Stop user enumerations for PCI scanner compliance

add_action( 'plugins_loaded', function() {

	if( ! is_user_logged_in() && isset( $_REQUEST['author'] ) ) {

		if( preg_match( '/\\d/', $_REQUEST['author'] ) > 0 ) {

			wp_die(
				esc_html__( 'forbidden - number in author name not allowed = ', 'stop-user-enumeration' )
				. esc_html( $_REQUEST['author'] )
			);

		}

	}

} );

add_action( 'rest_authentication_errors', function( $access ) {

	if(
		preg_match( '/users/', $_SERVER['REQUEST_URI'] ) !== 0
		|| isset( $_REQUEST['rest_route'] ) && preg_match( '/users/', $_REQUEST['rest_route'] ) !== 0
	) {

		if( ! is_user_logged_in() ) {

			return new WP_Error(
				'rest_cannot_access',
				esc_html__( 'Only authenticated users can access the User endpoint REST API.', 'stop-user-enumeration' ),
				array( 'status' => rest_authorization_required_code() )
			);

		}

	}

	return $access;

} );