lubuntu.me/plugins/all-in-one-wp-security-and-firewall/other-includes/wp-security-stop-users-enumeration.php

<?php

/*
 * Merged by Davide Giunchi, from plugin "Stop User Enumeration" url "http://locally.uk/wordpress-plugins/stop-user-enumeration/" by "Locally Digital Ltd"
 */

if (!is_admin() && isset($_SERVER['REQUEST_URI'])) {
    if (preg_match('/(wp-comments-post)/', $_SERVER['REQUEST_URI']) === 0 && !empty($_REQUEST['author'])) {
        wp_die('Accessing author info via link is forbidden');
    }
}