I heard a story of the vulnerability being exploited on several sites, a new backdoor created, and then the hax0r applied the drupal update to close the door be

I heard a story of the vulnerability being exploited on several sites, a new backdoor created, and then the hax0r applied the drupal update to close the door behind them. So, don't just check if the site was updated, check if the site maintainer applied the update.