On Tue, Dec 6, 2011 at 8:45 PM, Stephen J. Turnbull <stephen@xemacs.org> wrote:
What do these DKIM-strict domains do with digests? Do they actually check the content (ie, individual messages) for source domain and verify their DKIM signatures?
Typically the digest appears to come from the list, so that's ok. There's no way to verify the contents with DKIM anyway at that point, anyway.
If not, just have those people who aren't getting messages turn on digest mode with maximum frequency. :-)
:) I'm not too worried about digests. They tend to look pretty different from the average phish, even when they only contain one message.
Of course, all the phishers out there are reading this message, and will shortly be using this technique to phish gmail users, so you'll have to extend DKIM checks to the content of digests and forwards....
What really ought to be done is to format secured messages as multipart, and sign the overall header "From" and individual parts (perhaps identified by some kind of content ID). Then have the *MUA* (not the MTA!) check for alleged sender, and for highly-phishable alleged senders display *only* authenticated portions (plus maybe buttons to see unauthenticated content at user option).
Yeah, unfortunately pushing this problem to the MUA introduces nearly as many problems as it solves. At the MTA we can't really know what the MUA is going to display (even in Gmail's case, because some people fetch their mail and view with another client) so the only safe thing to do is to make sure that all of it verifies.
Thanks, Monica