Re: [OAUTH-WG] problem statement

[Eran Hammer-Lahav <[e-mail]>]

You are one making the argument that no one should be installing apps.

There is no known way to stop users from installing malware and viruses other than not letting them install anything off a whitelist. The problem you are describing has nothing to do with OAuth, its a fundamental problem with running untrusted code on your devices. Once you do that, yes, OAuth can be exploited but that's true for every authentication scheme when one side is compromised.

My point, which you seems to miss, is that the same argument can be made against any other protocol. TLS offers your certain protections but they are all gone if you install a bad native app – following your logic people should not use TLS in apps either.

I do not consider this an issue.

EHL

From: Michael Thomas <[e-mail]<mailto:[e-mail]>>
Date: Tue, 6 Sep 2011 11:58:11 -0700
To: Eran Hammer-lahav <[e-mail]<mailto:[e-mail]>>
Cc: "[e-mail]<mailto:[e-mail]>" <[e-mail]<mailto:[e-mail]>>, "[e-mail]<mailto:[e-mail]>" <[e-mail]<mailto:[e-mail]>>
Subject: Re: [OAUTH-WG] problem statement

Eran Hammer-Lahav wrote:
I'm dismissive of this being an OAuth problem.

Which brings us back to my original problem: what is the problem it's trying to solve?
What are the assumptions it makes? What is its applicability? None of those are addressed
very well if at all in the drafts. I'm sure that I'm not the only one who would be very
surprised to hear that using oauth on a phone app is a bad idea.

Put it this way: your favorite example of a photo printing service needing access to flickr.
It's ok if you do that from a browser, but not if the photo printer makes an app. How many users,
exactly, are going to know that they shouldn't do the second one?

I think that's an oauth problem because oauth makes it *seem* like you're protected from
the third party, whereas if the app itself asked for your login credentials there would
be far less confusion. So in that sense, oauth is making things worse, not better.

Mike

EHL
On Sep 6, 2011, at 11:35, "Michael Thomas" <[e-mail]<mailto:[e-mail]>> wrote:
Eran Hammer-Lahav wrote:
Don't install crap on you device or computer. OAuth is the least of your concern if you install bad software.

If there was a solution to this we would not need an antivirus.
How exactly does an end user know what is "crap" or not? Or are you just dismissive of apps in
general? I don't think that apple and google are going to close up shop because it breaks oauth's
trust model.

Mike

EHL

On Sep 6, 2011, at 11:23, "Michael Thomas" <[e-mail]<mailto:[e-mail]>> wrote:

Eran Hammer-Lahav wrote:
I agree. If you are going to install a native app, you better trust it not to do bad things. Grabbing your password is the least interesting thing such an app can abuse. I don't see any need to change the v2 draft.
How, exactly, is the user supposed to protect themselves against rogue apps?
It sounds like the solution is to tell them to never use oauth in an app at all.

Is oauth only intended to be used on standalone trustable web browsers? I don't recall
seeing that anywhere.

Mike

EHL

On Sep 6, 2011, at 11:10, "Igor Faynberg" <[e-mail]<mailto:[e-mail]>> wrote:

Mike,

You've got the problem statement right: allowing the user to authorize
resource access to another party without divulging user's credentials is
the objective of OAuth. You are also right in that the attack you have
described defies the whole purpose of OAuth.  I do not think though that
it is related to OAuth per se.

To this end, the security work led by Torsten has thoroughly analyzed
the protocol and specified protection against multiple protocol
attacks.  From what you described, it appears to me that the attack you
mention is not related to the protocol but rather to the user's
environment.  There is no possible protection from key loggers that a
protocol can implement. I could be mistaken; in any case, it looks like
the problem rests with the implementation of WebView.

If I am wrong, I would appreciate a detailed description of what happened.

Igor

On 9/6/2011 1:40 PM, Michael Thomas wrote:
Hi all,

Barry suggested that I might subscribe and explain what I sent him.

My basic problem is that in neither the protocol nor the threats drafts,
I can't seem to find what problem is actually trying to be solved with
oauth, and what assumptions you're making about various elements.

Here's what I did. I've written an app, and I wanted re-integrate the
ability to send tweets after they deprecated Basic. So the app has a
webView (android, iphone...) which it obviously completely controls.
With oauth, the webview UA will ultimately redirect off to Twitter's
site to collect the user's credentials and grant my app's backend an
access token (sorry if I get terminology screwed up, i'm just coming
up to speed).

What occurs to me is that webview affords exactly zero protection from
my client (ie, the app) from getting the user's twitter credentials. All
I have to do is set up a keypress handler on that webview and in a few
minutes of hacking I have a key logger. etc.

So what I can't tell is whether this is a "problem" or not, because I
don't know what problem you're trying to solve. If the object of oauth
isn't to keep user/server credentials out of the hands of a third party,
then what is it trying to solve? Is there an expectation that the
UA is trusted by the user/server? What happens when that's not the case?

Regardless of whether I'm misunderstanding, it would sure be nice to have
both the problem and your assumptions laid out, hopefully with some
prominence
so you don't get these sort of dumb questions.

Mike
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