List of Figures
List of Tables
Glossary
1 Introduction
 1.1 Purpose of This Book
  1.1.1 History
  1.1.2 Audience
  1.1.3 This is NOT a Textbook
 1.2 Using This Book
  1.2.1 Organisation of the Chapters
  1.2.2 Following the Examples
  1.2.3 Terminology and Notation
  1.2.4 Book Website and Formats
  1.2.5 Downloading Example Files
  1.2.6 Other Books and Sources
 1.3 Recognition
  1.3.1 Acknowledgements
  1.3.2 Apologies, Limitations and Reporting Bugs
  1.3.3 Licensing
2 Linux, Ubuntu and VirtualBox
 2.1 What is Ubuntu Linux?
  2.1.1 Why Not Microsoft Windows?
 2.2 Installing Ubuntu Linux
  2.2.1 Ubuntu Variants
  2.2.2 Installation Approaches
 2.3 Virtualisation and VirtualBox
3 Virtual Networking with Linux and VirtualBox
 3.1 Virtual Networking and virtnet
  3.1.1 What is Virtual Networking?
  3.1.2 Motivation for virtnet
  3.1.3 How Does virtnet Work?
  3.1.4 virtnet Terminology
  3.1.5 History of virtnet
 3.2 Getting Started
  3.2.1 General Requirements
  3.2.2 Installation
  3.2.3 Creating Your First Topology
  3.2.4 Creating a Different Topology
 3.3 Using virtnet
  3.3.1 Usernames and Passwords
  3.3.2 Login to Nodes with VirtualBox
  3.3.3 Login to Nodes with Secure Shell
  3.3.4 Transferring Files
  3.3.5 Using the Host Web Browser to Access a Guest Web Server
  3.3.6 Shutting Down, Saving and Deleting Nodes
 3.4 Troubleshooting virtnet
4 Linux Command Line
 4.1 Prerequisites
  4.1.1 Assumed Knowledge
  4.1.2 Linux and Network Setup
 4.2 Entering Commands
  4.2.1 Command Prompt
  4.2.2 Commands, Parameters and Options
  4.2.3 Output and Errors
  4.2.4 Help with Commands
 4.3 Directory and File Operations
 4.4 Viewing and Editing Files
  4.4.1 Viewing Text Files
  4.4.2 Creating Text Files
  4.4.3 Text Editors
 4.5 Shortcuts in Bash
 4.6 Pipes and Redirection
 4.7 Processes and Jobs
 4.8 Searching for Files
 4.9 Processing Text Files
 4.10 More Examples
5 The Internet and Applications
 5.1 The Internet
 5.2 Clients, Servers and Addressing
  5.2.1 Addresses and Ports
  5.2.2 Servers
  5.2.3 Clients
 5.3 Web Browsing
  5.3.1 HTTP Operation
  5.3.2 Web Browsing on the Command Line
 5.4 Remote Login
6 Automating Tasks with Scripts
 6.1 Prerequisites
  6.1.1 Assumed Knowledge
  6.1.2 Linux and Network Setup
 6.2 Introduction to Scripts
  6.2.1 Shell Scripts are Text Files
  6.2.2 Variables in Scripts
  6.2.3 For Loops
  6.2.4 If/Then/Else
  6.2.5 Input Parameters
  6.2.6 Executing Shell Scripts
 6.3 More Scripting Examples
  6.3.1 First Script with echo and ls
  6.3.2 Using Variables
  6.3.3 For Loops
  6.3.4 If/Then/Else
  6.3.5 Input Arguments
  6.3.6 Reading a Text File
  6.3.7 Extra Commands
7 Users and Permissions
 7.1 Prerequisites
  7.1.1 Assumed Knowledge
  7.1.2 Linux and Network Setup
 7.2 Users and Permissions in Linux
  7.2.1 Users
  7.2.2 Logins
  7.2.3 Passwords
  7.2.4 Permissions
 7.3 Commands for Managing Users and Permissions
 7.4 Users and Permissions by Example
  7.4.1 Adding Users
  7.4.2 /etc/passwd and /etc/shadow Files
  7.4.3 Adding Groups
  7.4.4 Creating Files and Directories
  7.4.5 Setting Permissions
  7.4.6 Summary and Other Issues
 7.5 Passwords, Hashes and Rainbow Tables
  7.5.1 Storing Actual Passwords
  7.5.2 Storing Hashed Passwords
  7.5.3 Brute Force Attacks on Hashed Passwords
  7.5.4 Pre-calculated Hashes and Rainbow Tables
  7.5.5 Salting a Password
  7.5.6 Summary and Other Issues
8 Cryptography in Linux
 8.1 Prerequisites
  8.1.1 Assumed Knowledge
  8.1.2 Linux and Network Setup
 8.2 OpenSSL
  8.2.1 Overview of OpenSSL
  8.2.2 Example Scenario
  8.2.3 Random Numbers
  8.2.4 Symmetric Key Encryption Basics
  8.2.5 Hash and MAC Functions
  8.2.6 Symmetric Key Encryption Padding and Modes of Operation
