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Differences from draft-thomson-nea-problem-statement-00.txt





Network Working Group                                           S. Hanna
Internet-Draft                                          Juniper Networks
Expires: September 5, 2006                                   T. Hardjono
                                                           Signacert Inc
                                                             S. Thomson
                                                           Cisco Systems
                                                           March 4, 2006


          Network Endpoint Assessment (NEA) Problem Statement
               draft-thomson-nea-problem-statement-01.txt

Status of this Memo

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   This Internet-Draft will expire on September 5, 2006.

Copyright Notice

   Copyright (C) The Internet Society (2006).

Abstract

   Architectures have been implemented in the industry to assess the
   software or hardware configuration of endpoint devices for the
   purposes of monitoring or enforcing compliance of endpoints to an
   organization's policy on access to the network.  These architectures
   are not fully interoperable since some of the protocols used to



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   implement the architecture are not standards.

   This document describes the problem these architectures are intending
   to address, defines common terminology and concepts, and identifies
   interfaces that are candidates for standardization.


Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].







































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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  4
   3.  Problem Statement  . . . . . . . . . . . . . . . . . . . . . .  5
   4.  Goals  . . . . . . . . . . . . . . . . . . . . . . . . . . . .  6
   5.  Deployment Scenarios . . . . . . . . . . . . . . . . . . . . .  7
     5.1.  Wired LAN access . . . . . . . . . . . . . . . . . . . . .  7
     5.2.  Wireless LAN Access  . . . . . . . . . . . . . . . . . . .  7
     5.3.  Remote access VPN  . . . . . . . . . . . . . . . . . . . .  8
     5.4.  Gateway Access . . . . . . . . . . . . . . . . . . . . . .  8
   6.  Components and Interfaces  . . . . . . . . . . . . . . . . . .  8
     6.1.  Mapping to existing architectures  . . . . . . . . . . . .  9
     6.2.  Components . . . . . . . . . . . . . . . . . . . . . . . . 10
       6.2.1.  NEA Client . . . . . . . . . . . . . . . . . . . . . . 10
       6.2.2.  Network enforcer . . . . . . . . . . . . . . . . . . . 11
       6.2.3.  NEA server . . . . . . . . . . . . . . . . . . . . . . 12
     6.3.  Interfaces . . . . . . . . . . . . . . . . . . . . . . . . 13
       6.3.1.  Posture Attribute interface (IF-PA)  . . . . . . . . . 13
       6.3.2.  Posture Broker Interface (IF-PB) . . . . . . . . . . . 13
       6.3.3.  Posture Transport Interface (IF-PT)  . . . . . . . . . 13
       6.3.4.  Network Access Enforcement Interface (IF-NAE)  . . . . 13
       6.3.5.  Posture Validation Interface (IF-PV) . . . . . . . . . 14
   7.  Scope of Standardization . . . . . . . . . . . . . . . . . . . 14
   8.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 15
   9.  Security Considerations  . . . . . . . . . . . . . . . . . . . 15
     9.1.  Secure channel between the Client Broker and Server
           Broker . . . . . . . . . . . . . . . . . . . . . . . . . . 16
     9.2.  Authorization for Plug-in/Broker interaction . . . . . . . 16
     9.3.  Self-Integrity of the NEA Client and NEA Server  . . . . . 16
     9.4.  Protection of parameters exchanged across Interfaces . . . 16
     9.5.  Identity authentication of communicating end-points  . . . 17
   10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 17
   11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17
     11.1. Normative References . . . . . . . . . . . . . . . . . . . 17
     11.2. Informative References . . . . . . . . . . . . . . . . . . 18
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19
   Intellectual Property and Copyright Statements . . . . . . . . . . 20













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1.  Introduction

   Architectures have been implemented in the industry, e.g.  [TNC, NAP,
   NAC], to assess the software or hardware configuration of endpoint
   devices for the purposes of monitoring or enforcing compliance of
   endpoints to an organization's policy on access to the network.
   These architectures are not fully interoperable since some of the
   protocols used to implement the architecture are not standards.

