RE: [Nea] WG Review: Network Endpoint Assessment (nea)

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Hi Vidya

Thanks for your comments.

Inline ...

> -----Original Message-----
> From: Narayanan, Vidya [mailto:vidyan@xxxxxxxxxxxx] 
> Sent: Wednesday, October 04, 2006 12:48 PM
> To: iesg@xxxxxxxx
> Cc: nea@xxxxxxxx
> Subject: RE: [Nea] WG Review: Network Endpoint Assessment (nea) 
> 
> 
> All,
> Comments on the charter inline below.  
> 
> > -----Original Message-----
> > From: IESG Secretary [mailto:iesg-secretary@xxxxxxxx] 
> > Sent: Monday, October 02, 2006 7:30 AM
> > To: ietf-announce@xxxxxxxx
> > Cc: nea@xxxxxxxx
> > Subject: [Nea] WG Review: Network Endpoint Assessment (nea) 
> > 
> > A new IETF working group has been proposed in the Security Area.  
> > The IESG has not made any determination as yet. The following 
> > draft charter was submitted, and is provided for 
> > informational purposes only.
> > Please send your comments to the IESG mailing list 
> > (iesg@xxxxxxxx) by October 9.
> > 
> > +++
> > 
> > Network Endpoint Assessment (nea)
> > ======================================
> > 
> > Current Status: Proposed Working Group
> > 
> > Chair(s): 
> > TBD
> > 
> > Security Area Director(s):
> > Russ Housley <housley@xxxxxxxxxxxx>
> > Sam Hartman <hartmans-ietf@xxxxxxx>
> > 
> > Security Area Advisor:
> > Russ Housley <housley@xxxxxxxxxxxx>
> > 
> > Mailing List: nea@xxxxxxxx
> > 
> > Description of Working Group:
> > 
> > Network Endpoint Assessment (NEA) architectures have been 
> > implemented in the industry to assess the "posture" of 
> > endpoint devices for the purposes of monitoring compliance to 
> > an organization's posture policy and optionally restricting 
> > access until the endpoint has been updated to satisfy the 
> > posture requirements. An endpoint that does not comply with 
> > posture policy may be vulnerable to a number of known threats 
> > that may exist on the network. The intent of NEA is to 
> > facilitate corrective actions to address these known 
> > vulnerabilities before a host is exposed to potential attack.
> 
> 
> Is it fair to then say that NEA is attempting to protect the 
> endhost and
> not necessarily the network? 

Yes, this is the focus. 

> That is not immediately clear in the
> charter. Obviously, the network must deal with all kinds of known and
> unknown threats and a process like NEA is inadequate to protect it at
> any acceptable level. That is why we employ a number of other 
> mechanisms
> like firewalls, access control, packet filters, IDS/IPS, etc. in any
> combination to appropriately protect the networks. 
> 
> So, stating that NEA is not attempting to protect the network at large
> would bring a lot of clarity to the charter. 
> 

Since we have been around the block  a few times on this section, could
you suggest precise text that you would like to see to make this
clearer?  

> 
> > Two deployment scenarios will be supported: advisory mode and 
> > mandatory mode.
> > In advisory mode, an endpoint may be advised of the result of 
> > posture assessment and any recommended remediation actions, 
> > but is provided normal network access regardless of the 
> > result. In mandatory mode, a non-compliant endpoint is given 
> > restricted access to the network sufficient for remediation 
> > purposes and any essential services or denied access completely.
> > 
> 
> It is unclear how the advisory vs mandatory model relates to the NEA
> procedures itself. NEA is attempting to provide a vehicle to perform
> some compliance tests on acceptable "postures". What the 
> network decides
> to do with that information seems entirely dependent on the policy of
> the network and the extent of non-compliance, etc. What does 
> it mean to
> say that NEA *allows* an advisory and/or a mandatory model? 
> 
> 
Yes, it is a matter of policy. We have had other input as well that
indicates this text is causing confusion.  We added this text in
consultation with our AD to re-inforce the notion that NEA did not
necessarily imply enforcement, and that things like
emergency services could be made available regardless of the outcome of
posture assessment.

The intention is not to be prescriptive about an organization's policy
in any way.

Bearing the original motivation in mind, would the following work
better?
"An organization may make a range of policy decisions based on the
posture of an endpoint. NEA is not intended to be prescriptive in this
regard. For example, 
potential deployment scenarios may include,but are not  limited to, 
providing normal access regardless of compliance
with recommendations for remediation ("advisory mode"), as well as
providing restricted access sufficient for remediation purposes and
any essential services until an endpoint is in compliance ("mandatory
mode"). 

