> It is fair to say that the threats and mitigations from bearer tokens also
> apply to PoP tokens.> PoP tokens add additional key information that must
> also be protected along with the other > information in a access token.
THis doesn't really work because for example transport security to protect the
token itself is part of the Bearer security considerations and PoP tokens are
making that much less of a problem. I don't know if there's more but that
doesn't work. Referencing specific things from Bearer and not the whole
secuiryt considerations section could work.
On Wednesday, November 25, 2015 12:55 PM, John Bradley <[email protected]>
wrote:
I have been assuming that security considerations from RFC 6750 would be
applied to “PoP” tokens as well when the tokens presentment/confirmation specs
are done.
Sec 5.2 of RFC 6750 covers mitigations for modification and manufacture for by
value and by reference tokens.
Do we want to keep repeating this information in all documents or reference it?
It is fair to say that the threats and mitigations from bearer tokens also
apply to PoP tokens.PoP tokens add additional key information that must also be
protected along with the other information in a access token.
John B.
On Nov 25, 2015, at 5:39 PM, Kathleen Moriarty
<[email protected]> wrote:
Hi,
Sent from my iPhone
On Nov 25, 2015, at 3:20 PM, John Bradley <[email protected]> wrote:
Tokens are signed or the information is otherwise integrity protected between
the AS and the RS.
I suspect Kathleen is concerned about the key getting modified in transit.
That needs to be protected against, but there is more than one way to do that.
Phil is correct. I was looking for consistency between the sections since they
related to each other. If there is a security risk or consideration, that
needs to be explicitly called out as a concern such as a key being modified in
transit. If there are options to protect against that, those would ideally be
required or would have warnings.
So sending the public key in a unsigned JWT access token would be immensely
stupid, not just for PoP but for scopes and everything else.
Good, easy to require then.
Thanks,Kathleen
In OAuth 2 all tokens need to be integrity protected between the AS and RS.
That can be via signature, by having a reference with sufficient entropy and
secure introspection or database lookup.
I think that is a OAuth 2 security consideration. We are adding a additional
confirmation claim to the existing information that needs to be protected the
same as the rest.
John B.
On Nov 25, 2015, at 4:38 PM, Phil Hunt <[email protected]> wrote:
<editors hat>If there is agreement that tokens are opaque then the requirement
that tokens be signed must be removed from the threat mitigation requirements.
And the paragraph in sec 5 that brian was concerned about be restored.
Phil
On Nov 25, 2015, at 11:24, Justin Richer <[email protected]> wrote:
It is still end to end authentication with opaque tokens — since all OAuth
tokens, including PoP tokens, have always been intended to be opaque to the
client. That hasn’t changed and that isn’t the intent of this document. If
that’s how people are reading it then we need to pull it back and rewrite it so
that’s not the case.
The client gets a token that has two parts: the token and the key. The token is
analogous to the access_token we have today and would come out of the server in
the same field. The key is handed to the client alongside the token or
registered by the client during the token request. Either way there’s an
association between the two but it’s not the same association as a
public/private keypair.
It’s possible to sign the token itself, but the client doesn’t care. It sends
the token and signs the HTTP request to the RS whether the token is signed,
unsigned, hex blob, encrypted, or anything else. The same series of options are
available as with bearer tokens. PoP tokens have never, ever been intended to
be anything but opaque to the client.
The token can’t be opaque to the RS, which has to figure out what key to use to
check the message signature. But we’ve got options there, like the embedded key
in a JWT from Mike’s draft, or doing introspection to get the key (from an
extension that hasn’t been written yet), or simply looking it up in the same
database because the RS and the AS are in the same box. Does this
structure/service/database choice sound familiar? It should, it’s the same as
bearer tokens. This is also how the RS gets information like which scopes are
associated with the token, if it’s expired, and all that.
So here’s how I see it going on the wire:
(I just wrote this up so there are probably holes. Here’s the source if anyone
wants to tweak it:
http://www.websequencediagrams.com/?lz=cGFydGljaXBhbnQgQ2xpZW50IGFzIEMKAAwMUmVzb3VyY2UgT3duZXIgYXMgUk8AFA1BdXRob3JpemF0aW9uIFNlcnYAIQZBUwA7DVByb3RlY3RlZABICmFzIFJTCgoKClJPLS0-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&s=modern-blue
)
The client is oblivious to the token just like always. This is intentional. The
RS has the same options to figure out how to process the token.
— Justin
On Nov 25, 2015, at 2:03 PM, Phil Hunt <[email protected]> wrote:
Folks,
<editor hat>I did not want to go here either. :-)
I don’t read sec 6 as examples. I believe this may stem from the
pop-architecture documents having a dual role as both “architecture” and
“use-case”. Maybe we should clarify the purpose of the document?
I believe section 6 is talking about threat mitigation assumptions based on the
examples that need to be implemented. I am assuming these are requirements
that the other specifications SHOULD implement.
<personal hat>I do not believe we have discussed Opaque PoP tokens and any
inherent risks because the client is not or is unable to validate the
authenticity of the token. Does this introduce the possibility of a MITM
attack where a client can be convinced to sign requests for an attacker?
If we want to include opaque PoP, I think we need to take a pause and consider
/ discuss any threats here.
I find the desire for opaque PoP tokens to be a bit contradictory. If we’re
saying we don’t want to trust TLS alone (e.g. because of load-balancer
termination), why would we then say, but we are perfectly willing to accept it
worked for the OAuth AS exchanges? Maybe I was very wrong here, but my
assumption all along is that for PoP we’re talking about end-to-end
authentication of all parties except in the case of 3.3 where we simply want to
protect an access token over a non-TLS HTTP connection.