   This document describes the problem these architectures are intending
   to address, defines common terminology and concepts, and identifies
   interfaces that are candidates for standardization.

   Note that this document is not intended to define a new architecture
   or framework for network endpoint assessment.  There are already
   several existing architectures for this purpose.  The network
   endpoint assessment effort aims only to identify common interfaces
   that are used in these architectures, and define standard protocols
   that can be used by the existing architectures to reduce duplication
   and achieve interoperability.


2.  Terminology

   Endpoint: An endpoint is a host connected to the network.  This broad
   definition includes (but is not limited to) desktop or laptop
   computers, servers, phones, printers.

   Posture: Posture refers to the hardware or software configuration of
   an endpoint as it pertains to an organization's security policy.
   Posture may include knowledge about the types of hardware and
   software installed and their configurations, e.g.  OS name and
   version, application patch levels, and anti-virus signature file
   version.

   NEA client: The NEA client is a set of software components on the
   endpoint that request access to the network.  The NEA client
   comprises three logical components: Posture collector, Client broker
   and Network access requestor.

   Posture collector: A Posture collector is the component of the NEA
   client that is responsible for collecting and maintaining posture
   information about the endpoint device.  There may be multiple NEA
   Posture collectors on an endpoint device each targeted at a
   particular security application from a particular vendor.

   Client broker: A Client broker is the component of the NEA client
   that aggregates posture information from multiple Posture collectors.



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   Network access requestor: The Network access requestor is the
   component of the NEA client responsible for requesting access to the
   network.

   Network enforcer: The Network enforcer is a network component that
   controls endpoint access to the upstream network.  It enforces
   network authorization decisions from the network access authority.

   NEA server: The NEA server is a server that evaluates the posture of
   an endpoint device and provides network authorization decisions.  The
   NEA server comprises three logical components: Posture validator,
   Server broker and Network access authority.

   Posture validator: A Posture validator is the logical component of
   the NEA server that assesses posture information from a Posture
   collector and determines the result of the assessment.  There may be
   multiple Posture validators each targeted at a particular security
   application from a particular vendor.

   Server broker: A Server broker is the component of the NEA server
   that aggregates posture information from multiple posture servers.

   Network access authority: The Network access authority is the
   component of the NEA server that authorizes endpoints based on a
   number of criteria including the identity of an endpoint machine
   and/or user as well as the results of posture assessment.


3.  Problem Statement

   Network endpoint assessment (NEA) architectures are systems that
   enable the network to learn the posture of an endpoint device, and
   optionally use that information in addition to machine or user
   authentication to influence a network admission decision.  Endpoint
   posture may include information about the operating system as well as
   information about security applications running on the endpoint such
   as anti-virus software, personal firewalls and host intrusion
   protection systems.

   NEA technology may be used for several purposes.  One purpose is to
   monitor or enforce compliance of endpoints to the organization's
   security policy.  Organizations often require endpoints that are
   vulnerable to attack through viruses, worms and other exploits to run
   an IT-specified OS configuration and have certain security
   applications enabled, e.g. anti-virus software, host intrusion
   protection systems, personal firewalls, and patch management
   software.  Without NEA technology, ensuring compliance of endpoints
   to corporate policy is a time-consuming and difficult task.  Not all



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   endpoints are managed by a corporation's IT organization, e.g. lab
   assets, guest machines.  Even for assets that are managed, they may
   not receive updates in a timely fashion because they are not
   permanently attached to the corporate network, e.g. laptops.  With
   NEA technology, the network is able to assess an endpoint when it
   accesses the network and while connected, providing an opportunity to
   monitor compliance of all endpoints using the network as well as
   providing the opportunity to improve endpoint compliance.  The
   decision for how to handle non-compliant endpoints is up to the
   network administrator.  Remediation instructions or warnings may be
   sent to the endpoint.  Also, network access may be restricted to
   protect the endpoint from infection and to protect the network in
   case the endpoint is already infected.

