Back in January, Microsoft has annouced that the Exchange Online Transport Rule (ETR) Condition “Attachment ist Password protected” will now also support PDF Files.
You can read the Documentation:
If you look at a PDF (File > Properties)
Security > Show details
Note: Files with “Permissions Password” (Print, Edit and Copy Blocks with Password) are not affected by the Condition “Attachment ist Password protected”
There is also a “Open File Password”. In that case you’re prompted to open to enter the Password when you open the PDF File.
Note: Only these Files are affected by the Condition “Attachment ist Password protected”
You can see this on the PDF Property
I have such a Exchange Transport Rule
with the Condition “is password protected”
If you need PDF’s excluded from the Exchange transport Rule you can create an Exception
Except if: Any Attachment File extension includes the following extension: pdf
Aldough i do not recommend this solution - there might be some cases where this might be a fit
How to Create a PDF with “Document Open Password”
Select “Encrypt the document with a password
Enter a Password to Open the Document