Based on Hans' response to Nat I understand why this doesn't solve all
the use cases. It does still seem like a good idea from a client
perspective that would address the dynamic client registration cases
where the Bad AS is returning mixed endpoints.
On 1/27/16 7:43 AM, George Fletcher wrote:
Following up on Nat's last paragraph... did the group in Darmstadt
discuss this option? Namely, to require that the authority section of
the AuthZ and Token endpoints be the same? Are there known
implementations already deployed where the authority sections are
different? It seems like a simple check that would address the
endpoint mix-up cases.
Thanks,
George
On 1/26/16 8:58 PM, Nat Sakimura wrote:
John,
Nov is not talking about the redirection endpoint. I just noticed
that 3.1.2.1 of RFC 6749 is just asking TLS by "SHOULD" and I think
it needs to be changed to "MUST" but that is not what he is talking
about.
Instead, he is talking about before starting the RFC 6749 flow.
In many cases, a non TLS protected sites have "Login with HIdP"
button linked to a URI that initiates the RFC 6749 flow. This portion
is not within RFC 6749 and this endpoint has no name or no
requirement to be TLS protected. Right, it is very stupid, but there
are many sites like that.
As a result, the attacker can insert itself as a proxy, say by
providing a free wifi hotspot, and either re-write the button or the
request so that the RP receives "Login with AIdP" instead of "Login
with HIdP".
I have add a note explaining this to
http://nat.sakimura.org/2016/01/15/idp-mix-up-attack-on-oauth-rfc6749/
I also have added a bit of risk analysis on it and considered other
risk control measures as well.
It does not seem to be worthwhile to introduce a new wire-protocol
element to deal with this particular attack. (I regard code
cut-and-paste attack a separate attack.) I am inclining to think that
just to TLS protect the pre-RFC6749 flow portion and add a check to
disallow the ASs that has different authority section for the Auhtz
EP and Token EP would be adequate.
Nat
2016年1月27日(水) 2:18 John Bradley <ve7...@ve7jtb.com>:
Nov,
Are you referring to Sec 3.1.2.1 of RFC 6749.
Stating that the the redirection endpoint SHOULD require TLS, and
that the AS should warn the user if the redirect URI is not over
TLS (Something I have never seen done in the real world)
Not using TLS is reasonable when the redirect URI is using a
custom scheme for native apps.
It might almost be reasonable for the token flow where the JS
page itself is not loaded over TLS so the callback to extract the
fragment would not be as well.
Note that the token itself is never passed over a non https
connection in tis case.
I would argue now that it is irresponsible to have a non TLS
protected site, but not everyone is going to go along with that.
Using a http scheme URI for the redirect is allowed but is really
stupid. We did have a large debate about this when profiling
OAuth for Connect.
We did tighten connect to say that if you are using the code flow
then a http scheme redirect URI is only allowed if the client is
confidential.
John B.
On Jan 26, 2016, at 1:14 AM, Phil Hunt (IDM)
<phil.h...@oracle.com> wrote:
Still don't see it. Though i think the diagram is wrong (the rp
should redirct to the ua and not call the authz direct), the IDP
should either return an error or redirect the RP to TLS.
I don't see this as proper oauth protocol since the RP is MITM
the UA rather than acting as a client.
Phil
On Jan 25, 2016, at 19:57, nov matake <mat...@gmail.com> wrote:
In this flow, AuthZ endpoint is forced to be TLS-protected.
http://nat.sakimura.org/wp-content/uploads/2016/01/oauth-idp-mixup.png
However, RP’s redirect response which causes following AuthZ
request is still not TLS-protected, and modified on the
attacker’s proxy.
Section 3.2 of this report also describes the same flow.
http://arxiv.org/pdf/1601.01229v2.pdf
On Jan 26, 2016, at 12:37, Phil Hunt (IDM)
<phil.h...@oracle.com> wrote:
Also the authz endpoint is required to force tls. So if the
client doesn't do it the authz should reject (eg by upgrading
to tls).
Phil
On Jan 25, 2016, at 19:29, Phil Hunt (IDM)
<phil.h...@oracle.com> wrote:
When the RP acting as the client issues a authorize redirect
to the UA it has to make it with TLS
Phil
On Jan 25, 2016, at 17:53, Nov Matake <mat...@gmail.com> wrote:
It doen't say anything about the first request which
initiate the login flow.
