (technical editor),

Joe Steinbach and Tony Cruse (project managers). And thank you to Johnny Long who joined to

write the preface but ended up reviewing the whole book.

Acknowledgments of Jim O’Gorman

I would like to thank everyone involved in this project for their contributions, of which mine were

only a small part. This book, much like Kali Linux itself was a collaborative project of many hands

making light work. Special thanks to Raphaël, Devon, Mati, Johnny, and Ron for taking on the

lion’s share of the effort. Without them, this book would not have come together.

Acknowledgments of Mati Aharoni

It has been a few years since Kali Linux was first released, and since day one, I have always dreamt

of publishing an official book which covers the Kali operating system as a whole. It is therefore

a great privilege for me to finally see such a book making it out to the public. I would like to

sincerely thank everyone involved in the creation of this project—including Jim, Devon, Johnny,

and Ron. A very special thanks goes to Raphaël for doing most of the heavy lifting in this book,

and bringing in his extensive expertise to our group.

Foreword

The sixteen high-end laptops ordered for your pentesting team just arrived, and you have been

tasked to set them up—for tomorrow’s offsite engagement. You install Kali and boot up one of the

laptops only to find that it is barely usable. Despite Kali’s cutting-edge kernel, the network cards

and mouse aren’t working, and the hefty NVIDIA graphics card and GPU are staring at you blankly,

because they lack properly installed drivers. You sigh.

In Kali Live mode, you quickly type lspci into a console, then squint. You scroll through the

hardware listing: “PCI bridge, USB controller, SATA controller. Aha! Ethernet and Network controllers.”

A quick Google search for their respective model numbers, cross referenced with the

Kali kernel version, reveals that these cutting-edge drivers haven’t reached the mainline kernel yet.

But all is not lost. A plan is slowly formulating in your head, and you thank the heavens for the

Kali Linux Revealed book that you picked up a couple of weeks ago. You could use the Kali Live-

Build system to create a custom Kali ISO, which would have the needed drivers baked into the

installation media. In addition, you could include the NVIDIA graphics drivers as well as the CUDA

libraries needed to get that beast of a GPU to talk nicely to hashcat, and have it purr while cracking

password hashes at blistering speeds. Heck, you could even throw in a custom wallpaper with a

Microsoft Logo on it, to taunt your team at work.

Since the hardware profiles for your installations are identical, you add a preseeded boot option to

the ISO, so that your team can boot off a USB stick and have Kali installed with no user interaction—

the installation takes care of itself, full disk encryption and all.

Perfect! You can now generate an updated version of Kali on demand, specifically designed and

optimized for your hardware. You saved the day. Mission complete!

With the deluge of hardware hitting the market, this scenario is becoming more common for

those of us who venture away from mainstream operating systems, in search of something leaner,

meaner, or more suitable to our work and style.

This is especially applicable to those attracted to the security field, whether it be an alluring hobby,

fascination, or line of work. As newcomers, they often find themselves stumped by the environment

or the operating system. For many newcomers Kali is their first introduction to Linux.

We recognized this shift in our user base a couple of years back, and figured that we could help

our community by creating a structured, introductory book that would guide users into the world

of security, while giving them all the Linux sophistication they would need to get started. And so,

the Kali book was born—now available free over the Internet for the benefit of anyone interested

in entering the field of security through Kali Linux.

As the book started taking shape, however, we quickly realized that there was untapped potential.

This would be a great opportunity to go further than an introductory Kali Linux book and explore

some of the more interesting and little-known features. Hence, the name of the book: 

Kali Linux Revealed.

By the end, we were chuffed with the result. The book answered all our requirements and I’m

proud to say it exceeded our expectations. We came to the realization that we had inadvertently

enlarged the book’s potential user base. It was no longer intended only for newcomers to the

security field, but also included great information for experienced penetration testers who needed

to improve and polish their control of Kali Linux—allowing them to unlock the full potential of

our distribution. Whether they were fielding a single machine or thousands across an enterprise,

making minor configuration changes or completely customizing down to the kernel level, building

their own repositories, touching the surface or delving deep into the amazing Debian package

management system, Kali Linux Revealed provides the roadmap.

With your map in hand, on behalf of myself and the entire Kali Linux team, I wish you an exciting,

fun, fruitful, and “revealing” journey!

