Ways to filter other document types

[Alex Neuman van der Hans]

Any ideas on how to block word or pdf spam, as mentioned in:

http://searchsecurity.techtarget.com/columnItem/0,294698,sid14_gci1214687,00.html

It could be an interesting option to add to the phishing filter or to 
SA, as spammers are now using these formats. Something like the TNEF 
unpack-then-repack approach we're getting now, would probably be the way 
to go.

Anybody already doing something similar?