All the emails have headings like this: your account is about to be closed, your new password has been updated, your new password has been accepted, your account may be in violation. When I open an email there are just "attachments" which I am not opening.
It appears what is happening is very commonly called a "dictionary attack" and in this case it appears the SPAM message has an attached virus. A dictionary attack is a single SMTP connection that attempts to send email from a spam source to a random set of names on a domain, e.g. [email protected][email protected][email protected], in the hope that one of the hundreds will get a hit and deliver in your case the virus.
If you are using cPanel I suggest you use :fail: rather then blackhole for disabling the catch-all as it is less resource intensive on the server. Additionally, you can setup forwards to go to your main address for other boxes such as sales or admin so you don't need a full e-mail box for them, but they will not be rejected by the server. Also if you have the ability to, you may want to enable SpamAssassin on your server to filter out blatent SPAM messages, you can then create a "filter" to automatically delete the message with the SpamAssassin header, so you don't have to check them and they are automatically discarded.