Web Application Security

Web security is the practice of protecting web applications, websites, and web services against cyber attacks. Every application accessible over the Internet is a potential target.

Scope of Web Security

Web Security vs Network Security

OWASP (Open Web Application Security Project) updates the top 10 risks of web application security every 3-4 years. This list is the gold standard of web security.

OWASP Top 10 - 2024 Current List

Let's examine the most common types of attacks against web applications in detail. Learn how each attack works and how to prevent it.

SQL Injection (SQLi)

$query = "SELECT * FROM users WHERE id = " . $_GET['id'];
// Attacker: ?id=1 OR 1=1 --

$stmt = $pdo->prepare("SELECT * FROM users WHERE id = ?");
$stmt->execute([$_GET['id']]);

Cross-Site Scripting (XSS)

echo "Merhaba " . $_GET['name'];
// Attacker: ?name=<script>alert('XSS')</script>

echo "Merhaba " . htmlspecialchars($_GET['name'], ENT_QUOTES);

Cross-Site Request Forgery (CSRF)

Other Notable Attacks

Secure coding is the foundation of your web application. The OWASP Secure Coding Practices guide identifies best practices.

10 Golden Rules of Secure Coding

Secure Coding Examples

// BAD: String concatenation
$query = "SELECT * FROM users 
WHERE username = '" . $username . "'";
$result = mysqli_query($conn, $query);

// GOOD: Prepared statement
$stmt = $pdo->prepare(
"SELECT * FROM users WHERE username = ?");
$stmt->execute([$username]);
$user = $stmt->fetch();

// BAD: Direct output
echo "Merhaba " . $_GET['name'];
// Attacker: ?name=<script>...</script>

// GOOD: Output encoding
$name = htmlspecialchars(
$_GET['name'], ENT_QUOTES, 'UTF-8');
echo "Merhaba " . $name;

HTTP security headers tell the browser about the application's security policies. It is a simple but effective layer of defense.

Mandatory Security Headings

Security Hood Testing Tools

Security tests detect vulnerabilities before they go live. Different types of testing are applied at different stages.

Test Types

Security Testing Process

Automatic Security Scanning

Web Application Firewall (WAF) protects your web application from malicious traffic. Strengthen your defense with security tools.

What is WAF?

WAF Types

Recommended Security Tools

Use this comprehensive checklist to evaluate your website's security.