Badmail from postmaster

My exchange server seems to be allowing the postmaster@mydomain.com to send & receive mail with virus attachments.  My virus scanning software stops it before it sends it out or receives it.  It seems like different username is sending it out with the name of postmaster being used instead.

These files are being sent to the badmail folder & causing it to be filled up.  I have tried many troubleshooting options but none of them seem to have worked.  The badmail problem has just became a problem a week ago.  I have slowed them down to a handfull a day compared to thousands in a day.

I have not tried this yet, can the postmaster be removed as an email address?

It is hard to explain what is happening.  So, it you have any questions just ask.

Thanks.
klh-asiAsked:
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OneHumpConnect With a Mentor Commented:
You really don't want to mess with postmaster.  To be RFC compliant, you really need a working postmaster address.  What you are seeing is a virus out there spoofing your postmaster address when sending to your addresses or others on the Internet.  It's a chronic and currently uncorrectable problem that everyone is dealing with right now.

My best suggestion is to create a rule that keys in certain garbage words to get rid of NDRs and warnings and write a batch file to clear out your badmail folder and schedule it to run every week or so.

OneHump
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klh-asiAuthor Commented:
How can the postmaster send it to a_made_up_name@mydomain.com?  Thanks for the comment.  
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OneHumpCommented:
Probably a dictionary harvest attack.  It's hard to say on a message board like this without being there.  :)

Dictionary harvest attacks involve a spammer traversing through your directory by sending to fake names and discarding "user unknowns".  They can use any sender they want, including postmaster.  There are solutions for DHAs, but they are expensive.  They act as sort of an Email IDS.  Ironport, Trend, CipherTrust and others all have solutions that can key in on multiple rcpt to's and drop connections when certain conditions are met, like x number of "user unknowns" in a given time fram.

The strangeness that comes into the average postmaster mailbox is mind boggling at best.

OneHump
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