Muts, February 2017

Table of Contents

1. About Kali Linux 1

1.1 A Bit of History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.2 Relationship with Debian . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1.2.1 The Flow of Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1.2.2 Managing the Difference with Debian . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1.3 Purpose and Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

1.4 Main Kali Linux Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

1.4.1 A Live System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

1.4.2 Forensics Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

1.4.3 A Custom Linux Kernel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

1.4.4 Completely Customizable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

1.4.5 A Trustable Operating System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

1.4.6 Usable on a Wide Range of ARM Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

1.5 Kali Linux Policies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

1.5.1 Single Root User by Default . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

1.5.2 Network Services Disabled by Default . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

1.5.3 A Curated Collection of Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

1.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2. Getting Started with Kali Linux 13

2.1 Downloading a Kali ISO Image . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

2.1.1 Where to Download . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

2.1.2 What to Download . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

2.1.3 Verifying Integrity and Authenticity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Relying on the TLS-Protected Website . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Relying on PGP’s Web of Trust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

2.1.4 Copying the Image on a DVD-ROM or USB Key . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Creating a Bootable Kali USB Drive on Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Creating a Bootable Kali USB Drive on Linux . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Creating a Bootable Kali USB Drive on OS X/macOS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

2.2 Booting a Kali ISO Image in Live Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

2.2.1 On a Real Computer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

2.2.2 In a Virtual Machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Preliminary Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

VirtualBox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

VMware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

2.3 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

3. Linux Fundamentals 47

3.1 What Is Linux and What Is It Doing? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

3.1.1 Driving Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

3.1.2 Unifying File Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

3.1.3 Managing Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

3.1.4 Rights Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

3.2 The Command Line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

3.2.1 How To Get a Command Line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

3.2.2 Command Line Basics: Browsing the Directory Tree and Managing Files . . . . . . . . . . . . . . . . . . 52

3.3 The File System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

3.3.1 The Filesystem Hierarchy Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

3.3.2 The User’s Home Directory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

3.4 Useful Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

3.4.1 Displaying and Modifying Text Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

3.4.2 Searching for Files and within Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

3.4.3 Managing Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

3.4.4 Managing Rights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

3.4.5 Getting System Information and Logs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

3.4.6 Discovering the Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

3.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

4. Installing Kali Linux 65

4.1 Minimal Installation Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

4.2 Step by Step Installation on a Hard Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

4.2.1 Plain Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Booting and Starting the Installer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Selecting the Language . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Selecting the Country . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Selecting the Keyboard Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Detecting Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Loading Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Detecting Network Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Configuring the Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Root Password . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

Configuring the Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

Detecting Disks and Other Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

Partitioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

Copying the Live Image . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Configuring the Package Manager (apt) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Installing the GRUB Boot Loader . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

Finishing the Installation and Rebooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

4.2.2 Installation on a Fully Encrypted File System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Introduction to LVM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Introduction to LUKS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Setting Up Encrypted Partitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

End of the Guided Partitioning with Encrypted LVM . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

4.3 Unattended Installations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

4.3.1 Preseeding Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

With Boot Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

With a Preseed File in the Initrd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

With a Preseed File in the Boot Media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

With a Preseed File Loaded from the Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

4.3.2 Creating a Preseed File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

4.4 ARM Installations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

4.5 Troubleshooting Installations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

4.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

5. Configuring Kali Linux 103

5.1 Configuring the Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

5.1.1 On the Desktop with NetworkManager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

5.1.2 On the Command Line with Ifupdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

5.1.3 On the Command Line with systemd-networkd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

5.2 Managing Unix Users and Unix Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

5.2.1 Creating User Accounts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

5.2.2 Modifying an Existing Account or Password . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

5.2.3 Disabling an Account . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

5.2.4 Managing Unix Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

5.3 Configuring Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

5.3.1 Configuring a Specific Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

5.3.2 Configuring SSH for Remote Logins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

5.3.3 Configuring PostgreSQL Databases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

Connection Type and Client Authentication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

Creating Users and Databases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

Managing PostgreSQL Clusters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

5.3.4 Configuring Apache . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

Configuring Virtual Hosts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

Common Directives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

5.4 Managing Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

5.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

6. Helping Yourself and Getting Help 123

6.1 Documentation Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

6.1.1 Manual Pages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

6.1.2 Info Documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

6.1.3 Package-Specific Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

6.1.4 Websites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

6.1.5 Kali Documentation at docs.kali.org . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

6.2 Kali Linux Communities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

6.2.1 Web Forums on forums.kali.org . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

6.2.2 #kali-linux IRC Channel on Freenode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

