Common Web Application Vulnerabilities Ethical Hacking

What You’ll Learn 📚

• Core concepts of web application vulnerabilities
• Key terminology in ethical hacking
• Practical examples of common vulnerabilities
• How to protect web applications from attacks
• Troubleshooting common issues

Introduction to Web Application Vulnerabilities

Web applications are everywhere, from social media platforms to online banking. Unfortunately, they can also be targets for hackers. Understanding vulnerabilities is the first step in protecting these applications.

Core Concepts

Let’s start with some core concepts:

• Vulnerability: A weakness in a system that can be exploited by a threat actor.
• Exploit: A piece of code or technique used to take advantage of a vulnerability.
• Ethical Hacking: The practice of testing systems for vulnerabilities in a legal and authorized manner.

Key Terminology

• SQL Injection: A code injection technique that might destroy your database.
• Cross-Site Scripting (XSS): A vulnerability that allows attackers to inject malicious scripts into web pages.
• Cross-Site Request Forgery (CSRF): An attack that forces an end user to execute unwanted actions on a web application.

Simple Example: SQL Injection

# A simple Python example of SQL Injection vulnerability
def login(username, password):
    query = f"SELECT * FROM users WHERE username = '{username}' AND password = '{password}'"
    # This is vulnerable to SQL Injection!
    return execute_query(query)

# Example of an attack
malicious_input = "' OR '1'='1"
login('admin', malicious_input)

💡 Lightbulb Moment: Always sanitize user inputs to prevent SQL Injection!

Progressively Complex Examples

Example 1: Cross-Site Scripting (XSS)

// Example of XSS vulnerability
function displayComment(comment) {
    document.getElementById('comments').innerHTML += `
${comment}
`;
}

// Malicious input
let maliciousComment = "";
displayComment(maliciousComment);

⚠️ Warning: Never trust user input directly in your HTML!

Example 2: Cross-Site Request Forgery (CSRF)

🔍 Note: CSRF tokens are a common way to protect against this vulnerability.

Common Questions and Answers

1. What is ethical hacking?

   Ethical hacking involves legally breaking into computers and devices to test an organization’s defenses.

2. Why is input validation important?

   Input validation prevents attackers from injecting malicious data into your application.

3. How can I protect against SQL Injection?

   Use prepared statements and parameterized queries to ensure user input is treated as data, not code.

4. What are some tools for ethical hacking?

   Popular tools include Metasploit, Burp Suite, and OWASP ZAP.

Troubleshooting Common Issues

Here are some common issues and how to troubleshoot them:

• Issue: My SQL query isn’t working.
  Solution: Check for syntax errors and ensure all inputs are properly sanitized.
• Issue: My web page is vulnerable to XSS.
  Solution: Use libraries like DOMPurify to sanitize HTML inputs.

Practice Exercises

Try these exercises to reinforce your learning:

• Find and fix an SQL Injection vulnerability in a sample application.
• Implement input validation to prevent XSS in a JavaScript application.
• Add CSRF protection to a form using tokens.

Remember, practice makes perfect! Keep experimenting and learning. You’ve got this! 🚀

Additional Resources

• OWASP Foundation – A great resource for learning about web application security.
• Hacksplaining – Interactive tutorials on web security.