[CentOS] Detecting empty office doc containing virus macro

[Ned Slider]

On 28/10/15 11:55, Gary Stainburn wrote:
> We are receiving LOTS of emails that contain empty XLS or DOC documents with 
> embedded virus macros.  These are getting past SPAMASSASSIN, Clamav and 
> Kaspersky.
> 
> I'm trying to write a filter for EXIM to block these emails but I need to know 
> a good, quick, command-line to detect an empty doc with a macro.
> 
> Is there anything available that I can use??
> 
> I have managed to write a PERL script to detect empty xls xlsx, doc and docx 
> files but I cannot detect whether they have any macros embedded
> 
> Gary

If you've got a script to detect empty docs then it should be relatively
easy to detect these. I assume empty attachments are not normal in your
mail flows?

I would look to write some custom SpamAssassin rules, maybe
incorporating your script, to detect these and filter them out.

Are you able to post some examples to pastebin?