PT-EAP: Posture Transport (PT) Protocol for Extensible Authentication Protocol (EAP) Tunnel Methods
RFC 7171

Internet Engineering Task Force (IETF)                     N. Cam-Winget
Request for Comments: 7171                                 Cisco Systems
Category: Standards Track                                    P. Sangster
ISSN: 2070-1721                                     Symantec Corporation
                                                                May 2014

                PT-EAP: Posture Transport (PT) Protocol
      for Extensible Authentication Protocol (EAP) Tunnel Methods

Abstract

   This document specifies PT-EAP, a Posture Transport (PT) protocol
   based on the Extensible Authentication Protocol (EAP) and designed to
   be used only inside an EAP tunnel method protected by Transport Layer
   Security (TLS).  The document also describes the intended
   applicability of PT-EAP.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc7171.

Copyright Notice

   Copyright (c) 2014 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   described in the Simplified BSD License.

Cam-Winget & Sangster        Standards Track                    [Page 1]
RFC 7171                       NEA PT-EAP                       May 2014

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Prerequisites . . . . . . . . . . . . . . . . . . . . . .   3
     1.2.  Message Diagram Conventions . . . . . . . . . . . . . . .   3
     1.3.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
     1.4.  Conventions Used in This Document . . . . . . . . . . . .   4
     1.5.  Compatibility with Other Specifications . . . . . . . . .   4
   2.  Use of PT-EAP . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Definition of PT-EAP  . . . . . . . . . . . . . . . . . . . .   4
     3.1.  Protocol Overview . . . . . . . . . . . . . . . . . . . .   5
     3.2.  Version Negotiation . . . . . . . . . . . . . . . . . . .   6
     3.3.  PT-EAP Message Format . . . . . . . . . . . . . . . . . .   6
     3.4.  Preventing MITM Attacks with Channel Bindings . . . . . .   8
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
     4.1.  Trust Relationships . . . . . . . . . . . . . . . . . . .   9
       4.1.1.  Posture Transport Client  . . . . . . . . . . . . . .   9
       4.1.2.  Posture Transport Server  . . . . . . . . . . . . . .  10
     4.2.  Threats and Countermeasures . . . . . . . . . . . . . . .  10
       4.2.1.  Message Confidentiality . . . . . . . . . . . . . . .  11
       4.2.2.  Message Fabrication . . . . . . . . . . . . . . . . .  11
       4.2.3.  Message Modification  . . . . . . . . . . . . . . . .  12
       4.2.4.  Denial of Service . . . . . . . . . . . . . . . . . .  12
       4.2.5.  NEA Asokan Attacks  . . . . . . . . . . . . . . . . .  13
     4.3.  Candidate EAP Tunnel Method Protections . . . . . . . . .  13
     4.4.  Security Claims for PT-EAP as per RFC 3748  . . . . . . .  14
   5.  Requirements for EAP Tunnel Methods . . . . . . . . . . . . .  14
   6.  Privacy Considerations  . . . . . . . . . . . . . . . . . . .  16
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  16
     7.1.  Registry for PT-EAP Versions  . . . . . . . . . . . . . .  17
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  17
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  18
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  18
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  18

1.  Introduction

   This document specifies PT-EAP, a Posture Transport (PT) protocol
   protected by a TLS-protected EAP tunnel method.  The PT protocol in
   the Network Endpoint Assessment (NEA) architecture is responsible for