Linux Basics for Hackers: Getting Started with Networking, Scripting, and Security in Kali

by OccupyTheWeb

Overview

This practical, tutorial-style book uses the Kali Linux distribution to teach Linux basics with a focus on how hackers would use them. Topics include Linux command line basics, filesystems, networking, BASH basics, package management, logging, and the Linux kernel and drivers.

Many aspiring hackers are unfamiliar with Linux, having learned computer basics in a Windows or Mac environment. This can pose the single most important obstacle to mastering the skills to becoming a better hacker; while hacking can be done with Windows or OS X, nearly all hacking tools are developed specifically for Linux.

Linux Basics for Hackers aims to provide you with a foundation of Linux skills that every hacker needs. You'll learn the advantages of Linux over other operating systems for hacking purposes, then move into the brass tacks: command line basics, filesystems, networking, bash, package management, compressing and archiving, process management, logging, device storage, and the Linux kernel. This comprehensive guide also addresses MySQL and postgresql (the database system Metasploit runs on) and some Python scripting. As you progress, you'll have access to numerous real-world examples and hands-on exercises to apply your new knowledge and bring yourself up to speed.

Product Details

ISBN-13:	9781593278564
Publisher:	No Starch Press
Publication date:	12/04/2018
Sold by:	Penguin Random House Publisher Services
Format:	eBook
Pages:	248
File size:	20 MB
Note:	This product may take a few minutes to download.

About the Author

OccupyTheWeb is an infosec consultant, forensic investigator, and trainer with over 20 years in the industry. He formerly wrote the Null Byte column on www.wonderhowto.com, and presently runs www.hackers-arise.com. In addition, he trains the U.S. military, Department of Defense contractors, and federal employees in information security and hacking.