> > Posture refers to the hardware or software configuration of 
> > an endpoint as it pertains to an organization's security 
> > policy. Posture may include knowledge that software installed 
> > to protect the machine (e.g. patch management software, 
> > anti-virus software, host firewall software, host intrusion 
> > protection software or any custom software) is enabled and 
> up-to-date.
> > On network access and while connected, an endpoint supporting 
> > NEA protocols can be queried for such posture information in 
> > either advisory or mandatory modes.
> > 
> 
> Again, what does it mean to be queried in a particular mode? 
> 

Based on consensus re the above, reference to the "modes" may be able to
be dropped.

> > Since NEA involves many different components from different 
> > vendors, interoperation
> 
> s/interoperation/interoperability
> 

OK.

> > is highly desirable. The priority of 
> > the NEA working group is to standardize protocols at the 
> > higher layers in the architectures:
> > the Posture Attribute protocol (PA) and the Posture Broker 
> > protocol (PB).
> > PA and PB will be designed to support a variety of lower 
> > layer protocols.
> > When used with standards for lower layers, these new 
> > protocols will allow interoperability between an NEA Client 
> > from one vendor and an NEA Server from another.
> > 
> 
> This seems like an optimistic goal. Given that only a subset of
> attributes are envisioned to be standardized and given that 
> the kind of
> attributes are likely to be ever increasing, considering that posture
> refers to hardware/software configuration of an endpoint, I 
> fail to see
> how we would practically get NEA clients and NEA servers from 
> different
> vendors to perform any meaningful NEA procedures. In theory, I can see
> how this can be slated to be a goal - but, I have to believe that
> reality would be different. 
> 

This was discussed at last BOF, and resolution was to require that
vendor-specific attributes be documented in a RFC. 

Its also possible that components of a client and  components of a
server are provided by same or different vendors, i.e. interoperability
is not necessarily an all or nothing proposition. 

> 
> > Since there are already several non-standard protocols at 
> > these higher layers, the NEA working group will consider 
> > these existing protocols as candidates for standardization. A 
> > requirements document will be written and used as a basis for 
> > evaluating the candidate protocols.
> > The working group may decide to standardize one of the 
> > candidate protocols, use one of them as a basis for a new or 
> > revised protocol, or decide that a new protocol is needed.
> > 
> > The NEA Requirements document will include a problem 
> > statement, definition of terms, requirements for the PA and 
> > PB protocols, and an overall security analysis. It will also 
> > include generic requirements for the protocol transporting 
> > PA, PB: the Posture Transport protocol (PT). PT protocols may 
> > be standardized in other WGs since these protocols may not be 
> > specific to NEA. The NEA WG will identify one mandatory to 
> > implement PT protocol to ensure interoperability.
> > 
> 
> I assume that the mandatory to implement PT protocol must satisfy the
> criteria that will allow the NEA process to be triggered at any time
> (i.e., during or after network access). Clarifying this would 
> be good. 
> 

There is text in a few paragraphs above that says "on network access and
while connected, an endpoint supporting NEA protocols can be queried for
such posture information". Is this not sufficient?

> 
> > PA, the Posture Attribute protocol, consists of posture 
> > attributes that are carried between a particular Posture 
> > Collector in a NEA client and a particular Posture Validator 
> > in a NEA Server. The PA protocol is carried inside the PB 
> > protocol. Certain posture attributes will be standardized to 
> > ensure interoperability but vendor-specific attributes will 
> > also be supported. Vendor-specific attributes must be 
> > documented in an RFC.
> > 
> 
> This goes back to my comment on interoperability. Unless it 
> is expected
> that there will be ongoing efforts to continually standardize 
> attributes
> of significance to the community as the hardware/software 
> configurations
> of devices evolve, I am afraid that we won't have interoperability of
> any significance. 
> 

Ongoing standardization of attributes can be done as necessary. 