It is still a reasonable assumption that RP puts a "login
with FB" button on a non TLS-protected page.
nov
On Jan 26, 2016, at 10:45, Phil Hunt <phil.h...@oracle.com>
wrote:
I would find it hard to believe that is true.
From 6749 Sec 3.1
Since requests to the authorization endpoint result in user
authentication and the transmission of clear-text credentials (in the
HTTP response), the authorization server MUST require the use of TLS
as described inSection 1.6
<https://tools.ietf.org/html/rfc6749#section-1.6> when sending requests to the
authorization endpoint.
Sec 3.1.2.1
The redirection endpoint SHOULD require the use of TLS as described
inSection 1.6 <https://tools.ietf.org/html/rfc6749#section-1.6> when the requested
response type is "code" or "token",
or when the redirection request will result in the transmission of
sensitive credentials over an open network. This specification does
not mandate the use of TLS because at the time of this writing,
requiring clients to deploy TLS is a significant hurdle for many
client developers. If TLS is not available, the authorization server
SHOULD warn the resource owner about the insecure endpoint prior to
redirection (e.g., display a message during the authorization
request).
Lack of transport-layer security can have a severe impact on the
security of the client and the protected resources it is authorized
to access. The use of transport-layer security is particularly
critical when the authorization process is used as a form of
delegated end-user authentication by the client (e.g., third-party
sign-in service).
Section 10.5 talks about transmission of authorization
codes in connection with redirects.
Also see 6819, Sec 4.4.1.1 regarding eavesdropping or
leaking of authz codes.
Phil
@independentid
www.independentid.com
phil.h...@oracle.com
On Jan 25, 2016, at 4:52 PM, nov matake <mat...@gmail.com>
wrote:
The first assumption is coming from the original security
report at http://arxiv.org/abs/1601.01229.
RFC 6749 requires TLS between RS and AS, and also between
UA and AS, but not between UA and RS.
The blog post is based on my Japanese post, and it
describes multi-AS case.
Nat's another post describes the case which can affect
single-AS case too.
http://nat.sakimura.org/2016/01/22/code-phishing-attack-on-oauth-2-0-rfc6749/
nov
On Jan 26, 2016, at 08:22, Phil Hunt
<phil.h...@oracle.com> wrote:
Sorry, meant to reply-all.
Phil
@independentid
www.independentid.com
phil.h...@oracle.com
Begin forwarded message:
*From: *Phil Hunt <phil.h...@oracle.com
<mailto:phil.h...@oracle.com>>
*Subject: **Re: [OAUTH-WG] Call for Adoption: OAuth 2.0
Mix-Up Mitigation*
*Date: *January 25, 2016 at 3:20:19 PM PST
*To: *Nat Sakimura <sakim...@gmail.com
<mailto:sakim...@gmail.com>>
I am having trouble with the very first assumption. The
user-agent sets up a non TLS protected connection to the
RP? That’s a fundamental violation of 6749.
Also, the second statement says the RP (assuming it acts
as OAuth client) is talking to two IDPs. That’s still a
multi-AS case is it not?
Phil
@independentid
www.independentid.com
phil.h...@oracle.com
On Jan 25, 2016, at 2:58 PM, Nat Sakimura
<sakim...@gmail.com> wrote:
Hi Phil,
Since I was not in Darmstadt, I really do not know what
was discussed there, but with the compromised developer
documentation described in
http://nat.sakimura.org/2016/01/15/idp-mix-up-attack-on-oauth-rfc6749/,
all RFC6749 clients with a naive implementer will be
affected. The client does not need to be talking to
multiple IdPs.
Nat
2016 年1月26日(火) 3:58 Phil Hunt (IDM)
<phil.h...@oracle.com>:
I recall making this point in Germany. 99% of
existing use is fine. OIDC is probably the largest
community that *might* have an issue.
I recall proposing a new security document that
covers oauth security for dynamic scenarios.
"Dynamic" being broadly defined to mean:
* clients who have configured at runtime or install
time (including clients that do discovery)
* clients that communicate with more than one endpoint
* clients that are deployed in large volume and may
update frequently (more discussion of "public" cases)
* clients that are script based (loaded into
browser on the fly)
* others?
Phil
> On Jan 25, 2016, at 10:39, George Fletcher
<gffle...@aol.com> wrote:
>
> would
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