Re: [Emu] Re-charter text

["Dr. Pala" <[e-mail]>]

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 <[e-mail] 
>>> <mailto:[e-mail]>> 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 
>>>> <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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