A Reputation Response Set for Email Identifiers
draft-ietf-repute-email-identifiers-05

The information below is for an old version of the document
Document Type Active Internet-Draft (repute WG)
Authors Nathaniel Borenstein  , Murray Kucherawy 
Last updated 2012-11-13
Replaces draft-kucherawy-reputation-vocab-identity
Stream Internet Engineering Task Force (IETF)
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Send notices to repute-chairs@tools.ietf.org, draft-ietf-repute-email-identifiers@tools.ietf.org
REPUTE Working Group                                       N. Borenstein
Internet-Draft                                                  Mimecast
Intended status: Standards Track                            M. Kucherawy
Expires: May 17, 2013                                  November 13, 2012

            A Reputation Response Set for Email Identifiers
                 draft-ietf-repute-email-identifiers-05

Abstract

   This document defines a response set for describing assertions a
   reputation service provider can make about email identifers, for use
   in generating reputons.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on May 17, 2013.

Copyright Notice

   Copyright (c) 2012 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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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Terminology and Definitions . . . . . . . . . . . . . . . . . . 3
     2.1.  Key Words . . . . . . . . . . . . . . . . . . . . . . . . . 3
     2.2.  Email Definitions . . . . . . . . . . . . . . . . . . . . . 3
     2.3.  Other Definitions . . . . . . . . . . . . . . . . . . . . . 3
   3.  Discussion  . . . . . . . . . . . . . . . . . . . . . . . . . . 3
     3.1.  Assertions  . . . . . . . . . . . . . . . . . . . . . . . . 3
     3.2.  Response Set Extensions . . . . . . . . . . . . . . . . . . 4
     3.3.  Query Extensions  . . . . . . . . . . . . . . . . . . . . . 5
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
     4.1.  Registration of 'email-id' Reputation Application . . . . . 5
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 6
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 6
     6.1.  Normative References  . . . . . . . . . . . . . . . . . . . 6
     6.2.  Informative References  . . . . . . . . . . . . . . . . . . 7
   Appendix A.  Acknowledgments  . . . . . . . . . . . . . . . . . . . 7
   Appendix B.  Public Discussion  . . . . . . . . . . . . . . . . . . 7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 7

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1.  Introduction

   This document specifies a response set for describing reputation of
   an email identifier.  A "response set" in this context is defined in
   [I-D.REPUTE-MODEL] and is used to describe assertions a reputation
   service provider can make about email identifiers as well as meta-
   data that can be included in such a reply beyond the base set
   specified there.

   An atomic reputation response is called a "reputon", also defined in
   that document.

2.  Terminology and Definitions

   This section defines terms used in the rest of the document.

2.1.  Key Words

   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 [KEYWORDS].

2.2.  Email Definitions

   Commonly used definitions describing entities in the email
   architecture are defined and discussed in [EMAIL-ARCH].

2.3.  Other Definitions

   Other terms of importance in this document are defined in
   [I-D.REPUTE-MODEL], the base document for the reputation services
   work.

3.  Discussion

   The expression of reputation about an email identifier requires
   extensions of the base set defined in [I-D.REPUTE-MODEL].  This
   document defines and registers some common assertions about an entity
   found in a piece of [MAIL].

3.1.  Assertions

   The "email-id" reputation application recognizes the following
   assertions:

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   FRAUD:  The subject identifier is associated with sending or handling
      of fraudulent email, such as "phishing" (some good discussion on
      this topic can be found in [IODEF-PHISHING])

   INVALID-RECIPIENTS:  The subject identifier is associated with
      delivery attempts to nonexistent recipients

   MALWARE:  The subject identifier is associated with the sending or
      handling of malware via email

   SPAM:  The subject identifier is associated with sending or handling
      of unwanted bulk email

   For all assertions, the RATING scale is linear: A value of 0.0 means
   there is no data to support the assertion, a value of 1.0 means all
   accumulated data support the assertion, and the intervening values
   have a linear relationship (i.e., a score of "x" is twice as strong
   of an assertion as a value of "x/2").

