We have a new client that has a Drupal website that is e-commerce and sells women's fashion. A couple of days ago the site was compromised in some way and the previous company (who built the site) is no longer available to assist in addressing the issue of security within the site. We believe it was hacked in some way (can't tell if it was a virus or a human hacker). So we need to work out what happened as things like the email notifications for the orders have been inconsistently being emailed into my clients inbox.
We also need to confirm items like whether the credit card details of the customers have been obtained by hackers and hence figure out which areas need better security and implement a solution here.
Please let me know if available as I need help asap. Thanks.