[Mimedefang] Operating on attachments - choosing which attachment to operate on

[David F. Skoll]

On Thu, 24 Apr 2014 17:27:18 +0000
Michael Lazar <Michael.Lazar at pkware.com> wrote:

> 1) An email with an encrypted ZIP file is received
> 2) Copy the attachment and use action_external_filter to decrypt the
> attachment and re-compress it
> 3) Rename the new attachment to a static name (i.e. clear.zip)
> 3) Add the newly decrypted zip file to the original email (now the
> email has two zip files - the original encrypted and the unencrypted
> version) 4) Allow the email to continue to the DLP infrastructure
> where the unencrypted zip will be scanned normally and if allowed
> will be stripped off
> 5) The message continues as normal

That most likely won't work too well.  I think you need to do it from
filter_end and traverse the MIME entity $entity in there, adding parts
as needed.

Regards,

David.