[Exim] filtering on email attachments

I realise that this is somewhat 'off topic' for this list but please help
as I'm running out of ideas fast!

I have been working on a method to quarantine emails that contain certain
attachments (word and excel documents specifically) and have been able to do
so using the 'generic attachment system filter' that I found in the list
archives. Whilst I accept that this is not really the job of an MTA, I have
not been able to find an alternative application that does what we need (ie:
letting the end user accept the responsibility for the document rather than
an admin user).

Unfortunately the powers that be only want documents that contain macros
to be quarantined rather than every document and I have no idea how to do
this! I realise that the attachments will need to be decoded and then passed
to <some program> to check for the presence of macros, so far I have been
unable to locate such a program.... If it can be done within Perl then that
will be fine as I can then do the entire filter in perl.

Can anyone help or point me in the right direction?

Thanks in advance,
Ian