This script sanitize @@@nopass@@@ passwords generated by OneLogin SAML plugin <= 2.1.8

fixpw.php

<?php
/**
 * This script search user with @@@nopass@@@ passwords and replace them by random passwords
 */

/** Sets up the WordPress Environment. */
require( dirname(__FILE__) . '/wp-load.php' );

$users = get_users();

foreach ($users as $user) {
    $user = wp_authenticate($user->user_login, '@@@nopass@@@');
    if (!is_wp_error($user) ) {
        $user->user_pass = wp_generate_password(20, true);
        wp_update_user($user);
    }
}

We've created an enhanced version of this script that fits our use case better https://gist.github.com/TheLastCicada/97d3fd6d66f0301691b8bce315aeeb60 and provides feedback about what is happening when the script is running. You are welcome to integrate any changes into your script here if desired.