   Another use of NEA technology may be to supplement information in
   inventory databases.  In organizations that attempt to keep track of
   their assets, inventory databases tend to be incomplete and out-of-
   date.  NEA technology may be used to verify or supplement information
   stored about an organization's assets.

   As has been mentioned, many NEA architectures have been developed in
   the industry to addess the above purposes.  Certain instantiations of
   these architectures leverage the EAP framework to enable network
   admission decisions to be based on both authentication and posture
   assessment.  However, while these instantiations leverage standard
   protocols to the extent possible, e.g. 802.1X[802.1X], EAP[EAP] and
   RADIUS[RADIUS], these architectures are still not fully interoperable
   because other needed protocols have not been standardized.  The
   intent of the proposed NEA effort is to identify those interfaces
   where standarization is needed in the IETF, define requirements for
   these interfaces, and work within the IETF to define standards to
   meet these requirements.


4.  Goals

   The goals of architectures that support network assessment technology
   include some or all of the following:

   o  Support assessment of endpoints across a range of network access
      technologies, leveraging existing technology to the extent
      possible

   o  Support authorization decisions based on authentication of user or
      endpoint device, assessment of the state of the endpoint device,
      or both





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   o  Support endpoint assessment at various locations in the network
      i.e. at a L2 hop or a L3 hop, both of which may be a single hop or
      multiple hops away from the endpoint.

   o  Support endpoint assessment at possibly multiple hops on a path
      e.g. at both a L2 and a L3 hop

   o  Support network isolation of non-compliant endpoints from
      compliant endpoints for remediation or other purposes

   o  Support endpoint re-assessment when state of endpoints change, or
      rules in the NEA server change

   o  Enable integration of 3rd-party security applications so that one
      or more applications can assess the posture of an endpoint and the
      aggregate of all results can be used in network admission
      decisions.

   o  Support endpoints with a NEA client and without a client


5.  Deployment Scenarios

   Network assessment architectures have been targeted primarily at
   enterprise deployment scenarios to date.The deployment scenarios
   include:

5.1.  Wired LAN access

   In this deployment scenario, network admission control would
   typically take place at the first L2 hop from the endpoint i.e. a
   switch port.  However, there are cases where the first L2 device may
   not support network endpoint assessment for some reason, and network
   endpoint assessment may happen behind the first hop, e.g. a switch
   behind a wireless access point.

   Wired LAN access deployment scenarios may need to support single or
   multiple hosts per switch port.  Deployment scenarios with multiple
   hosts per port include IP phones + PC, or multiple PCs connected
   behind a hub.

   802.1X is an example of a standards-based network access technology
   that supports access control based on authentication for a single
   host per port in first L2 hop deployment scenarios.

5.2.  Wireless LAN Access

   In this deployment scenario, network admission control would



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   typically take place at the first L2 hop from the endpoint i.e. a
   wireless access point.  Wireless LAN access supports multiple hosts
   per wireless access point.

   802.11 is a standards-based network access technology that supports
   wireless access control based on authenticating the endpoint.

5.3.  Remote access VPN

   In this deployment scenario, network admission control is done at the
   VPN concentrator that acts as the gateway between remote users and
   access to the enterprise network.

   IPSEC VPN and SSL VPN are example of network access technologies that
   support remote access VPN deployment scenarios.

5.4.  Gateway Access

   In this deployment scenario, network admission control is enforced at
   a L3 boundary in a distributed campus network.  The L3 boundary may
   be one or more L3 hops away from the endpoint.

   This deployment scenario may be used during the transition period
   while an organization gradually upgrades network equipment to support
   network endpoint assessment.  In some cases, the technology may not
   be available immediately for first-hop L2 or L3 deployments and a
   general-purpose gateway deployment e.g. at a router behind a VPN
   concentrator, may be a reasonable first step.

   This deployment scenario may also be used between network security
   domains e.g. at the border between a less trusted/managed branch
   office and main campus, at the border between main campus or a
   visitor site and access to the Internet, at the border between
   extranet and intranet, and on access to protected servers in a data
   center.

