What are some best practices for handling user input in PHP to prevent vulnerabilities like injection attacks?

To prevent vulnerabilities like injection attacks in PHP, it is crucial to sanitize and validate user input before using it in any database queries or other sensitive operations. One common best practice is to use prepared statements with parameterized queries when interacting with a database, as this helps prevent SQL injection attacks. Additionally, you can use functions like htmlspecialchars() and filter_var() to sanitize input and ensure it meets expected criteria. 

// Example of using prepared statements to prevent SQL injection
$pdo = new PDO('mysql:host=localhost;dbname=mydatabase', 'username', 'password');
$stmt = $pdo->prepare('SELECT * FROM users WHERE username = :username');
$stmt->bindParam(':username', $_POST['username']);
$stmt->execute();
$results = $stmt->fetchAll();

// Example of sanitizing input using htmlspecialchars()
$cleanInput = htmlspecialchars($_POST['input']);

// Example of validating input using filter_var()
$cleanEmail = filter_var($_POST['email'], FILTER_VALIDATE_EMAIL);

Keywords

SQL injection XSS htmlentities prepared statements input validation

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