  8.2.7 RSA and Digital Signatures
  8.2.8 Diffie-Hellman Secret Key Exchange
  8.2.9 Performance Benchmarking
 8.3 Using Classical Ciphers with pycipher
  8.3.1 Install pycipher (Recommended Method)
  8.3.2 Install pycipher (Alternative Method)
  8.3.3 Using pycipher
9 Networking Tools
 9.1 Prerequisites
  9.1.1 Assumed Knowledge
  9.1.2 Linux and Network Setup
 9.2 Operating Systems and Tool Interfaces
 9.3 Viewing and Changing Network Interface Information
  9.3.1 Viewing Interface Information
  9.3.2 Changing Interface Information
 9.4 Viewing Ethernet Interface Details
 9.5 Testing Network Connectivity
 9.6 Testing a Route
 9.7 Converting Between Domain Names and IP Addresses
 9.8 Viewing the Routing Table
 9.9 Converting IP Addresses to Hardware Addresses
 9.10 Network Statistics
 9.11 Useful Networking Files
  9.11.1 /etc/hostname
  9.11.2 /etc/hosts
  9.11.3 /etc/resolv.conf
  9.11.4 /etc/network/interfaces
  9.11.5 /etc/services
  9.11.6 /etc/protocols
  9.11.7 /etc/sysctl.conf
 9.12 Application and Performance Testing
  9.12.1 Generic Application Testing with netcat
  9.12.2 Traffic Monitoring with iptraf
  9.12.3 Internet Performance Measurements with iperf
  9.12.4 Packet Drops and Delays with tc
10 Routing in Linux
 10.1 Prerequisites
  10.1.1 Assumed Knowledge
  10.1.2 Linux and Network Setup
 10.2 Routers
  10.2.1 Routers and Hosts
  10.2.2 Enabling Routing
  10.2.3 Editing the Routing Table
 10.3 Networking Setup Example
  10.3.1 Prerequisites
  10.3.2 Setting IP Addresses
  10.3.3 Enable Forwarding
  10.3.4 Add Routes
  10.3.5 Testing the Internet
11 Packet Capture
 11.1 Prerequisites
  11.1.1 Assumed Knowledge
  11.1.2 Linux and Network Setup
 11.2 Packet Capture Concepts
 11.3 Capturing and Filtering with tcpdump
  11.3.1 Capturing with tcpdump
  11.3.2 Filtering Packets with tcpdump
 11.4 Viewing and Analysing Packets with Wireshark
  11.4.1 Viewing Captured Traffic
  11.4.2 Analysis and Statistics
  11.4.3 Filters
 11.5 Capture Examples
  11.5.1 Ping and ICMP
  11.5.2 Web Browsing and HTTP
  11.5.3 Netcat with TCP and UDP
  11.5.4 Web Browsing to sandilands.info
  11.5.5 Ping with Fragmented IP Datagrams
  11.5.6 Tracepath with UDP and ICMP
12 Web Server with Apache
 12.1 Prerequisites
  12.1.1 Assumed Knowledge
  12.1.2 Linux and Network Setup
 12.2 Installing and Running Apache Web Server
  12.2.1 Installing the Web Server
  12.2.2 Important Files
  12.2.3 Testing the Web Server
  12.2.4 Creating Fake Domain Names
  12.2.5 Managing the Web Server
  12.2.6 Viewing Log Files
 12.3 HTTPS and Certificates
  12.3.1 HTTPS Step 1: Create a Certificate Authority
  12.3.2 HTTPS Step 2: Create a Certificate for our Web Server
  12.3.3 HTTPS Step 3: Enable HTTPS in Apache
  12.3.4 HTTPS Step 4: Load the CA Certificate in the Client
  12.3.5 Testing our Web Server
13 Firewalls with iptables
 13.1 Prerequisites
  13.1.1 Assumed Knowledge
  13.1.2 Linux and Network Setup
 13.2 Firewall Concepts
  13.2.1 How Do Firewalls Work?
  13.2.2 Firewall Rules
  13.2.3 Firewalls and Servers
 13.3 iptables Concepts
  13.3.1 Chains in iptables
  13.3.2 Rules in iptables
 13.4 General Examples of iptables
  13.4.1 Example Network
  13.4.2 Host-Based Firewall
  13.4.3 Prevent Ping From Working
  13.4.4 View Current Rules
  13.4.5 Delete All Rules
  13.4.6 Router-Based Firewall
  13.4.7 Prevent External Hosts Accessing to SSH Server
  13.4.8 Block Computer from Accessing External Web Servers
  13.4.9 Changing the Default Policy
  13.4.10 Allow Access to a Web Server
 13.5 Stateful Packet Inspection Concept and Examples
  13.5.1 SPI Concepts
  13.5.2 SPI Example in iptables
14 DHCP Server for Automatic IP Addresses
 14.1 Prerequisites