6.3 Filing a Good Bug Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

6.3.1 Generic Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

How to Communicate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

What to Put in the Bug Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

Miscellaneous Tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

6.3.2 Where to File a Bug Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

6.3.3 How to File a Bug Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

Filing a Bug Report in Kali . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

Filing a Bug Report in Debian . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

Filing a Bug Report in another Free Software Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

6.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146

7. Securing and Monitoring Kali Linux 149

7.1 Defining a Security Policy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150

7.2 Possible Security Measures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152

7.2.1 On a Server . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152

7.2.2 On a Laptop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152

7.3 Securing Network Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

7.4 Firewall or Packet Filtering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

7.4.1 Netfilter Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

7.4.2 Syntax of iptables and ip6tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157

Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157

Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157

7.4.3 Creating Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

7.4.4 Installing the Rules at Each Boot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

7.5 Monitoring and Logging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

7.5.1 Monitoring Logs with logcheck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

7.5.2 Monitoring Activity in Real Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162

7.5.3 Detecting Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162

Auditing Packages with dpkg --verify . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162

Monitoring Files: AIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

7.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

8. Debian Package Management 169

8.1 Introduction to APT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170

8.1.1 Relationship between APT and dpkg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170

8.1.2 Understanding the sources.list File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172

8.1.3 Kali Repositories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173

The Kali-Rolling Repository . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173

The Kali-Dev Repository . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174

The Kali-Bleeding-Edge Repository . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174

The Kali Linux Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174

8.2 Basic Package Interaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175

8.2.1 Initializing APT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176

8.2.2 Installing Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176

Installing Packages with dpkg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176

Installing Packages with APT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177

8.2.3 Upgrading Kali Linux . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179

8.2.4 Removing and Purging Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180

8.2.5 Inspecting Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181

Querying dpkg’s Database and Inspecting .deb Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181

Querying the Database of Available Packages with apt-cache and apt . . . . . . . . . . . . . . . . . . . . 185

8.2.6 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187

Handling Problems after an Upgrade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187

The dpkg Log File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188

Reinstalling Packages with apt --reinstall and aptitude reinstall . . . . . . . . . . . . . . . . . . . 189

Leveraging --force-* to Repair Broken Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189

8.2.7 Frontends: aptitude and synaptic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190

Aptitude . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190

Synaptic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194

8.3 Advanced APT Configuration and Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194

8.3.1 Configuring APT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195

8.3.2 Managing Package Priorities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196

8.3.3 Working with Several Distributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198

8.3.4 Tracking Automatically Installed Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199

8.3.5 Leveraging Multi-Arch Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200

Enabling Multi-Arch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200

Multi-Arch Related Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201

8.3.6 Validating Package Authenticity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202

8.4 Package Reference: Digging Deeper into the Debian Package System . . . . . . . . . . . . . . . . 204

8.4.1 The control File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206

Dependencies: the Depends Field . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207

Pre-Depends, a More Demanding Depends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207

Recommends, Suggests, and Enhances Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208

Conflicts: the Conflicts Field . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208

Incompatibilities: the Breaks Field . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209

Provided Items: the Provides Field . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209

Replacing Files: The Replaces Field . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210

8.4.2 Configuration Scripts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

Installation and Upgrade Script Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213

Package Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214

8.4.3 Checksums, Conffiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214

8.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216

9. Advanced Usage 221

9.1 Modifying Kali Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222

9.1.1 Getting the Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223

9.1.2 Installing Build Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226

9.1.3 Making Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226

Applying a Patch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227

Tweaking Build Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229

Packaging a New Upstream Version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229