   It follows from this deployment scenario that there may be multiple
   Network enforcers on any path that an endpoint may use in a network,
   thus resulting in it being authorized more than once.  It is also
   possible that different posture rules may be assessed at different
   network locations and a different authorization decision made.


6.  Components and Interfaces

   This section provides a general overview of NEA architectures, with a
   particular emphasis on the EAP/RADIUS instantantiation of these
   architectures, since this is the focus of the initial standards



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   effort.  (Other instantiations of the high-level architecture may be
   standardized in future.)

   Figure 1 shows the components of an NEA system and identifies
   specific interfaces.


   |-------------|                          |----------------|
   | Posture     |  <-------IF-PA------->   |   Posture      |
   | Collectors  |                          |   Validators   |
   | (1 ...N)    |                          |   (1 ...N)     |
   |-------------|                          |----------------|
         |                                          |
         |                                <------IF-PV-------->
         |                                          |
   |-------------|                          |----------------|
   |   Client    |  <-------IF-PB------->   |     Server     |
   |   Broker    |                          |     Broker     |
   |--------- ---|                          |----------------|
         |                                          |
         |                                          |
   |-------------|  <------IF-PT------->    |----------------|
   |             |                          |                |
   | Network     |    |--------|            |   Network      |
   | Access      |----|Network |------------|   Access       |
   | Requestor   |    |Enforcer| <-IF-NAE-> |   Authority    |
   |-------------|    |--------|            |----------------|

      NEA CLIENT                                  NEA SERVER
   Figure 1: NEA Components and Interfaces

6.1.  Mapping to existing architectures

   For convenience, we map the terms used in this document with that of
   three architectures developed in the industry : Trusted Network
   Connect (TNC) architecture [TNC], Microsoft's Network Access
   Protection (NAP) architecture [NAP], and Cisco's Network Admission
   Control (NAC) architecture [NAC].













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   Table 1: Terminology used in various architectures
      NEA          TNC             NAP             NAC

   Posture       Integrity       System           Posture
   Collector     Measurement     Health           Plug-in
                 Collector       Agent

   Client        TNC             NAP              Posture
   Broker        Client          Agent            Agent

   Network       Network         NAP              Posture
   Access        Access          Enforcement      Agent
   Requestor     Requestor       Client

   Network       Policy          NAP              Network
   Enforcer      Enforcement     Enforcement      Access
                 Point           Server           Device

   Posture       Integrity       System           Posture
   Validator     Measurement     Health           Validation
                 Verifier        Validator        Server

   Server        TNC             NAP              Access
   Broker        Server          Administration   Control
                                 Server           Server

   Network       Network         Network          Access
   Access        Access          Policy           Control
   Authority     Authority       Server           Server


6.2.  Components

6.2.1.  NEA Client

   The NEA client resides on an endpoint device and comprises the
   following components:

   o  Posture collector

   o  Client broker

   o  Network access requestor

6.2.1.1.  Posture Collector

   The Posture collector is software that provides posture information
   about the endpoint device to the Client broker.  There may be many



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   Posture collectors on an endpoint, one per vendor and application
   type.  Examples of Posture collectors include a host Posture
   collector that provides information about the OS and patch levels,
   anti-virus Posture collector that provides information about the
   anti-virus application, firewall Posture collector that provides
   information about the configuration of the personal firewall.

   A Posture collector is responsible for:

   o  Receiving and responding to requests for posture information on a
      per vendor and application type basis

   o  Receiving a notification of the result of the posture assessment
      and information about any actions to perform, e.g.  URL of a
      remediation server

   o  Indicating when the posture of the host has changed

6.2.1.2.  Client Broker

   The Client broker aggregates posture information from multiple
   Posture collectors.  The Client broker is responsible for:

   o  Maintaining a record of Posture collectors

   o  Multiplexing and demultiplexing posture messages between the NEA
      server and the relevant Posture collectors

   o  Determining from Posture collectors when posture has changed and
      triggering re-assessment where supported by the underlying
      transport

   o  Providing user notifications

6.2.1.3.  Network access requestor

   The Network access requestor is responsible for communicating with
   the NEA server to transport the necessary information to gain access
   to the network and for subsequent re-assessment.  There may be
   multiple Network access requestors on an endpoint representing
   different technologies for accessing the network.

