Hi Mohit, all,
I have a question for you - in which sense you mean "prudent" ?
Are you saying that creating "general-use" credentials or provisioning
credentials is different ? Creating "general-use" credentials instead of
provisioning/managing the Access Network credentials seems way more
scary and generic than the text I proposed (which limits the scope of
the credentials you should manage with EAP to the credentials that are
used to access the network), therefore, because of your comment, I would
like to have some clarifications here because my interpretation could be
different than yours... and, based on that, my "happiness" level can be
different than initially reported :D
In particular, I would like to understand if the following operations
can be supported by an EAP method:
* Renewing Existing credentials (i.e., maybe credentials that were
generated via the EAP method in the first place)
* Removing Existing credentials (i.e., the network will not use that
credential anymore, therefore it tasks the device to remove them)
Personally, for the work we are doing in different types of Access
Networks (3gpp, CBRS-A, WiFi / WFA, and DOCSIS(r)), I think that the
advantage of the EAP method is about managing the credentials that are
also consumed by the EAP framework - I would not let my
application-layer credentials be managed by the Access Network... and
the opposite should apply as well, IMHO.
/*As long as both views are supported, I am ok with the text. */
However, if your interpretation of the charter would not allow
operations like registering an existing long-term credential to access
the network (e.g., the device cannot generate/use a different one),
renewing the credentials used to access the network, or
deleting/removing/revoking existing credentials (i.e., no need to keep a
private key or secrets around if it is not useful), then I would not be
happy with the text.
Can you please provide clarifications on the above points ?
Also, you mention that there is an IESG meeting on October 31st - is it
possible to participate to that meeting ? If so, can you please let us
know the meetings' details... ?
Last but not least - I sent you the request earlier for a slot at IETF
106 for EAP-CREDS and I would like to confirm again with you we have the
slot (I do not recall seeing your reply to that message).
Cheers,
Max
On 10/15/19 2:07 AM, Mohit Sethi M wrote:
Dear Dr. Pala,
I think we need to be more prudent when using terms such as
"credential provisioning" and "credential management". The bullet
later on in the current charter text specifically says that the
credentials are for the EAP peer:
|Define mechanisms by which EAP methods can support creation of
long-term credentials for the peer based on initial limited-use
credentials.|
Given that you are happy with the current text, I have a preference to
leave it in its current form. We are hoping that the IESG will discuss
this in their telechat on 31 October (which is also the last chance
before Singapore).
--Mohit
On 10/15/19 3:11 AM, Dr. Pala wrote:
Hi Mohit, all,
sorry for the long delay in replying (probably mute at this point),
however I think the new text looks great. The only possible change I
would provide is the possibility to restrict the scope for the
credentials management part. In particular, I would change the following:
The group will investigate minimal mechanisms with which
limited-use EAP authentication credentials can be used for
creating general-use long-term credentials.
With something scoped to the credentials for accessing the network
itself (instead of a generic credentials provisioning mechanism):
The group will investigate minimal mechanisms to manage long-term
credentials that are use to access the network.
This would probably make the management of credentials scoped to
providing and managing the access credentials that the network is
authoritative for - I would feel a bit "un-ease" to provide
mechanisms to provision credentials to be used outside the access
network context (just because it might not be the best enforcement
point).
Given that I would be happier with a reduced scope (unless there are
good reasons not to limit the scope), I am also happy with the
current text (since allows EAP-CREDS to be discussed).
Thanks,
Max
On 9/21/19 6:16 AM, Mohit Sethi M wrote:
Hi Georgios,
Thanks for reading the charter. I have addressed your comments on
github. Here is the updated text:
https://github.com/emu-wg/charter/blob/master/emu-charter.md
and here is the diff from the previous version:
https://github.com/emu-wg/charter/commit/be1bf557355ecba5d5ee35ab27f3e8fae8c06eef
--Mohit
On 9/18/19 11:37 AM, Georgios Z. Papadopoulos wrote:
Dear Joe, Mohit and all,
In overall I find the text well written, while the objectives well
defined.
Below I have very few comments :
* TLS is not defined.
* Perfect Forward Secrecy (PFS) is defined twice.
* - An update to enable the use of TLS 1.3 in the context of
EAP-TLS (RFC 5216). */This document will pdate the security
considerations relating to EAP-TLS, document the implications of
using new vs. old TLS versions, add any recently gained new
knowledge on vulnerabilities, and discuss the possible implications
of pervasive surveillance./*
This last point, maybe could be divided in several sentences, since
I find it too long and, thus, hard to follow.
Many thanks for your efforts.
Best regards,
Georgios
On Sep 11, 2019, at 20:50, Mohit Sethi M
<mohit.m.se...@ericsson.com <mailto:mohit.m.se...@ericsson.com>>
wrote:
Dear all,
Please send in your comments on the charter text by Wednesday,
September 18, 2019.
