Data protection policy that triggers MIME type has been applied to PDF or image files even though MIME type of attached files is not selected.
Listed MIME type: application/octet-stream
Not listed MIME type: application/pdf, image/png etc.
application/octet-stream is the default value for a binary file. The meaning of this MIME type is “unknown binary” file. It represents any kind of binary data.
Examples of the reasons that attachment files are detected:
Note: Even if the attachment file is detected as application/octet-stream, Data Protection detail report may not have a reference for the file detected. The report is designed to list attached files to the email, not a file that is found inside of the attachment.
To avoid unexpected trigger by application/octet-stream, instead of listing application/octet-stream in Attachment MIME Type List, using attachment Filename list condition with file extensions (e.g. *.exe, *.bin) and the MIME type list is recommended.
CONTAINS (2) Rule(s)
Attachment MIME Type List (excluding application/octet-stream)
Attachment MIME Type List (application/octet-stream only)
Attachment Filename List (executable file extensions)