When exporting Endpoint SMTP incidents to CSV file, the Attachment name from the E-mail Message does not appear.
Component : Enforce Reporting
This is a known limitation of the products default CSV export.
Use the REST 2.0 API documentation for your relevant version - for example, 15.7: https://apidocs.symantec.com/home/DLP15.7 to query this value.
There is an enhancement request, ISFR-559