code: public static function hostCheck(string $host = null) : bool
      {
          if (!$host) {
              $host = (string)$_SERVER['HTTP_HOST'];
          }
  
          return getenv(static::DOMAIN_ENV_LABEL) !== false
              && strrpos(strrev($host), strrev('.' . getenv(static::DOMAIN_ENV_LABEL))) === 0;
      }
docs: Проверка хоста, например, $_SERVER['HTTP_HOST'] на уязвимость.
  Подробнее на https://expressionengine.com/blog/http-host-and-server-name-security-issues
  
  @param string $host
  
  @return bool