Quoting David Laight (david@l8s.co.uk):
> > Me?  I get several hundred viruses sent per month to me.  mutt
> > and MacOS 10's Mail.app just won't run them.  I don't care.  It's
> > like worrying about catching dutch elm disease.
> 
> Actually it is probably more likely that dutch elm disease will
> leap the species barrier than someone will write a virus for mutt.
> 
> Of course, if you are trully paranoid, you run your MUA (and
> browser) inside a chroot jail.

Well, no.  It would require that mutt (or tools it calls)
take the data its showing and execute it.  That's far from
the default.  Sure, buffer overflows are found (but strangely,
nobody attacks OpenBSD on a MIPS box, so I get core dumps if
anything).

lookOut not only runs attachments, but they define several
proprietary attachment types and it will read the most bizarrely
broken MIME attachments out there.  And 6 versions of outlook
all behave differently.  Joy for folks who write email virus
scanners.

A cement wall will never get a tree disease.