6.2.2.  Network enforcer

   The Network enforcer is a network component that controls access of
   endpoints to the upstream network.  The Network enforcer may be a
   network device or a logical component on an endpoint.  The NEA
   enforcer enforces network authorization decisions from the Network



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   access authority.  There are different types of Network enforcers
   supporting different technologies for accessing the network.

6.2.3.  NEA server

   The NEA server comprises the following logical components:

   o  Network access authority

   o  Server broker

   o  Posture validator

6.2.3.1.  Network access authority

   The Network access authority is responsible for authorizing endpoints
   based on a number of criteria including the identity of an endpoint
   and/or user as well as the results of posture assessment from the
   Server broker.

6.2.3.2.  Server broker

   The Server broker aggregates posture information from potentially
   multiple Posture validators into an overall system result, and
   provides this information to the Network access authority.
   Responsibilities of the Server broker include:

   o  Maintaining a record of Posture validators

   o  Multiplexing and demultiplexing posture messages between the NEA
      client and the relevant Posture validators

   o  Aggregating posture assessment results from all Posture validators
      into an overall system result

   o  Triggering posture reassessment where supported

6.2.3.3.  Posture validator

   A Posture validator is a server that is responsible for assessing
   information from the corresponding Posture collector and determining
   the result of the assessment.  There may be multiple Posture
   validators each targeted at a particular security application from a
   particular vendor.  In some architectures, the Posture validators are
   not co-located with the NEA server.

   A Posture validator is responsible for the following:




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   o  Requesting and receiving posture information from a particular
      Posture collector

   o  Assessing the endpoint posture and providing a result to the
      Server broker

   o  Sending to the Posture collector information on remediation
      actions to be taken

   o  Indicating to the Server broker when posture reassessment may be
      needed

6.3.  Interfaces

6.3.1.  Posture Attribute interface (IF-PA)

   The IF-PA is a protocol between a Posture collector and the
   associated Posture validator for the particular vendor and
   application.  The interface is used to pass information gathered by a
   Posture collector to the Posture validator, and to pass the results
   of the assessment and information needed for remediation from the
   Posture validator to the Posture collector.

6.3.2.  Posture Broker Interface (IF-PB)

   The IF-PB is a protocol that carries aggregated posture information
   between all requested Posture collectors on an endpoint and the
   corresponding Posture validators.  This protocol also carries the
   overall system posture result from the Server broker to the Client
   broker.

6.3.3.  Posture Transport Interface (IF-PT)

   The IF-PT is the transport protocol between the Network access
   requestor and the Network access authority that carries the IF-PB
   protocol.

   In EAP instantiations of this architecture, the IF-PT interfaces
   consists of two protocols: 1) Posture Transport Tunnel (IF-PTT),
   which is an EAP tunneling method between the Network access requestor
   in the NEA client and the Network access authority in the NEA server
   that can carry posture information in addition to authentication
   information, and 2) Posture Transport Carrier (IF-PTC), a protocol
   that carries EAP, e.g.  EAP over 802.1X, EAP over RADIUS.

6.3.4.  Network Access Enforcement Interface (IF-NAE)

   The IF-NAE is the protocol between the Network enforcer and Network



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   access authority used to carry network authorization decisions
   between the Network enforcer and the Network access authority.

   In EAP Instantiations of this architecture, the IF-NAE interface is
   RADIUS.

6.3.5.  Posture Validation Interface (IF-PV)

   In some instantiations of the architecture, the Server broker and the
   Posture validators are not co-located.  The IF-PV protocol between
   the Server broker and Posture validator forwards posture information
   and returns posture validation results.


