Hello,
The most efficient way to obtain this information would probably be through Message Tracking. For example, you can perform a message tracking search, and then search for any attachments that contain * (wildcard). This should pull up any emails that came in with an attachment, and you can then generate a report based off of those results.
Keep in mind as well, in order for attachment information to be logged, you would need to have some sort of filter setup to be looking at/within/ETC an attachment.
For instance, you could use this Message Filter to simply log any attachments that come in on an email (Filters --> NEW from CLI) :
filename_filter:
if (attachment-filename == '.'){
log-entry("Attachment filenames $filenames");
}
Thanks!
-Dennis M.