IETF 79 Proceedings

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Application Bridging for Federated Access Beyond web (abfab) (WG)

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Additional information is available at tools.ietf.org/wg/abfab

Chair(s): Klaas Wierenga Leif Johansson Security Area Director(s): Stephen Farrell Sean Turner Security Area Advisor: Stephen Farrell

Meeting Slides

• Note Well and Agenda
• Abfab Introduction
• ABFAB Architecture
• AAA Attribute for SAML
• EAP GSS Mechanism

Internet-Drafts:

• A GSS-API Mechanism for the Extensible Authentication Protocol (41926 bytes)
• A RADIUS Attribute for SAML Messages (9895 bytes)
• Application Bridging for Federated Access Beyond web (ABFAB) Use Cases (13332 bytes)

No Request For Comments

Charter (as of 2011-03-31)

Problem Statement

Federated identity facilitates the controlled sharing of information
about principals, commonly across organisational boundaries. This avoids
redundant registration of principals who operate in multiple domains,
reducing administrative overheads and improving usability while
addressing privacy-related concerns and regulatory and statutory
requirements of some jurisdictions. A number of such mechanisms are in
use for the Web. This working group will specify a federated identity
mechanism for use by other Internet protocols not based on HTML/HTTP,
such as for instance IMAP, XMPP, SSH and NFS. The design will combine
existing protocols, specifically the Extensible Authentication Protocol
(EAP - RFC 3748), Authentication, Authorization and Account Protocols
(RADIUS - RFC 2865 and Diameter - RFC 3588), and the Security Assertion
Markup Language (SAML).

Specifically EAP will be used to authenticate the subject to a trusted
party, AAA (RADIUS and Diameter) will be used to authenticate and convey
information from that party to a relying party and SAML and SAML message
formats are used to carry subject information that can be used for
authorization and personalization by a relying party. Any change in the
choices for these three technical roles is out of scope for this charter.

Constraints
-----------

Initially the working group will focus on using GSS-API (RFC2743) as a
mechanism for integrating the developed solution for federated identity
into application protocols but other technologies for application
interface are in scope of the working group and may be adopted as
deliverables subject to the normal IETF consensus and (re)charter
process.

In order to be usable in all current Internet protocols, GSS-API
mechanism must provide the following features: mutual authentication, key
confirmation, host-based service naming, per-message tokens ("security
layers") and channel binding. Support for Pseudo Random Function (PRF)
is desirable, and generally feasible whenever per-message tokens are
supported. As a result, all of those features are required for GSS-API
mechanisms produced by this WG. Note also that some of these
requirements derive from SASL (RFC 4422) applications, which can use GSS-
API mechanisms through GS2 (RFC5081).

Other application integration strategies are very likely to mirror these
constraints. In particular, host-based service naming, mutual
authentication and support for channel binding are likely to be important
for defense against phishing attacks.

The working group will ensure that any solution developed has technical
controls for privacy protection.

Other than a change to its applicability statement and the development of
EAP mechanisms, the working group may not change EAP, RADIUS or Diameter
without establishing consensus with the appropriate community within the
IETF.

The working group will use the following documents as a starting point
for its work:

- draft-howlett-eap-gss-00,
- draft-howlett-radius-saml-attr-00
- draft-hartman-gss-eap-naming-00

Concerns have been raised that additional work is required in keying AAA
associations in a federated environment. The working group is chartered
to explore these concerns and if needed, specify protocols that use
existing AAA key management mechanisms to address these concerns.

Coordination with other SDOs
----------------------------

The Working Group will work in conjunction with the IAB to establish
appropriate liaison relationships with the OASIS Security Services
Technical Committee (SSTC) and take care that any changes or profiling
required in SAML can be properly coordinated across the different
organizations.

In particular coordination is required with respect to the SAML-RADIUS
binding.

Deliverables
------------

1. Descriptions of applicable use cases (informational).

2. An architecture that describes how the components of the solution fit
together to address the use cases and open issues that will require
future changes to the architecture (informational).

3. A standards-track update to the EAP applicability statement in RFC
3748 describing the applicability of EAP to application authentication
and placing appropriate requirements on this new EAP use case.

4. A standards-track solution for using EAP methods to provide
authentication within the application.

5. A standards-track update to the EMSK root key applicability statement
in RFC 5295.

6. A standards-track description of GSS names and name attributes
required by the solution.

7. Descriptions of usability and user-interface concerns related to this
work (informational).

8. A standards-track protocol for carrying SAML messages in RADIUS and
Diameter.

Goals and Milestones:

Oct 2010		Submit Internet draft describing applicable use cases as initial WG item.
Oct 2010		Submit Internet draft describing the architecture as initial WG item.
Oct 2010		Submit Internet draft that updates the EAP applicability statement as initial WG item.
Oct 2010		Submit Internet draft for using EAP methods to provide authentication within the application as initial WG item.
Oct 2010		Submit Internet draft that updates the EMSK root key applicability statement as initial WG item.
Oct 2010		Submit Internet draft that describes GSS names and name attributes as initial WG item.
Oct 2010		Submit Internet draft for usability and user-interface concerns as initial WG item.
Oct 2010		Submit Internet draft for SAML messages in Radius and Diameter as an initial WG item.
Dec 2010		Submit Internet draft describing applicable use cases to the IESG for consideration.
Dec 2010		Submit Internet draft describing the architecture to the IESG for consideration.
May 2011		Submit Internet draft that updates the EAP applicability statement to the IESG for consideration.
May 2011		Submit Internet draft for using EAP methods to provide authentication within the application to the IESG for consideration.
Aug 2011		Submit Internet draft that updates the EMSK root key applicability statement to the IESG for consideration.
Aug 2011		Submit Internet draft that describes GSS names and name attributes to the IESG for consideration.
Aug 2011		Submit Internet draft for usability and user-interface concerns to the IESG for consideration.
Dec 2011		Submit Internet draft for SAML messages in Radius and Diameter to the IESG for consideration.