9.1.4 Starting the Build . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231

9.2 Recompiling the Linux Kernel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233

9.2.1 Introduction and Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233

9.2.2 Getting the Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234

9.2.3 Configuring the Kernel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235

9.2.4 Compiling and Building the Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236

9.3 Building Custom Kali Live ISO Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237

9.3.1 Installing Pre-Requisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237

9.3.2 Building Live Images with Different Desktop Environments . . . . . . . . . . . . . . . . . . . . . . . . . 238

9.3.3 Changing the Set of Installed Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238

9.3.4 Using Hooks to Tweak the Contents of the Image . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239

9.3.5 Adding Files in the ISO Image or in the Live Filesystem . . . . . . . . . . . . . . . . . . . . . . . . . . . 240

9.4 Adding Persistence to the Live ISO with a USB Key . . . . . . . . . . . . . . . . . . . . . . . . . . . 240

9.4.1 The Persistence Feature: Explanations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240

9.4.2 Setting Up Unencrypted Persistence on a USB Key . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242

9.4.3 Setting Up Encrypted Persistence on a USB Key . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243

9.4.4 Using Multiple Persistence Stores . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244

9.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246

9.5.1 Summary Tips for Modifying Kali Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246

9.5.2 Summary Tips for Recompiling the Linux Kernel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247

9.5.3 Summary Tips for Building Custom Kali Live ISO Images . . . . . . . . . . . . . . . . . . . . . . . . . . 248

10. Kali Linux in the Enterprise 251

10.1 Installing Kali Linux Over the Network (PXE Boot) . . . . . . . . . . . . . . . . . . . . . . . . . . 252

10.2 Leveraging Configuration Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255

10.2.1 Setting Up SaltStack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255

10.2.2 Executing Commands on Minions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256

10.2.3 Salt States and Other Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258

10.3 Extending and Customizing Kali Linux . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262

10.3.1 Forking Kali Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262

10.3.2 Creating Configuration Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263

10.3.3 Creating a Package Repository for APT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269

10.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273

11. Introduction to Security Assessments 279

11.1 Kali Linux in an Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281

11.2 Types of Assessments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283

11.2.1 Vulnerability Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284

Likelihood of Occurrence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287

Impact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287

Overall Risk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287

In Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288

11.2.2 Compliance Penetration Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288

11.2.3 Traditional Penetration Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289

11.2.4 Application Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291

11.3 Formalization of the Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293

11.4 Types of Attacks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294

11.4.1 Denial of Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295

11.4.2 Memory Corruption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295

11.4.3 Web Vulnerabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296

11.4.4 Password Attacks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296

11.4.5 Client-Side Attacks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297

11.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297

12. Conclusion: The Road Ahead 301

12.1 Keeping Up with Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302

12.2 Showing Off Your Newly Gained Knowledge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302

12.3 Going Further . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302

12.3.1 Towards System Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303

12.3.2 Towards Penetration Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303

Index 304

Bookscreen

Introduction

.Kali Linux is the world’s most powerful and popular penetration testing platform, used by security

professionals in a wide range of specializations, including penetration testing, forensics, reverse

engineering, and vulnerability assessment. It is the culmination of years of refinement and the

result of a continuous evolution of the platform, from WHoppiX to WHAX, to BackTrack, and now

to a complete penetration testing framework leveraging many features of Debian GNU/Linux and

the vibrant open source community worldwide.

Kali Linux has not been built to be a simple collection of tools, but rather a flexible framework

that professional penetration testers, security enthusiasts, students, and amateurs can customize

to fit their specific needs.

Why This Book?

Kali Linux is not merely a collection of various information security tools that are installed on a

standard Debian base and preconfigured to get you up and running right away. To get the most

out of Kali, it is important to have a thorough understanding of its powerful Debian GNU/Linux

underpinnings (which support all those great tools) and learning how you can put them to use in

your environment.

Although Kali is decidedly multi-purpose, it is primarily designed to aid in penetration testing.

The objective of this book is not only to help you feel at home when you use Kali Linux, but also to

help improve your understanding and streamline your experience so that when you are engaged

in a penetration test and time is of the essence, you won’t need to worry about losing precious

minutes to install new software or enable a new network service. In this book, we will introduce

you first to Linux, then we will dive deeper as we introduce you to the nuances specific to Kali

Linux so you know exactly what is going on under the hood.

This is invaluable knowledge to have, particularly when you are trying to work under tight time

constraints. It is not uncommon to require this depth of knowledge when you are getting set up,

troubleshooting a problem, struggling to bend a tool to your will, parsing output from a tool, or

leveraging Kali in a larger-scale environment.

Is This Book for You?

If you are eager to dive into the intellectually rich and incredibly fascinating field of information

security, and have rightfully selected Kali Linux as a primary platform, then this book will help

you in that journey. This book is written to help first-time Linux users, as well as current Kali

users seeking to deepen their knowledge about the underpinnings of Kali, as well as those who

have used Kali for years but who are looking to formalize their learning, expand their use of Kali,

and fill in gaps in their knowledge.

In addition, this book can serve as a roadmap, technical reference, and study guide for those pursuing

the Kali Linux Certified Professional certification.