unwanted virus infected email spam

(kind of off topic) Has anyone been receiving periodic emails with virus infected attachments from an address proporting to be hahaha@sexyfun.net? It is really annoying me at this point because this w**ker seems to be sequentially trying all combinations ********@storm.ie and I am getting a couple of quarantine notifications every week from the antivirus software on our mail server. I did try adding a REJECT rule for hahaha@sexyfun.net to /etc/mail/access - this seemed to work for a week or two but the problem has since returned. Any ideas as to what I might try next as this kind of mindless activity really does my head in ... Thanks, Michael