7.  Scope of Standardization

   Protocols that are candidates for standardization in the IETF include
   the following :

   o  Posture attributes interface (IF-PA): This interface can be
      defined independently of the underlying transport interfaces,
      while keeping in mind performance and other constraints imposed by
      the underlying protocols.  Many of the posture attributes will be
      vendor-specific and need only be understood by the corresponding
      Posture collector and its associated Posture validator.  However,
      there may be common attributes that would benefit from
      standardization, e.g. an attribute representing the result of
      evaluating posture information from a Posture collector.

   o  Posture broker interface (IF-PB): This interface is also largely
      independent of the underlying transport, although it should be
      defined in such a way that it can be used in posture transport
      protocols that are likely to be used, such as EAP tunneling
      methods based on TLS.

   o  Posture transport tunnel interface (IF-PTT): As described in the
      section above, in an EAP instantiation of an NEA architecture, an
      EAP tunneling method is needed to carry posture information in
      addition to authentication credentials.  Standardization of
      certain EAP methods for authentication is the proposed charter of
      the EMU WG.  The need to support posture assessment in addition to
      authentication may place additional requirements on the EAP
      methods that need to be standardized.  In particular,
      standardization of EAP tunneling methods is a high priority.

   o  Posture transport carrier interface (IF-PTC): Some EAP carrier
      methods are standards today e.g. 802.1X. However, there is no
      standard EAP transport to support gateway and other "multi-hop"



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      deployment scenarios as defined in this document.  The PANA WG
      [PANA] has proposed a specification of EAP over a UDP transport,
      although not explicitly for this use case.  Other protocols have
      been designed and used for this purpose e.g.  Network Access
      control Protocol [NACP].

   o  Network access enforcement interface (IF-NAE): Existing standards
      exist including RADIUS and Diameter.  The initial focus of the
      proposed NEA standardization effort is on RADIUS.  The Radext WG
      has the charter to standardize RADIUS extensions.  It's not clear
      that NEA would require any extensions that fall outside of the
      scope of the existing charter of that WG.

   o  Posture validator interface (IF-PV): This protocol acts as a
      carrier for posture attributes between a Server broker and a
      Posture validator that is not co-located in the NEA server.
      Depending on the choice of protocol for this purpose, this may or
      may not fall within the scope of the IETF.

   The proposed initial scope of the NEA effort is the following:

   o  IF-PTT

   o  IF-NAE

   o  IF-PB

   o  IF-PTC

   The remaining interfaces, IF-PA and IF-PV, may be addressed at a
   later date.


8.  IANA Considerations

   This document makes no request of IANA.

   Note to RFC Editor: this section may be removed on publication as an
   RFC.


9.  Security Considerations

   NEA systems include a number of functional components and interfaces,
   and thus there are a number of security aspects pertaining to the
   system as a whole which need to be highlighted.  Some of these are
   discussed in the following sections.




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9.1.  Secure channel between the Client Broker and Server Broker

   The Client broker needs to be able to communicate the posture
   information regarding the endpoint to the Server broker with
   communications integrity and confidentiality.  One possible avenue
   towards establishing this secure channel (at the peer layer of the
   Client broker and Server broker) is to establish it end-to-end
   between Network access requestor (NAR) and the Network access
   authority (NAA).  This end-to-end secure channel would prevent any
   intermediate entity, including the Network enforcer from gaining
   access to the posture information.  The exact implementation of this
   secure channel is dependent on the domain of application and network
   configuration.

9.2.  Authorization for Plug-in/Broker interaction

   There is a functional separation between the Posture collector and
   the Client broker (at the NEA client side) and also between Posture
   validator and the Server broker (at the NEA Server side).  It is
   important that a Client broker be allowed to communicate with only
   the authorized Posture collectors.  Similarly, the Server broker
   should only communicate with authorized Posture validators.  Recall
   that the Posture collector is software that provides posture
   information about the endpoint device to the Client broker.  Note
   that there may be many Posture collectors in a NEA client, one per
   vendor and application type.  Without protection, a bogus Posture
   collector (Posture validator) can open communications with the Client
   broker (Server broker), thereby opening the possibility of a Denial-
   of-Service attack (at the very least) against the Client broker and
   Server broker respectively.

