Web Security Basics

1. Introduction

Web security is crucial in ensuring the safety of web applications from threats and vulnerabilities. This lesson covers the basics of web security, including common vulnerabilities and best practices for securing web applications.

2. Common Vulnerabilities

2.1 SQL Injection

SQL Injection occurs when an attacker inserts malicious SQL queries into an input field, allowing them to manipulate the database. For example:

SELECT * FROM users WHERE username = 'admin' --';

To prevent SQL Injection, always use prepared statements.

2.2 Cross-Site Scripting (XSS)

XSS allows attackers to inject scripts into webpages viewed by users. For example:

<script>alert('Hacked!')</script>

To prevent XSS, escape user inputs and use Content Security Policy (CSP).

2.3 Cross-Site Request Forgery (CSRF)

CSRF tricks the user into submitting a request without their consent. Implement anti-CSRF tokens to mitigate this risk.

3. Prevention Techniques

3.1 Input Validation

Always validate and sanitize user inputs to avoid injection attacks.

3.2 HTTPS Implementation

Use HTTPS to encrypt data in transit, protecting it from interception.

3.3 Regular Security Audits

Conduct regular security audits and penetration testing to identify vulnerabilities.

3.4 Keep Software Updated

Always keep your web application and its dependencies updated to patch known vulnerabilities.

4. Best Practices

Use strong passwords and implement multi-factor authentication.
Limit user privileges to the minimum necessary.
Implement logging and monitoring to detect suspicious activities.
Educate users about phishing and social engineering attacks.

5. FAQ

What is a web vulnerability?

A web vulnerability is a flaw or weakness in a web application that can be exploited by an attacker.

How can I secure my web application?

Implement input validation, use HTTPS, keep software updated, and conduct security audits.

What is the difference between XSS and CSRF?

XSS allows attackers to inject scripts into webpages, while CSRF tricks users into executing unwanted actions on a different website.