W3C home > Mailing lists > Public > public-webappsec@w3.org > December 2014

Re: [blink-dev] Re: Proposal: Marking HTTP As Non-Secure

From: Jeffrey Walton <noloader@gmail.com>
Date: Fri, 26 Dec 2014 21:43:50 -0500
Message-ID: <CAH8yC8nqA9R8+tzHtnawpaDEAksZJJ=RzH=HOh=uKxXXOvpaPw@mail.gmail.com>
To: Austin William Wright <aaa@bzfx.net>
Cc: "dev-security@lists.mozilla.org" <dev-security@lists.mozilla.org>, security-dev <security-dev@chromium.org>, "public-webappsec@w3.org" <public-webappsec@w3.org>, blink-dev <blink-dev@chromium.org>
> If we want to talk about the perspective of servers, the server has options
> to demand a secure connection too; it simply has to deny plaintext requests
> ...

Actually, no. Middleware boxes and a class of active attackers can do
whatever they want.

The control to stop most of the intercept related attacks - public key
pinning - was watered down by the committee members to the point that
the attacker effectively controls the pinset. (Here, I'm making no
differentiation between the "good" bad guys and the "bad" bad guys
because its nearly impossible to differentiate between them).

That is, the standard could have provided policy and the site could
have sent a policy that governed the pinset. The site could have
allowed an override or denied an override. But it was decided all
users must be subjected to the interception, so the policy elements
were not provided.

So how's that for strategy: the user does not get a choice in their
secure connection and the site does not get a choice in its secure
connection. Rather, some unrelated externality makes the choice.

Jeff

On Fri, Dec 26, 2014 at 8:33 PM, Austin William Wright <aaa@bzfx.net> wrote:
>
> On Wed, Dec 24, 2014 at 3:43 PM, Alex Russell <slightlyoff@google.com>
> wrote:
>> ...
>>
>> No, the request for a resource means something. Security is about the
>> quality of service in delivering said thing.
>
> Specifically, I refer to privacy and authentication (which seems to be what
> "security" means here). There's many components to security, and they're not
> all going to be desired at the same level for every request, sometimes even
> at odds with each other. Deniability is a particularly expensive one to
> implement, often at significant monetary and performance cost to the user.
> Deniability is simply not implemented by any website (or more accurately,
> any authority) indexed by the major search engines.
>
> It's difficult to claim that deniability, though, is about "quality of
> service", but it is nonetheless considered something _very_ important by
> Tor, and by users of it.
>
>>
>> > HTTP could mean, simply, "I don't care about security".
>>
>> Then user agents should be free to act on behalf of users to write off
>> correspondents who do not value the user enough to protect the message in
>> transit.
>>
>> You're making claims about what UA's must do from the perspective of
>> servers; this is a clear agency problem misunderstanding.
>>
>> We're the user's agent, not the publisher's.
>
> When a user navigates to an https:// resource, or hits the checkbox for
> STARTTLS, or selects "Require encryption" from a drop-down, they, the user,
> are *demanding* a secure connection (for someone's definition of secure;
> traditionally this means privacy and authentication but need not include
> deniability).
>
> If we want to talk about the perspective of servers, the server has options
> to demand a secure connection too; it simply has to deny plaintext requests
> (it could redirect, but this risks the user-agent sending sensitive
> information including request-uri that'll just be ignored), and TLS can
> specifically ask for or require a client TLS certificate for authentication.
>
> The user-agent works for the user, not the other way around. Letting a
> user-agent intervene in the case of a plaintext request is imposing a value
> on the user: It prioritizes privacy over "DO NOT BREAK USERSPACE!" which is
> not *necessarily* true.
>
> If TLS were free or very cheap to implement, however, this would be a
> non-issue. Hence my treatment of ways to do this.
>
> Even if the http-as-non-secure proposal fully worked; it still increases the
> cost of publishing content and barriers to entry. I recall Tim Berners-Lee
> recollecting that requiring users mint a long-lived URI was concerning cost;
> but there was no other way to design a decentralized Web. (In the end, the
> biggest barrier to entry has been acquisition of a domain name and hosting.)
>
> Of course, if efficiency and security are at odds, then we prefer security.
> However, I see making TLS implementation cheaper as a viable alternative to
> this proposal, and so is far more appealing.
>>
>> > A TLS failure means "Security is _required_ by the other party, but
>> > couldn't be set up and verified. Abort! Abort!"
>> >
>> > Purporting that plaintext and HTTPS failure is the same would be
>> > conditioning users to be less worried about HTTPS failures, where there's a
>> > known _requirement_ for confidentiality.
>>
>> The UA could develop different (but also scary) UI for these conditions.
>
> I am specifically referring to the part of the proposal that, in the long
> term, specifies no UI difference between plaintext and failed-TLS.
>
> Would you care to make an alternate proposal with this change?
>>
>> Regardless, we have done a poor job communicating the effective system
>> model (that content is not tamper-evidentwhen served over HTTP). Steps to
>> make this clearer aren't the same thing as throwing all distinction
>> overboard.
>>
>> > There may be some value in saying "as with many network requests,
>> > request/submission is being sent in the clear. Anyone on your network will
>> > be able to read this!". But big scary warnings are most certainly bad. No
>> > matter what, before I claim anything for sure, I would like to see a
>> > double-blind study, and not change for the sake of change.
>>
>> This sort of argument might have worked in '12. Apologies, but you're
>> dreadfully late.
>
> I'm afraid snark wasn't my first language, so you'll have to refresh my
> memory: what are you referring to?
>
> Earlier in my message, I touched on the danger of users dismissing warnings
> for their e.g. bank, because users become dismissive of "insecure
> connection" warnings found elsewhere.
>
> Now, we might have HSTS (for my bank example), but at that point we're no
> longer talking about two tiers of security, but three (insecure-bypassable,
> insecure-nonbypassable, secure), which is precisely what the proposal is
> advocating moving _away_ from (or, the proposal is not very clear on this
> point, and a clarification in its text would be necessary).
>> ...
Received on Saturday, 27 December 2014 02:44:17 UTC

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