We know how to reject executables and other potentially dangerous file extensions via mime_header_checks directive:
mime_header_checks = regexp:/etc/postfix/mime_header_checks (main.cf)
/name=[^>]*\.(bat|com|exe|dll|vbs)/ REJECT (mime_header_checks)
This way bat,com,exe,dll,vbs are gone. But, since there's OS's that treats extensionless files like executables, it came to my mind that these should be blocked also.
How to have that/what would be regexp to match these files along with known executables?
How about adding
It will match if there is dot anywhere else than for separating the (max. 4 character) extension
but won´t match
Just add to number "{7}" if you wish to allow longer extensions.