HTTP POST requests are also a lot more difficult to cache server side compared to URI's which are easier to cache. I'm likely not explaining this well, but I believe it's a webscale concern.
-- Jim Manico @Manicode > On Jul 1, 2016, at 11:01 PM, Oleg Gryb <oleg_g...@yahoo.com> wrote: > > AFAIR, they were talking about cost of this additional POST on the server > side, which was not good for high volume traffic (millions requests per day). > I'll try to dig it out to find more details. > > > From: Liyu Yi <liy...@gmail.com> > To: John Bradley <ve7...@ve7jtb.com> > Cc: Oleg Gryb <o...@gryb.info>; Jim Manico <j...@manicode.com>; > "oauth@ietf.org" <oauth@ietf.org> > Sent: Friday, July 1, 2016 1:42 PM > Subject: Re: [OAUTH-WG] Security concern for URI fragment as Implicit grant > > 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 Security >>> https://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, >>>> 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 list >>>> OAuth@ietf.org >>>> https://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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