Security Fundamentals

1. Understanding Common Vulnerabilities

Learn to identify and mitigate common security threats such as:

• Cross-Site Scripting (XSS)
• SQL Injection
• Cross-Site Request Forgery (CSRF)
• Authentication and Authorization Bypass
• Insecure Direct Object References (IDOR)

We'll explore practical examples and provide code snippets to demonstrate these vulnerabilities and their countermeasures.

Example: XSS Vulnerability

Consider a web page that displays user-submitted content without proper sanitization:

<div>
    Welcome, <?php echo $_GET['username']; ?>!
</div>

If a malicious user submits <script>alert('XSS Attack!')</script> as the username, the script will execute in the browser of other users viewing the page.

2. Implementing Secure Authentication

Secure authentication is crucial for verifying user identities. This section covers:

• Password Hashing and Salting
• Multi-Factor Authentication (MFA)
• OAuth 2.0 and OpenID Connect
• Secure Session Management

We will guide you through implementing these features using ASP.NET Core Identity and Azure Active Directory.

Password Hashing Example (Conceptual)

// Using a secure hashing algorithm like BCrypt or Argon2
string hashedPassword = BCrypt.Net.BCrypt.HashPassword("user_password");
bool isMatch = BCrypt.Net.BCrypt.Verify("user_password", hashedPassword);

3. Authorization and Access Control

Once a user is authenticated, you need to ensure they only access resources they are permitted to. Topics include:

• Role-Based Access Control (RBAC)
• Policy-Based Access Control
• Claim-Based Authorization
• API Security and Permissions

Learn how to define roles, policies, and claims to enforce granular access control.

4. Data Protection and Encryption

Protecting sensitive data both in transit and at rest is paramount. We will cover:

• HTTPS and TLS/SSL for data in transit
• Database Encryption (e.g., Always Encrypted)
• Key Management Services
• Securely storing secrets (e.g., Azure Key Vault)

Understand when and how to apply encryption to safeguard your application's data.

5. Secure Development Lifecycle

Integrating security into every phase of development:

• Threat Modeling
• Security Code Reviews
• Automated Security Testing (SAST, DAST)
• Dependency Scanning
• Secure Deployment Practices

Adopting a secure development lifecycle (SDL) helps build security in from the start, rather than trying to bolt it on later.