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Web Application Security Fundamentals

Cyber Security Mastery: From Zero to Hero

Module 6: Web Application & Wireless Security

Web applications (websites, APIs, web services) are critical attack surfaces because they are directly accessible from the internet and handle user input.

Web Architecture Review

Most web applications follow a three-tier architecture:

  1. Presentation Tier: The user interface (HTML, CSS, JavaScript).
  2. Application Tier: The server-side logic (PHP, Python, Java, Node.js) that processes input.
  3. Data Tier: The backend database (MySQL, PostgreSQL) that stores information.

Key Security Concept: Trust Boundary

Never trust any input received from the client (Presentation Tier). All data from a user's browser must be treated as hostile and validated, sanitized, and escaped on the server (Application Tier) before being processed or inserted into the database.