Yes but POST doesn't really work for in browser apps.

If it is a server app it should be using the code flow with GET or POST as
you like.

If we do a  post message based binding it will be targeted at in browser
applications.

John B.

On Fri, Jul 1, 2016 at 4:42 PM, Liyu Yi <liy...@gmail.com> wrote:

> BTW, I do not see any significant performance concerns for post. Parsing
> and executing the Javascript logic for post operation will be on the client
> side, no extra server load is introduced.
>
> Plus post will remove the size restriction of the URL length.
>
> -- Liyu
>
> On Fri, Jul 1, 2016 at 1:35 PM, Liyu Yi <liy...@gmail.com> wrote:
>
>> Thanks for the great comments and advices.
>>
>> I think it is a good idea for the working group to revise the fragment
>> part in the spec, since there might be public available tools already
>> implemented this approach and people can end up with a solution with
>> serious security loopholes.
>>
>> The re-append issue can be mitigate by a logic on Resource Server which
>> carefully re-writes/removes the fragment in any redirect, if the the
>> redirect can not be avoided.
>>
>> -- Liyu
>>
>>
>> On Fri, Jul 1, 2016 at 11:33 AM, John Bradley <ve7...@ve7jtb.com> wrote:
>>
>>> This behaviour started changing around 2011
>>>
>>> From HTTP/1.1
>>> See https://tools.ietf.org/html/rfc7231#section-7.1.2I
>>>       f the Location value provided in a 3xx (Redirection) response does
>>>
>>>    not have a fragment component, a user agent MUST process the
>>>    redirection as if the value inherits the fragment component of the
>>>    URI reference used to generate the request target (i.e., the
>>>    redirection inherits the original reference's fragment, if any).
>>>
>>>    For example, a GET request generated for the URI reference
>>>    "http://www.example.org/~tim"; might result in a 303 (See Other)
>>>    response containing the header field:
>>>
>>>      Location: /People.html#tim
>>>
>>>    which suggests that the user agent redirect to
>>>    "http://www.example.org/People.html#tim”
>>>
>>>
>>>    Likewise, a GET request generated for the URI reference
>>>    "http://www.example.org/index.html#larry"; might result in a 301
>>>    (Moved Permanently) response containing the header field:
>>>
>>>      Location: http://www.example.net/index.html
>>>
>>>    which suggests that the user agent redirect to
>>>    "http://www.example.net/index.html#larry";, preserving the original
>>>    fragment identifier.
>>>
>>>
>>>
>>> This blog also explores the change.
>>>
>>> https://blogs.msdn.microsoft.com/ieinternals/2011/05/16/url-fragments-and-redirects/
>>>
>>>
>>> On Jul 1, 2016, at 1:05 PM, Oleg Gryb <oleg_g...@yahoo.com> wrote:
>>>
>>> "Browsers now re-append  fragments across 302 redirects unless they are
>>> explicitly cleared this makes fragment encoding less safe than it was  when
>>> originally specified" - thanks Jim. Looks like a good reason for vetting
>>> this flow out.
>>>
>>> John,
>>> Please provide more details/links about re-appending fragments.
>>>
>>> Thanks,
>>> Oleg.
>>>
>>>
>>> ------------------------------
>>> *From:* Jim Manico <j...@manicode.com>
>>> *To:* Oleg Gryb <o...@gryb.info>
>>> *Cc:* "oauth@ietf.org" <oauth@ietf.org>; Liyu Yi <liy...@gmail.com>
>>> *Sent:* Thursday, June 30, 2016 10:25 PM
>>> *Subject:* Re: [OAUTH-WG] Security concern for URI fragment as Implicit
>>> grant
>>>
>>> Oleg! Hello! Great to see you pop up here with a similar concern.
>>>
>>> John Bradley just answered this thread with the details I was looking
>>> for (thanks John, hat tip your way).
>>>
>>> He also mentioned details about fragment leakage:
>>>
>>> "Browsers now re-append  fragments across 302 redirects unless they are
>>> explicitly cleared this makes fragment encoding less safe than it was when
>>> originally specified"
>>>
>>> Again, I'm new here but I'm grateful for this conversation.
>>>
>>> Aloha,
>>> --
>>> Jim Manico
>>> @Manicode
>>>
>>> On Jul 1, 2016, at 1:24 AM, Oleg Gryb <oleg_g...@yahoo.com> wrote:
>>>
>>> We've discussed access tokens in URI back in 2010 (
