Re: [OAUTH-WG] problem statement

Michael Thomas <mike@mtcc.com> Tue, 06 September 2011 18:48 UTC

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Date: Tue, 06 Sep 2011 11:50:13 -0700
From: Michael Thomas <mike@mtcc.com>
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Cc: "oauth@ietf.org" <oauth@ietf.org>
Subject: Re: [OAUTH-WG] problem statement
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William Mills wrote:
> OAuth doesn't solve this problem, and can't.  Generally the question is 
> whether the app appears to come from a reputable source, and nowadays 
> whether it's signed (in windows land) or otherwize certified by the 
> provider.
> 
> If you manage to solve this problem in a real way I'd be interested in 
> investing in your company.

Then what I don't see anywhere is that oauth is not applicable to embedded
web objects, and that end users should *never* trust oauth in a, say, phone
app. As far as I can tell, the server deploying oauth can't tell that it's
being misused, so this is all on the shoulders of the end user.

It sure looks like oauth is easily subverted in the real world.

Mike

> 
> ------------------------------------------------------------------------
> *From:* Michael Thomas <mike@mtcc.com>
> *To:* Eran Hammer-Lahav <eran@hueniverse.com>
> *Cc:* "oauth@ietf.org" <oauth@ietf.org>
> *Sent:* Tuesday, September 6, 2011 11:34 AM
> *Subject:* Re: [OAUTH-WG] problem statement
> 
> 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" <mike@mtcc.com 
> <mailto:mike@mtcc.com>> 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" 
> <igor.faynberg@alcatel-lucent.com 
> <mailto:igor.faynberg@alcatel-lucent.com>> 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
>  >>>>> _______________________________________________
>  >>>>> OAuth mailing list
>  >>>>> OAuth@ietf.org <mailto:OAuth@ietf.org>
>  >>>>> https://www.ietf.org/mailman/listinfo/oauth
>  >>>> _______________________________________________
>  >>>> OAuth mailing list
>  >>>> OAuth@ietf.org <mailto:OAuth@ietf.org>
>  >>>> https://www.ietf.org/mailman/listinfo/oauth
>  >>> _______________________________________________
>  >>> OAuth mailing list
>  >>> OAuth@ietf.org <mailto:OAuth@ietf.org>
>  >>> https://www.ietf.org/mailman/listinfo/oauth
> 
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