Introduction
Securing a PHP website is critical to protect data, users, and functionality. Many websites get hacked due to weak validation, poor password handling, insecure sessions, and unprotected database operations. This guide provides practical, hands-on steps to secure your PHP site using modern techniques while maintaining functionality.
Step One: Input Validation
Always validate and sanitize every user input. Do not trust GET, POST, or COOKIE values directly. Use built-in PHP functions like `filter_var()`, `htmlspecialchars()`, and regex checks. Example:
$name = htmlspecialchars($_POST['name']);
$email = filter_var($_POST['email'], FILTER_VALIDATE_EMAIL);
Step Two: Secure Passwords
Never store passwords as plain text. Always use `password_hash()` for creating passwords and `password_verify()` for login. Example:
$hashed = password_hash($password, PASSWORD_DEFAULT);
if(password_verify($input_password, $hashed)){
// Login successful
}
Step Three: Session Management
Use sessions securely to track logged-in users. Regenerate session IDs after login. Set proper session cookie parameters. Avoid storing sensitive data directly in session variables.
session_start();
session_regenerate_id(true);
$_SESSION['user'] = $user_id;
Step Four: Database Security
Use prepared statements for all database queries. Avoid dynamic queries with user input directly. This prevents SQL injection attacks.
$stmt = $conn->prepare("SELECT * FROM users WHERE email=?");
$stmt->bind_param("s",$email);
$stmt->execute();
Step Five: Prevent CSRF
Use nonces or tokens for form submissions to prevent Cross-Site Request Forgery attacks.
<?php
$token = bin2hex(random_bytes(32));
$_SESSION['csrf_token'] = $token;
?>
<input type="hidden" name="csrf_token" value="<?php echo $token; ?>">
Step Six: Prevent XSS
Escape all outputs when displaying user data. This prevents Cross-Site Scripting attacks.
echo htmlspecialchars($user_input, ENT_QUOTES, 'UTF-8');
Step Seven: Backup and Monitoring
Regularly backup your database and files. Monitor server logs for suspicious activity. Keep PHP and all dependencies updated to latest versions to patch known vulnerabilities.