9.3.  Self-Integrity of the NEA Client and NEA Server

   The trustworthiness of the posture information being reported by the
   NEA client to the NEA Server is dependent on and is only as good as
   the self-integrity of the NEA client and NEA Server respectively.  If
   malicious code or other malware are present in the NEA client
   actively modifying posture information being communicated by the NEA
   client, the NEA Server may be basing its decision-making on
   inaccurate or bogus posture information.  Thus, it is important that
   both the NEA client and the NEA Server are protected against attacks
   that illegally modify the system configurations and system components
   of these entities.

9.4.  Protection of parameters exchanged across Interfaces

   An important aspect of an NEA system is the protection of parameters
   being communicated between the various interfaces defined in the



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   architecture.  Examples of the parameters being exchanged include,
   but are not limited to, state change notifications between the Client
   broker and Posture collector, state change notifications between the
   Server broker and Posture validator, the parameters and messages
   exchanged between two peer entities (on the NEA client and NEA Server
   respectively) across IF-PA and IF-PB, and in general parameters and
   messages exchanged across interfaces IF-PT, and IF-NAE.

9.5.  Identity authentication of communicating end-points

   In order for the NEA Server to accept access requests and posture
   information being reported to by the NEA client, the NEA Server may
   need to authenticate the NEA client in some manner.  Similarly,
   within some network environments there may be the requirement that
   the NEA client also authenticate the NEA Server with whom it is
   communicating.  Although the process of evaluating an access request
   may combine together the notion of authentication and integrity state
   evaluation (through posture information), it is important from a
   security perspective and useful from a good engineering practices
   perspective to be able to separate end-point authentication
   (including both machine and user authentication) from end-point
   posture assessment.


10.  Acknowledgements

   We acknowledge the contributions from members of the NEA mailing
   list.


11.  References

11.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2865]  Rigney, C., Willens, S., Rubens, A., and W. Simpson,
              "Remote Authentication Dial In User Service (RADIUS)",
              RFC 2865, June 2000.

   [RFC3748]  Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J., and H.
              Levkowetz, "Extensible Authentication Protocol (EAP)",
              RFC 3748, June 2004.







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11.2.  Informative References

   [802.1X]   IEEE, "Local and Metropolitan Area Networks:Port-based
              Network Access Control", 2004.

   [I-D.ietf-pana-pana]
              Forsberg, D., "Protocol for Carrying Authentication for
              Network Access (PANA)", draft-ietf-pana-pana-11 (work in
              progress), March 2006.

   [I-D.thomson-nacp]
              Salowey, J., Thomson, S., Wu, F., Yarlagadda, V., and H.
              Zhou, "Network Access Control Protocol (NACP)",
              draft-thomson-nacp-02 (work in progress), March 2006.

   [NAC]      Cisco Systems, "Network Admission Control Technical
              Overview", 2005.

   [NAP]      Microsoft Corporation, "Network Access Protection Platform
              Architecture", February 2006.

   [TNC]      TCG, "TNC Architecture for Interoperability Specification
              v1.0", May 2005.




























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Authors' Addresses

   Steve Hanna
   Juniper Networks
   35 Forest Ridge Road
   Concord, MA  01742
   U.S.A.

   Phone: 781-729-9559
   Email: shanna@juniper.net


   Thomas Hardjono
   Signacert Inc
   115 SW Ash Street
   Suite 430
   Portland, OR  97204
   U.S.A

   Phone: 781-729-9559
   Email: thardjono@signacert.com


   Susan Thomson
   Cisco Systems
   499 Thornall Street, 8th floor
   Edison, NJ  08837
   U.S.A.

   Phone: 732-635-3086
   Email: sethomso@cisco.com




















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