> 
> > The PB (Posture Broker) protocol aggregates posture 
> > attributes from one or more Posture Collectors in an NEA 
> > client and sends them to the NEA server for assessment by one 
> > or more Posture Validators.
> > 
> > The PT (Posture Transport) protocol (or stack of protocols) 
> > is suitable for carrying the PB protocol at the time of 
> > network connection, or shortly after.
> > 
> > The NEA working group will not specify protocols other than 
> > PA and PB at this time. The expectation is that an existing 
> > protocol can be used for the PT.
> > 
> > 
> > One commonly discussed issue with NEA systems is how to 
> > handle compromised endpoints, whose reports of their own 
> > posture may not be accurate. Detecting or handling such 
> > endpoints is out of scope of the NEA WG. Work on PA will 
> > focus on attributes useful for assessing posture of those 
> > endpoints reporting accurate information. However, the 
> > protocols developed by the NEA WG must be designed to 
> > accommodate emerging technologies for identifying and dealing 
> > with lying endpoints.
> > 
> 
> 
> I'm not sure what the last sentence means here - everything in this
> paragraph alludes to the fact that lying endpoints are out of 
> scope. If
> the last sentence is alluding to the TCG efforts, why is it 
> cryptic? As
> currently stated, it doesn't seem to add any value. If we say that in
> order for NEA to have a meaningful use case, it must work 
> together with
> some of the TCG stuff, then, perhaps that is effort that the WG must
> ensure gets done. 
> 

The last sentence was added as a result of the consensus reached at the
last BOF. The intent is to make sure that NEA is compatible with
emerging technologies to address "lying endpoints" so that they can be
used together if a user chooses to do so. 

TCG is one example that could place requirements on NEA to ensure
compatibility, but need not be the only one. My understanding (although
I am no expert) is that requirements include providing a multi-round
sequenced message exchange with authentication of the server,
confidentiality, and integrity protection. Such requirements are not
expected to be onerous. 

> 
> > Note that NEA is not chartered to standardize protocols for 
> > remediation.
> > NEA is intended to be used with new or existing tools that 
> > can be used in the absence of NEA. There is an open issue 
> > with respect to NEA applicability in deployment scenarios 
> > where the endpoint is owned by a party that is different from 
> > the organization providing network access.
> > 
> 
> 
> Why is this an open issue? When the endpoint and the organization
> providing network access are owned by different parties, it 
> simply does
> not seem to be viable to do any kind of configuration 
> assessment on the
> endpoint. I think this should be stated rather clearly along these
> lines: 
> 
> "NEA is limited in applicability to the case where the 
> endpoint is owned
> by the organization providing network access and performing the
> assessment. In the cases where the two belong to a different party, it
> is practically infeasible for an organization providing network access
> to perform any kind of posture assessment or related 
> compliance tests on
> the endpoint."
> 

The reason we left it open is to allow the working group to spend more
time exploring the range of use cases in this area to better determine
requirements and applicability. For example, it may be useful to
classify endpoints as network-managed versus user-managed versus
3rd-party managed. A user-managed endpoint may want the choice to opt in
or opt out, say.

Thanks
Susan

> Thanks,
> Vidya
> 
> 
> > Further work in the NEA WG will be considered via the 
> > standard rechartering process after the completion of these 
> > milestones.
> > 
> > Milestones:
> > 
> > June 2006:
> > * Submit first version of NEA Requirements I-D
> > 
> > July 2006:
> > * Agree on charter and milestones at IETF 66
> > 
> > October 2006:
> > * Submit first draft of NEA Requirements I-D
> > 
> > November 2006:
> > * At IETF 67, discuss issues with NEA Requirements I-D
> > * Agree on solutions to issues with NEA Requirements I-D
> > 
> > December 2006:
> > * Deadline for submission of candidate specs for PA and PB
> > * Submit first version of NEA Evaluation I-D
> > 
> > January 2007:
> > * WG Last Call on NEA Evaluation I-D
> > 
> > February 2007:
> > * Submit NEA Requirements I-D and Evaluation I-D to IESG as Info RFC
> > * Submit first draft of PA and PB specs for review
> > 
> > March 2007:
> > * Discuss unresolved issues with PA and PB specs at IETF 68
> > * Agree on solutions to unresolved issues with PA and PB specs
> > 
> > April 2007:
> > * Submit revised draft of PA and PB specs
> > 
> > June 2007
> > * WG Last Call on PA and PB specs
> > 
> > July 2007
> > * Resolve outstanding WGLC comments on PA and PB specs at IETF 69
> > 
> > August 2007:
> > * Submit PA and PB specs to IESG for publication as Proposed
> > 
> > September 2007:
> > * Decide how to address MTI PT, recharter if needed
> > 
> > _______________________________________________
> > Nea mailing list
> > Nea@xxxxxxxx
> > https://www1.ietf.org/mailman/listinfo/nea
> > 
> 
> _______________________________________________
> Nea mailing list
> Nea@xxxxxxxx
> https://www1.ietf.org/mailman/listinfo/nea
> 

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