Table of Contents

Acknowledgments xix

Introduction xxi

What's in This Book xxii

What Is Ethical Hacking? xxiii

Penetration Testing xxiii

Military and Espionage xxiii

Why Hackers Use Linux xxiv

Linux Is Open Source xxiv

Linux Is Transparent xxiv

Linux Offers Granular Control xxiv

Most Hacking Tools Are Written for Linux xxiv

The Future Belongs to Linux/Unix xxiv

Downloading Kali Linux xxv

Virtual Machines xxvi

Installing VirtualBox xxvi

Setting Up Your Virtual Machine xxvii

Installing Kali on the VM xxix

Setting Up Kali xxxi

1 Getting Started With The Basics 1

Introductory Terms and Concepts 1

A Tour of Kali 3

The Terminal 4

The Linux Filesystem 4

Basic Commands in Linux 5

Finding Yourself with pwd 6

Checking Your Login with whoami 6

Navigating the Linux Filesystem 6

Getting Help 8

Referencing Manual Pages with man 9

Finding Stuff 9

Searching with locate 10

Finding Binaries with whereis 10

Finding Binaries in the PATH Variable with which 10

Performing More Powerful Searches with find 11

Filtering with grep 12

Modifying Files and Directories 13

Creating Files 13

Creating a Directory 15

Copying a File 15

Renaming a File 15

Removing a File 16

Removing a Directory 16

Go Play Now! 17

Exercises 17

2 Text Manipulation 19

Viewing Files 20

Taking the Head 20

Grabbing Thai Tail 21

Numbering the Lines 22

Filtering Text with grep 22

Hacker Challenge: Using grep, nl, tail, and head 23

Using sed to Find and Replace 23

Viewing Files with more and less 24

Controlling the Display with more 25

Displaying and Filtering with less 25

Summary 26

Exercises 27

3 Analyzing And Managing Networks 29

Analyzing Networks with ifconfig 29

Checking Wireless Network Devices with iwconfig 30

Changing Your Network Information 31

Changing Your IP Address 31

Changing Your Network Mask and Broadcast Address 32

Spoofing Your MAC Address 32

Assigning New IP Addresses from the DHCP Server 32

Manipulating the Domain Name System 33

Examining DNS with dig 33

Changing Your DNS Server 34

Mapping Your Own IP Addresses 36

Summary 37

Exercises 37

4 Adding And Removing Software 39

Using apt to Handle Software 40

Searching for a Package 40

Adding Software 40

Removing Software 41

Updating Packages 42

Upgrading Packages 42

Adding Repositories to Your sources.list File 43

Using a GUI-based Installer 45

Installing Software with git 46

Summary 47

Exercises 47

5 Controlling File And Directory Permissions 49

Different Types of Users 50

Granting Permissions 50

Granting Ownership to an Individual User 50

Granting Ownership to a Group 51

Checking Permissions 51

Changing Permissions 52

Changing Permissions with Decimal Notation 52

Changing Permissions with UGO 54

Giving Root Execute Permission on a New Tool 55

Setting More Secure Default Permissions with Masks 56

Special Permissions 57

Granting Temporary Root Permissions with SUID 57

Granting the Root User's Group Permissions SGID 58

The Outmoded Sticky Bit 58

Special Permissions, Privilege Escalation, and the Hacker 58

Summary 60

Exercises 60

6 Process Management 61

Viewing Processes 62

Filtering by Process Name 63

Finding the Greediest Processes with top 64

Managing Processes 64

Changing Process Priority with nice 65

Killing Processes 66

Running Processes in the Background 68

Moving a Process to the Foreground 68

Scheduling Processes 69

Summary 70

Exercises 70

7 Managing User Environment Variables 71

Viewing and Modifying Environment Variables 72

Viewing All Environment Variables 72

Filtering for Particular Variables 73

Changing Variable Values for a Session 73

Making Variable Value Changes Permanent 74

Changing Your Shell Prompt 75

Changing Your PATH 76

Adding to the PATH Variable 76

How Not to Add to the PATH Variable 77

Creating a User-Defined Variable 77

Summary 78

Exercises 79

8 Bash Scripting 81

A Crash Course in Bash 82

Your First Script: "Hello, Hackers-Arisel" 82

Setting Execute Permissions 83

Running HelloHockersArise 84

Adding Functionality with Variables and User Input 84

Your Very First Hacker Script: Scan for Open Ports 86

Our Task 86

A Simple Scanner 87

Improving the MySQL Scanner 88

Common Built-in Bash Commands 90

Summary 91

Exercises 91

9 Compressing And Archiving 93

What Is Compression? 93

Tarring Files Together 94

Compressing Files 96

Compressing with gzip 96

Compressing with bzip2 97

Compressing with compress 97

Creating Bit-by-Bit or Physical Copies of Storage Devices 98

Summary 99

Exercises 99

10 Filesystem And Storage Device Management 101

The Device Directory /dev 102

How Linux Represents Storage Devices 103

Drive Partitions 103

Character and Block Devices 105

List Block Devices and Information with Isblk 105

Mounting and Unmounting 106

Mounting Storage Devices Yourself 106

Unmounting with umount 107

Monitoring Filesystems 107

Getting Information on Mounted Disks 107

Checking for Errors 108

Summary 109

Exercises 109

11 The Logging System 111

The rsyslog Logging Daemon 112

The rsyslog Configuration File 112

The rsyslog Logging Rules 113

Automatically Cleaning Up Logs with logrotate 115

Remaining Stealthy 117

Removing Evidence 117

Disabling Logging 118

Summary 119

Exercises 119

12 Using And Abusing Services 121

Starting, Stopping, and Restarting Services 122

Creating an HTTP Web Server with the Apache Web Server 122

Starting with Apache 123

Editing the index.html File 124

Adding Some HTML 124

Seeing What Happens 125

OpenSSH and the Raspberry Spy Pi 125

Setting Up the Raspberry Pi 126

Building the Raspberry Spy Pi 126

Configuring the Camera 127

Starting to Spy 129

Extracting Information from MySQL 130

Starting MySQL 130

Interacting with MySQL 131

Setting a MySQL Password 131

Accessing a Remote Database 132

Connecting to a Database 133

Database Tables 134

Examining the Data 135

PostgreSQL with Metasploit 135

Summary 137

Exercises 138

13 Becoming Secure And Anonymous 139

How the Internet Gives Us Away 140

The Onion Router System 141

How Tor Works 141

Security Concerns 142

Proxy Servers 143

Setting Proxies in the Config Pile 144

Some More Interesting Options 146

Security Concerns 148

Virtual Private Networks 148

Encrypted Email 150

Summary 151

Exercises 151

14 Understanding And Inspecting Wireless Networks 153

Wi-Fi Networks 154

Basic Wireless Commands 154

Wi-Fi Recon with aircrack-ng 157

Detecting and Connecting to Bluetooth 159

How Bluetooth Works 160

Bluetooth Scanning and Reconnaissance 160

Summary 164

Exercises 164

15 Managing The Linux Kernel And Loadable Kernel Modules 165

What Is a Kernel Module? 166

Checking the Kernel Version 167

Kernel Tuning with sysctl 167

Managing Kernel Modules 169

Finding More Information with modinfo 170

Adding and Removing Modules with modprobe 170

Inserting and Removing a Kernel Module 171

Summary 171

Exercises 172

16 Automating Tasks With Job Scheduling 173

Scheduling an Event or Job to Run on an Automatic Basis 174

Scheduling a Backup Task 176

Using crontab to Schedule Your MySQLscanner 177

Crontab Shortcuts 178

Using rc Scripts to Run Jobs at Startup 178

Linux Runlevels 179

Adding Services to rc.d 179

Adding Services to Your Bootup via a GUI 180

Summary 181

Exercises 181

17 Python Scripting Basics For Hackers 183

Adding Python Modules 184

Using pip 184

Installing Third-Party Modules 185

Getting Started Scripting with Python 186

Variables 187

Comments 190

Functions 190

Lists 191

Modules 192

Object-Oriented Programming (OOP) 192

Network Communications in Python 194

Building a TCP Client 194

Creating a TCP Listener 195

Dictionaries, Loops, and Control Statements 197

Dictionaries 197

Control Statements 197

Loops 198

Improving Our Hacking Scripts 199

Exceptions and Password Crackers 201

Summary 203

Exercises 203

Index 205