Phil
@[email protected]
On Nov 25, 2015, at 10:48 AM, Brian Campbell <[email protected]> wrote:
While I can't say I disagree with the deeper existential questions about the
draft that Justin raises, I was trying not to go there and rather just point
out concerns with the newly added text.
The text Phil cites from Sec 6 doesn't say the client must be able to parse and
verify the token. It's an assumption to simplify the examples that follow and
still the token is opaque to the client. I reread the whole draft (reluctantly)
and there's nothing that says the token has to be non-opaque to the client. And
it does talk about reference style tokens and encrypted tokens, both of which
rely on the opaqueness to the client.
On Wed, Nov 25, 2015 at 11:27 AM, Justin Richer <[email protected]> wrote:
Right, I read that as text for describing the examples and not for describing
requirements.
The token itself doesn’t have to be signed at all.
— Justin
On Nov 25, 2015, at 1:05 PM, Phil Hunt <[email protected]> wrote:
Ok. Well this was requested by Kathleen because of this paragraph in Sec 6.…
To simplify the subsequent description we assume in the PoP architecture
that the token itself is digitally signed by the authorization server
and therefore cannot be modified.
Please Phil
@[email protected]
On Nov 25, 2015, at 9:33 AM, Justin Richer <[email protected]> wrote:
The token doesn’t have to be signed and the client doesn’t have to verify the
signature on the token. That’s not PoP. The request has to be signed in a way
that includes the token. The token itself can still be opaque. The *key*
material can’t be opaque to the client, but the *token* material still is.
I agree with Brian that this statement is misleading.
The examples use a signed token but that is absolutely not a requirement. Maybe
the examples shouldn’t all use one style.
What’s most difficult about this particular spec is that it’s very hand-wavy,
saying “this is kinda a thing that kinda works like this” without saying how to
actually do it. I’m honestly not sure it’s worth publishing as an RFC in its
own right but I’m not going to stand in its way.
— Justin
On Nov 25, 2015, at 12:14 PM, Brian Campbell <[email protected]> wrote:
Where does it say that?
On Wed, Nov 25, 2015 at 8:44 AM, Phil Hunt <[email protected]> wrote:
Except that later on we require the token be signed and the client verify that
signed token. IOW mutual pop.
Phil
On Nov 25, 2015, at 07:30, Brian Campbell <[email protected]> wrote:
Looking at the diff I noticed the following new text, which seems to conflate
bearer/PoP and opaqueness to the client. A client demonstrating
proof-of-possession of some key is orthogonal to the client being able to parse
and understand the access token itself.
"In contrast to bearer tokens [RFC6750] which call for tokens that are opaque
to OAuth 2.0 clients, this specification defines the requirements for
proof-of-possession ("PoP") tokens that may be parsed and verified by OAuth 2.0
clients and relying parties."
On Tue, Nov 24, 2015 at 1:07 PM, Phil Hunt <[email protected]> wrote:
This draft addresses review comments from Kathleen and Erik raised since the
last draft.
It may not include some of the discussion from yesterday/today. I will add
that as the group decides.
Cheers,
Phil
@independentid
www.independentid.com
[email protected]
> On Nov 24, 2015, at 12:05 PM, [email protected] wrote:
>
>
> A New Internet-Draft is available from the on-line Internet-Drafts
> directories.
> This draft is a work item of the Web Authorization Protocol Working Group of
> the IETF.
>
> Title : OAuth 2.0 Proof-of-Possession (PoP) Security
>Architecture
> Authors : Phil Hunt
> Justin Richer
> William Mills
> Prateek Mishra
> Hannes Tschofenig
> Filename : draft-ietf-oauth-pop-architecture-06.txt
> Pages : 23
> Date : 2015-11-24
>
> Abstract:
> The OAuth 2.0 bearer token specification, as defined in RFC 6750,
> allows any party in possession of a bearer token (a "bearer") to get
> access to the associated resources (without demonstrating possession
> of a cryptographic key). To prevent misuse, bearer tokens must be
> protected from disclosure in transit and at rest.
>
> Some scenarios demand additional security protection whereby a client
> needs to demonstrate possession of cryptographic keying material when
> accessing a protected resource. This document motivates the
> development of the OAuth 2.0 proof-of-possession security mechanism.
>
>
> The IETF datatracker status page for this draft is:
> https://datatracker.ietf.org/doc/draft-ietf-oauth-pop-architecture/
>
> There's also a htmlized version available at:
> https://tools.ietf.org/html/draft-ietf-oauth-pop-architecture-06
>
> A diff from the previous version is available at:
> https://www.ietf.org/rfcdiff?url2=draft-ietf-oauth-pop-architecture-06
>
>
> Please note that it may take a couple of minutes from the time of submission
> until the htmlized version and diff are available at tools.ietf.org.
>
> Internet-Drafts are also available by anonymous FTP at:
> ftp://ftp.ietf.org/internet-drafts/
>
> _______________________________________________
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> https://www.ietf.org/mailman/listinfo/oauth
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| | +1 720.317.2061 |
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--
| | Brian Campbell
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| @ | [email protected] |
| | +1 720.317.2061 |
| | @pingidentity |
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|
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| | Brian Campbell
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Ping Identity
| @ | [email protected] |
| | +1 720.317.2061 |
| | @pingidentity |
| Connect with us! |
| |
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