Possible problem with Gnus

[Richard Stallman]

We have to pay attention to an issue of how Gnus and other Emacs mail
readers treat MIME attachments.

Windows viruses often spread in attachments for Word.  We have to make
sure that attachments don't become a method for spreading viruses in
Emacs.  Some kinds of attachments run applications that perhaps can be
assumed safe, such as a gif displayer.  But attachments that run more
complex attachments, such as a browser that might execute programs
given it, have to be treated as unsafe.

I don't use Gnus.  How does a Gnus user specify to display an
attachment?  Does the user do this for one specific attachment,
or for all the attachments in one message?  Does Gnus ever display
attachments in a message without a specific direct user request
for that message?