[Cryptography] phishing, was Encryption opinion

Tom Mitchell mitch at niftyegg.com
Tue Sep 9 21:09:25 EDT 2014


On Tue, Sep 9, 2014 at 10:49 AM, John Levine <johnl at iecc.com> wrote:

> >> This battle was lost long, long ago.  ISPs routinely intercept
> >> NXDOMAIN DNS results and replace them with A records pointing to a web
> >> server with "helpful" paid ads.
> >I've always found this one complicated.  If done without the end user's
> permission, it's an issue.  But there are
> >people who believe it's bad even *with* the end-user's permission - for
> reasons I find hard to follow.
>
> There's a good reason and a bad reason.
>
> The bad reason is that it violates the holy end-to-end principle, of
> which the less said the better.
>
> The good reason is that not all DNS lookups are for web pages.  Pick a
> service
> <cryptography at metzdowd.com>
>

The bit about "end user's permission" is fragile.  It is hard enough to
structure a contract or agreement between two.   If all the players in the
middle and on the periphery could modify anything they see establishing
bounds for a permission map seems impossible.

Traceroute to mail1.metzdowd.com returns 17 route points.   Any of these
could
do packet inspection and modify content.  That is simple mail... other
protocols may
have other interactions.  Mind you not mail headers just  network
routing....

The warm red flannel shirt you order for the winter could become a used
t-shirt in transit with some awkward printing on it to boot as the package
moves through hands in transit.

We hear of luggage theft in airports as it moves from intake, to
inspection, to building
to staging, to aircraft to.....  Theft is one thing, evil or malicious
injection of stuff is also
within the bounds of possibility and in this paranoid world the risks grow
and I will not
speculate on the possible abuses.

This is in contrast to address specific content...   Say Xfinity buys a
space on a
web page that has a link to Xfinity content.php that looks at the
destination
and  JavaScript decides what you see in that space.  It gets interesting if
the
local router passes data via a side channel to the server so the .php server
side has more state than is obvious.     A WiFi box could place you are in
a
locker room, powder room, gun range, poolside, nature beach.....   What
we cannot see is the back channel data flow.  Authentication ensures that
some
data flow must take place.

The end to end no molestation contract and legislative framework to
eliminate back channels
both seem important to me.







-- 
  T o m    M i t c h e l l
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