Network Security Cheatsheet

The world of cybersecurity is built on frameworks and models that ensure standardized, secure communication between computer systems. At the heart of these models is the OSI Model (Open Systems Interconnection) and the TCP/IP Model — cornerstones of modern networking. These frameworks outline how data travels from one computer to another, identifying potential vulnerabilities at each step.

As a network analyst, understanding these models and the associated attacks, penetration testing strategies, and defensive security measures is essential for building resilient systems. This cheatsheet provides an in-depth look at the OSI Model, common network layer attacks, and how to secure each layer effectively.

Understanding the OSI Model

The OSI Model, established by the International Organization for Standardization (ISO) in the 1980s, consists of seven layers. Each layer represents a specific aspect of communication and operates independently while working collaboratively with the others. These layers are:

1. Physical Layer

• Purpose: Responsible for transmitting raw binary data (0s and 1s) over physical mediums like cables or wireless connections.
• Key Components: Ethernet cables, switches, hubs, and wireless standards (e.g., Wi-Fi).