One document matched: draft-zorn-emu-eap-pwc-00.txt

Network Working Group                                            G. Zorn
Internet-Draft                                               Network Zen
Intended status: Standards Track                           March 7, 2011
Expires: September 8, 2011


      A Method for Changing Cleartext Passwords in the Extensible
                        Authentication Protocol
                       draft-zorn-emu-eap-pwc-00

Abstract

   The Extensible Authentication Protocol (EAP) provides support for
   multiple authentication methods.  One such method is Generic Token
   Card (EAP-GTC) which, despite its name, is commonly used to support
   authentication using cleartext passwords in tunneled EAP methods.
   EAP-GTC does not provide the ability to change a password (for
   example, an expired password), however.  This document defines the
   PassWord Change EAP method (EAP-PWC) in order to fill that void in
   functionality.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.  This document may not be modified,
   and derivative works of it may not be created, except to format it
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   This Internet-Draft will expire on September 8, 2011.

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   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents



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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . . . 3
   3.  EAP-PWC . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
   4.  Security Considerations . . . . . . . . . . . . . . . . . . . . 4
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 5
     6.1.  Normative References  . . . . . . . . . . . . . . . . . . . 5
     6.2.  Informative References  . . . . . . . . . . . . . . . . . . 5

































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1.  Introduction

   The Generic Token Card EAP method (EAP-GTC) [RFC3748] is commonly
   used to support authentication using cleartext passwords in tunneled
   EAP methods.  However, EAP-GTC does not provide the ability to change
   a password (for example, one which is about to expire).  This
   document defines the PassWord Change EAP method (EAP-PWC) in order to
   fill that void in EAP functionality.

2.  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 [RFC2119].

3.  EAP-PWC

   Description

      If the EAP authenticator determines that the password should be
      changed as a result of the evaluation of the EAP/Identity
      response, it SHOULD send an EAP-PWC/Request to the peer.  The
      Request contains a pair of displayable messages separated by the
      NUL character (0x00) and the Response contains the old and new
      passwords, also separated by a single NUL character.  A Response
      MUST be sent in reply to the Request.  The Response MUST be of
      Type <TBD> (PWC), Nak (Type 3), or Expanded Nak (Type 254)
      [RFC3748].  The Nak Response indicates the peer's desired
      authentication Type(s).  The EAP-PWC method MUST NOT be used to
      provide support for cleartext password change in the absence of a
      protected tunnel with server authentication (e.g., TEAM
      [I-D.zorn-emu-team]).

   Type

      <TBD>

   Type-Data

      The Type-Data field in the Request contains a displayable message
      concatenated with a single NUL character concatenated with a
      displayable message.  Each of the messages MUST be individually
      processed according to the rules of the [RFC4013] profile of
      [RFC3454] before the concatenation is performed.  The messages
      SHALL be considered to be "stored strings" per [RFC3454], and
      unassigned code points are therefore prohibited.  The output SHALL
      be the binary representation of the processed UTF-8 character
      string.  Prohibited output and unassigned codepoints encountered



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      in SASLprep pre-processing SHALL cause a failure of pre-
      processing, and the output SHALL NOT be used with EAP-PWC.

      The Type-Data field in the Response contains the old password
      concatenated with a single NUL character concatenated with the new
      password.  Each of the strings MUST be individually processed
      according to the rules of the [RFC4013] profile of [RFC3454]
      before the concatenation is performed.  The passwords SHALL be
      considered to be "stored strings" per [RFC3454], and unassigned
      code points are therefore prohibited.  The output SHALL be the
      binary representation of the processed UTF-8 character string.
      Prohibited output and unassigned codepoints encountered in
      SASLprep pre-processing SHALL cause a failure of pre-processing,
      and the output SHALL NOT be used with EAP-PWC.

   Security Claims

      Auth. mechanism:          Cleartext password
      Ciphersuite negotiation:  No
      Mutual authentication:    No
      Integrity protection:     No
      Replay protection:        No
      Confidentiality:          No
      Key derivation:           No
      Key strength:             N/A
      Dictionary attack prot.:  No
      Fast reconnect:           No
      Crypto binding:           N/A
      Session independence:     N/A
      Fragmentation:            No
      Channel binding:          No

4.  Security Considerations

   The EAP-PWC method MUST NOT be used in the absence of a
   cryptographically protected tunnel with server authentication.

5.  IANA Considerations

   This memo requires IANA to allocate a new EAP method type for EAP-
   PWC.  The placeholder indicated by <TBD> in Section 3 above shall be
   replaced by the new EAP method type upon assignment by IANA.

6.  References







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6.1.  Normative References

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

   [RFC3454]            Hoffman, P. and M. Blanchet, "Preparation of
                        Internationalized Strings ("stringprep")",
                        RFC 3454, December 2002.

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

   [RFC4013]            Zeilenga, K., "SASLprep: Stringprep Profile for
                        User Names and Passwords", RFC 4013,
                        February 2005.

6.2.  Informative References

   [I-D.zorn-emu-team]  Zorn, G., Wu, W., and D. Harkins, "The Tunneled
                        Extensible Authentication Protocol Method
                        (TEAM)", draft-zorn-emu-team-01 (work in
                        progress), October 2010.

Author's Address

   Glen Zorn
   Network Zen
   227/358 Thanon Sanphawut
   Bang Na, Bangkok  10260
   Thailand

   Phone: +66 (0) 87-040-4617
   EMail: gwz@net-zen.net
















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