  14.1.1 Assumed Knowledge
  14.1.2 Linux and Network Setup
 14.2 Automatic IP Address Configuration
 14.3 Installing a DHCP Server
  14.3.1 Install ISC DHCP Server
  14.3.2 Configure DHCP Server
  14.3.3 Restart the DHCP Server
 14.4 Using a DHCP Client
 14.5 Monitoring a DHCP Server
 14.6 More Resources on DHCP
15 Distributed Version Control with git
 15.1 Prerequisites
  15.1.1 Assumed Knowledge
  15.1.2 Linux and Network Setup
 15.2 Version Control Concepts
 15.3 Setup a Git Repository
  15.3.1 Example Scenario
  15.3.2 Setup the Repositories on Server
 15.4 Using Git
  15.4.1 Clone an Existing Repository
  15.4.2 Configure the Git Client
  15.4.3 Common Git Operations
16 Attacks on Web Applications
 16.1 Prerequisites
  16.1.1 Assumed Knowledge
  16.1.2 Linux and Network Setup
 16.2 Setup Demonstration Web Sites
  16.2.1 Network Topology
  16.2.2 Deploy the Web Sites
  16.2.3 Domain Names
  16.2.4 Setup Web Browsers
 16.3 MyUni Grading Website
  16.3.1 Access the Website
  16.3.2 Users
  16.3.3 Login System
  16.3.4 Subjects and Grades
  16.3.5 Desired Security Policy
  16.3.6 Adding New Users and Subjects
 16.4 Cookie Stealing Attack
 16.5 Unvalidated Redirect Attack
 16.6 SQL Injection Attack
 16.7 CSRF Attack
 16.8 Next Steps
17 Denial of Service Attacks
 17.1 Prerequisites
  17.1.1 Assumed Knowledge
  17.1.2 Linux and Network Setup
 17.2 Address Spoofing
  17.2.1 Ping Without Address Spoofing
  17.2.2 Fake Source Address is Non-Existent Node
  17.2.3 Fake Source Address is Another Node on LAN
 17.3 Ping Flooding DoS Attack
  17.3.1 Setup Nodes and Links: sysctl and tc
  17.3.2 Using a Fake Source Address: iptables
  17.3.3 Ping to Entire Subnet using Directed Broadcast
  17.3.4 Capturing Traffic and Viewing Statistics: tcpdump and iptraf
  17.3.5 Pinging Multiple Destinations with a Shell Script
  17.3.6 Denial of Service on a Web Server
  17.3.7 Closing Notes
 17.4 NTP DDoS Attack
  17.4.1 Assumptions
  17.4.2 Setup NTP Servers
  17.4.3 Test NTP Servers
  17.4.4 Requesting the Monitoring Data
  17.4.5 Basic NTP DoS Attack
  17.4.6 NTP DDoS Attack
  17.4.7 Next Steps
18 Private Networking with OpenVPN and Tor
19 Custom Applications with Sockets
 19.1 Prerequisites
  19.1.1 Assumed Knowledge
  19.1.2 Linux and Network Setup
 19.2 Programming with Sockets
  19.2.1 Servers Handling Multiple Connections
  19.2.2 Further Explanation
 19.3 TCP Sockets in C
  19.3.1 Example Usage
  19.3.2 TCP Client
  19.3.3 TCP Server
 19.4 UDP Sockets in C
  19.4.1 Example Usage
  19.4.2 UDP Client
  19.4.3 UDP Server
 19.5 TCP Sockets in Python
  19.5.1 Example Usage
  19.5.2 TCP Client
  19.5.3 TCP Server
 19.6 UDP Sockets in Python
  19.6.1 Example Usage
  19.6.2 UDP Client
  19.6.3 UDP Server
 19.7 Raw Sockets in Python
20 Wireless Security in Linux
 20.1 Prerequisites
  20.1.1 Assumed Knowledge
  20.1.2 Linux and Network Setup
 20.2 Wireless LANs
  20.2.1 Wireless LAN Concepts
  20.2.2 Linux
  20.2.3 macOS
  20.2.4 Windows
 20.3 Capturing Wireless LAN Packets in Monitor Mode with iw
  20.3.1 Getting Started with iw
  20.3.2 Capturing in Monitor Mode
  20.3.3 What Can Go Wrong?
 20.4 Decrypting Captured Wireless LAN Packets
A Packet Formats and Constants
 A.1 Packet Formats
 A.2 Port Numbers and Status Codes
B Statistics for Communications and Security
 B.1 Binary Values
 B.2 Counting
 B.3 Permutations and Combinations
 B.4 Probability
 B.5 Collisions
C Cryptography Assumptions and Principles
 C.1 Assumptions
  C.1.1 Encryption
  C.1.2 Knowledge of Attacker
  C.1.3 Authentication with Symmetric Key and MACs
  C.1.4 Hash Functions
  C.1.5 Digital Signatures
  C.1.6 Key Management and Random Numbers
 C.2 Principles
D Versions of this Book