Joe and Mohit
On 8/21/19 11:13 AM, Mohit Sethi M wrote:
Dear all,
Thank you for a productive meeting @ IETF 105. We had discussed
the new charter text during the working group session in
Montreal. Please find the same text below. This text builds upon
our current charter. Feel free to suggest changes. RFC 2418
section 2.2 https://tools.ietf.org/html/rfc2418#section-2.2 says
the following about a working group charter:
2. Specifies the direction or objectives of the working group and
describes the approach that will be taken to achieve the goals;
Please keep this in mind when suggesting changes. Once the text
is ready, we will send it to the IESG for review.
Joe and Mohit
------------------------
The Extensible Authentication Protocol (EAP) [RFC 3748] is a
network access authentication framework used, for instance, in
VPN and mobile networks. EAP itself is a simple protocol and
actual authentication happens in EAP methods. Several EAP methods
have been developed at the IETF and support for EAP exists in a
broad set of devices. Previous larger EAP-related efforts at the
IETF included rewriting the base EAP protocol specification and
the development of several standards track EAP methods.
EAP methods are generally based on existing security technologies
such as TLS and SIM cards. Our understanding of security threats
is continuously evolving. This has driven the evolution of
several of these underlying technologies. As an example, IETF has
standardized a new and improved version of TLS in RFC 8446. The
group will therefore provide guidance and update EAP method
specifications where necessary to enable the use of new versions
of these underlying technologies.
At the same time, some new use cases for EAP have been
identified. EAP is now more broadly in mobile network
authentication. The group will update existing EAP methods such
as EAP-AKA' to stay in sync with updates to the referenced 3GPP
specifications. RFC 7258 notes that pervasive monitoring is an
attack. Perfect Forward Secrecy (PFS) is an important security
property for modern protocols to thwart pervasive monitoring. The
group will therefore work on an extension to EAP-AKA' for
providing Perfect Forward Secrecy (PFS).
Out-of-band (OOB) refers to a separate communication channel
independent of the primary in-band channel over which the actual
network communication takes place. OOB channels are now used for
authentication in a variety of protocols and devices
(draft-ietf-oauth-device-flow-13, WhatsApp Web, etc.). Many users
are accustomed to tapping NFC or scanning QR codes. However, EAP
currently does not have any standard methods that support
authentication based on OOB channels. The group will therefore
work on an EAP method where authentication is based on an
out-of-band channel between the peer and the server.
EAP authentication is based on credentials available on the peer
and the server. However, some EAP methods use credentials that
are time or domain limited (such as EAP-POTP), and there may be a
need for creating long term credentials for re-authenticating the
peer in a more general context. The group will investigate
minimal mechanisms with which limited-use EAP authentication
credentials can be used for creating general-use long-term
credentials.
In summary, the working group shall produce the following documents:
- An update to enable the use of TLS 1.3 in the context of
EAP-TLS (RFC 5216). This document will pdate the security
considerations relating to EAP-TLS, document the implications of
using new vs. old TLS versions, add any recently gained new
knowledge on vulnerabilities, and discuss the possible
implications of pervasive surveillance.
- Several EAP methods such EAP-TTLS and EAP-FAST use an outer
TLS tunnel. Provide guidance or update the relevant
specifications explaining how those EAP methods (PEAP/TTLS/TEAP)
will work with TLS 1.3. This will also involve maintenance work
based on erratas found in published specifications (such as
EAP-TEAP).
- Define session identifiers for fast re-authentication for
EAP-SIM, EAP-AKA, and EAP-AKA’. The lack of this definition is a
recently discovered bug in the original RFCs.
- Update the EAP-AKA' specification (RFC 5448) to ensure that its
capability to provide a cryptographic binding to network context
stays in sync with updates to the referenced 3GPP specifications.
The document will also contain any recently gained new knowledge
on vulnerabilities or the possible implications of pervasive
surveillance.
- Develop an extension to EAP-AKA' such that Perfect Forward
Secrecy can be provided. There may also be privacy improvements
that have become feasible with the introduction of recent
identity privacy improvements in 3GPP networks.
- Gather experience regarding the use of large certificates and
long certificate chains in the context of EAP-TLS (all versions),
as some implementations and access networks may limit the number
of EAP packet exchanges that can be handled. Document operational
recommendations or other mitigation strategies to avoid issues.
- Define a standard EAP method for mutual authentication between
a peer and a server that is based on an out-of-band channel. The
method itself shall be independent of the underlying OOB channel
and shall support a variety of OOB channels such as NFC,
dynamically generated QR codes, audio, and visible light.
- Define mechanisms by which EAP methods can support creation of
long-term credentials for the peer based on initial limited-use
credentials.
The working group is expected to stay in close collaboration with
the EAP deployment community, the TLS working group (for EAP-TLS
work), and the 3GPP security architecture group (for EAP-AKA' work)
------------------------
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Best Regards,
Massimiliano Pala, Ph.D.
OpenCA Labs Director
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