What security measures should be taken when processing user input in PHP?

When processing user input in PHP, it is important to implement security measures to prevent common vulnerabilities such as SQL injection, cross-site scripting (XSS), and cross-site request forgery (CSRF). To enhance security, you should always validate and sanitize user input, use prepared statements for database queries, and utilize functions like htmlspecialchars() to prevent XSS attacks. 

// Example of sanitizing user input in PHP
$userInput = $_POST['user_input'];
$cleanInput = htmlspecialchars(strip_tags(trim($userInput));

// Example of using prepared statements for database queries
$stmt = $pdo->prepare('SELECT * FROM users WHERE username = :username');
$stmt->execute(['username' => $cleanInput]);

// Example of preventing XSS attacks by encoding user input
echo 'Welcome ' . htmlspecialchars($cleanInput);

Keywords

SQL injection Cross-site scripting (XSS) Input validation Escaping user input Prepared statements

Related Questions