Re: Alt-Svc Privacy Concerns

Matthew Kerwin <matthew@kerwin.net.au> Sun, 10 April 2016 04:52 UTC

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From: Matthew Kerwin <matthew@kerwin.net.au>
To: Phil Lello <phil@dunlop-lello.uk>
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Subject: Re: Alt-Svc Privacy Concerns
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On 10/04/2016 4:33 AM, "Phil Lello" <phil@dunlop-lello.uk> wrote:
>
> This is a slightly different issue than the described scenario, and I'm
far from certain that the risks are adequately highlighted there.
>
> "By using unique names, servers could conceivably track client requests."
seems incredibly weak to the point of being dismissive, since it suggests a
per-client hostname being generated, and that it's incredibly unlikely
anyone would bother.
>
> IMHO, it's quite likely that multiple seemingly unrelated sites operated
by the same entity might legitimately converge users to a common
servername. It's quite likely that at this point that the user agent would
see these as candidates for sharing the same connection. It seems
reasonable that there should at least be a recommendation for a user agent
to warn users that there is significant potential for being tracked, and
gain consent.
>

This sounds like a UX thing -- incognito sessions oughtn't reuse
connections for different URI hostnames, even if the alt-svcs point to the
same name. The consent, then, is not being incognito.

Is it worth documenting this risk/advice somewhere, or is it already
self-evident?