“SPE should quarantine an attachment if the file is in a different file format than its extension indicates”
When we tested Symantec Protection Engine, we noticed that if a file extension on an attachment does not match the attachment file type (eg test.exe has been renamed as test.doc) then SPE does not report a violation or quarantine the file.
Whereas "Symantec Mail Security for Domino" did perform this file type to extension validation
Symantec support advised that Symantec Protection Engine would still scan the file for viruses but would not quarantine on a file type mismatch.
In a Vulnerability Test performed on our web application in October 2016 the VA testers raised this as an issue and requested that we raise a Request for development for SPE with Symantec.
Request you to support and help enable this feature within Symantec Protection Engine future release.