>>> https://www.ietf.org/mail-archive/web/oauth/current/msg04043.html).
>>> There were two major objectives when I was saying that it's not secure:
>>>
>>> 1. Fragment is not sent to a server by a browser. When I've asked if
>>> this is true for every browser in the world, nobody was able to answer.
>>> 2. Replacing with POST would mean a significant performance impact in
>>> some high volume implementations (I think it was Goole folks who were
>>> saying this, but I don't remember now).
>>>
>>> AFAIR, nobody was arguing about browsing history, so it's valid.
>>>
>>> So, 6 years later we're at square one with this and I hope that this
>>> time the community will be more successful with getting rid of secrets in
>>> URL.
>>>
>>> BTW, Jim, if you can come up with other scenarios when fragments can
>>> leak, please share. It'll probably help the community with solving this
>>> problem faster than in 6 years.
>>>
>>> Thanks,
>>> Oleg.
>>>
>>>
>>> ------------------------------
>>> *From:* Jim Manico <j...@manicode.com>
>>> *To:* Liyu Yi <liy...@gmail.com>; oauth@ietf.org
>>> *Sent:* Wednesday, June 29, 2016 7:30 AM
>>> *Subject:* Re: [OAUTH-WG] Security concern for URI fragment as Implicit
>>> grant
>>>
>>> > Shouldn’t it be more secure if we change to use a post method for
>>> access token, similar to the SAML does?
>>> I say yes. But please note I'm very new at this and someone with more
>>> experience will have more to say or correct my comments.
>>> Here are a few more details to consider.
>>> 1) OAuth is a framework and not a standard, per se. Different
>>> authorization servers will have different implementations that are not
>>> necessarily compatible with other service providers. So there is no
>>> standard to break, per se.
>>> 2) Sensitive data in a URI is a bad idea. They leak all over the place
>>> even over HTTPS. Even in fragments.
>>> 3) Break the "rules" and find a way to submit sensitive data like access
>>> tokens, session information or any other (even short term) sensitive data
>>> in a secure fashion. This includes POST, JSON data payloads over PUT/PATCH
>>> and other verbs - all over well configured HTTPS.
>>> 4) If you really must submit sensitive data over GET , consider
>>> JWT/JWS/JWE (with limited scopes/lifetimes) to provide message level
>>> confidentiality and integrity.
>>> Aloha,
>>>
>>> Jim Manico
>>> Manicode Securityhttps://www.manicode.com
>>>
>>>
>>> On 6/27/16 9:30 PM, Liyu Yi wrote:
>>>
>>> While we are working on a project with OAuth2 implementation, one
>>> question arises from our engineers.
>>> We noticed at
>>> <https://tools.ietf.org/html/draft-ietf-oauth-v2-31#page-30>
>>> https://tools.ietf.org/html/draft-ietf-oauth-v2-31#page-30, it is
>>> specified that
>>>
>>> (C)  Assuming the resource owner grants access, the authorization
>>>         server redirects the user-agent back to the client using the
>>>         redirection URI provided earlier.  The redirection URI includes
>>>         the access token in the URI fragment.
>>>
>>> For my understanding, the browser keeps the URI fragment in the history,
>>> and this introduces unexpected exposure of the access token. A user without
>>> authorization for the resource can get the access token as long as he has
>>> the access to the browser. This can happen in a shared computer in library,
>>> or for an IT staff who works on other employee’s computer.
>>>
>>> Shouldn’t it be more secure if we change to use a post method for access
>>> token, similar to the SAML does?
>>> I feel there might be something I missed here. Any advices will be
>>> appreciated.
>>>
>>>
>>> _______________________________________________
>>> OAuth mailing listOAuth@ietf.orghttps://www.ietf.org/mailman/listinfo/oauth
>>>
>>>
>>> --
>>>
>>>
>>> _______________________________________________
>>> OAuth mailing list
>>> OAuth@ietf.org
>>> https://www.ietf.org/mailman/listinfo/oauth
>>>
>>>
>>>
>>> _______________________________________________
>>> OAuth mailing list
>>> OAuth@ietf.org
>>> https://www.ietf.org/mailman/listinfo/oauth
>>>
>>>
>>>
>>>
>>
>
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