What are some best practices for scanning and monitoring PHP files for potential security threats?

One best practice for scanning and monitoring PHP files for potential security threats is to regularly scan your codebase using security tools like PHP CodeSniffer or PHPStan. Additionally, implementing input validation and output escaping can help prevent common security vulnerabilities like SQL injection and cross-site scripting attacks. Lastly, keeping your PHP version up to date and following secure coding practices can further enhance the security of your application.

// Example of input validation and output escaping in PHP
$input = $_POST['input'];
$clean_input = filter_var($input, FILTER_SANITIZE_STRING);

// Example of using prepared statements to prevent SQL injection
$stmt = $pdo->prepare('SELECT * FROM users WHERE username = :username');
$stmt->bindParam(':username', $clean_input);
$stmt->execute();