On Fri Apr 15 18:38:50 2011, Keith Moore wrote:
Bouncing is absolutely what should happen if the message is merely
malformed. Otherwise, the sender has no idea that his message
didn't arrive (or why), and nothing will ever be done to fix the
problem.
But the problem is that the message didn't arrive. The reason is that
it's malformed, but that's not the problem that people care most
about. Now, *we* may care, but that's a wholly different thing, and
largely irrelevant to the average user.
Bouncing has problems too - it's trivial to use such a server to
bounce malformed MIME back to some other address which then processes
the MIME and allows some malware through.
As I said before, differences in error handling behaviour may result
in malware vectors being available. If you standardize the error
handling (to whatever you like - pass through, bounce, or reject)
then the net result is that exploits of this form cannot happen.
Dave.
--
Dave Cridland - mailto:dave(_at_)cridland(_dot_)net -
xmpp:dwd(_at_)dave(_dot_)cridland(_dot_)net
- acap://acap.dave.cridland.net/byowner/user/dwd/bookmarks/
- http://dave.cridland.net/
Infotrope Polymer - ACAP, IMAP, ESMTP, and Lemonade