3.2.  Response Set Extensions

   The "email-id" reputation application recognizes the following
   OPTIONAL extensions to the basic response set defined in
   [I-D.REPUTE-MODEL]:

   IDENTITY:  A token indicating the source of the identifier; that is,
      where the subject identifier was found in the message.  This MUST
      be one of:

      DKIM:  The signing domain, i.e. the value of the "d=" tag, found
         on a valid [DKIM] signature in the message

      IPV4:  The IPv4 address of the client

      IPV6:  The IPv6 address of the client

      RFC5321.HELO:  The RFC5321.Helo value used by the (see [SMTP])
         client

      RFC5321.MAILFROM:  The RFC5321.MailFrom value of the envelope of a
         message of the message (see [SMTP])

      RFC5322.FROM:  The RFC5322.From field of the message (see [MAIL])

      SPF:  The domain name portion of the identifier (RFC5321.MailFrom
         or RFC5321.Helo) verified by [SPF])

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   SOURCES:  A token relating a count of the number of sources of data
      that contributed to the reported reputation.  This is in contrast
      to the SAMPLE-SIZE parameter, which indicates the total number of
      reports across all reporting sources.

   A reply that does not contain the IDENTITY or SOURCES extensions is
   making a non-specific statement about how the reputation returned was
   developed.  A client can use or ignore such a reply at its
   discretion.

3.3.  Query Extensions

   A query within this application can include the OPTIONAL query
   parameter "identity" to indicate which specific identity is of
   interest to the query.  Legal values are the same as those listed in
   Section 3.2.

4.  IANA Considerations

   This memo presents one action for IANA, namely the registration of
   the reputation application "email-id".

4.1.  Registration of 'email-id' Reputation Application

   This section registers the "email-id" reputation application, as per
   the IANA Considerations section of [I-D.REPUTE-MODEL].  The
   registration parameters are as folows:

   o  Application name: email-id

   o  Short description: Evaluates DNS domain names found in email
      identifiers

   o  Defining document: [this document]

   o  Status: current

   o  Subject: A string appropriate to the identifier of interest (see
      Section 3.2 of this document)

   o  Application-specific query parameters:

      identity:  (current) as defined in Section 3.3 of this document

   o  Application-specific assertions:

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      fraud:  (current) as defined in Section 3.1 of this document

      invalid-recipients:  (current) as defined in Section 3.1 of this
         document

      malware:  (current) as defined in Section 3.1 of this document

      spam:  (current) as defined in Section 3.1 of this document

   o  Application-specific response set extensions:

      identity:  (current) as defined in Section 3.2 of this document

5.  Security Considerations

   This document is primarily an IANA action and doesn't describe any
   protocols or protocol elements that might introduce new security
   concerns.

   Security considerations relevant to email and email authentication
   can be found in most of the documents listed in the References
   sections below.  Information specific to use of reputation services
   can be found in [I-D.REPUTE-CONSIDERATIONS].

6.  References

6.1.  Normative References

   [DKIM]     Crocker, D., Ed., Hansen, T., Ed., and M. Kucherawy, Ed.,
              "DomainKeys Identified Mail (DKIM) Signatures", RFC 6376,
              September 2011.

   [EMAIL-ARCH]
              Crocker, D., "Internet Mail Architecture", RFC 5598,
              July 2009.

   [I-D.REPUTE-MODEL]
              Borenstein, N. and M. Kucherawy, "A Model for Reputation
              Interchange", draft-ietf-repute-model (work in progress),
              November 2012.

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

   [SPF]      Wong, M. and W. Schlitt, "Sender Policy Framework (SPF)

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              for Authorizing Use of Domains in E-Mail, Version 1",
              RFC 4408, April 2006.

6.2.  Informative References

   [I-D.REPUTE-CONSIDERATIONS]
              Kucherawy, M., "Operational Considerations Regarding
              Reputation Services", draft-ietf-repute-considerations
              (work in progress), November 2012.

   [IODEF-PHISHING]
              Cain, P. and D. Jevans, "Extensions to the IODEF-Document
              Class for Reporting Phishing", RFC 5901, July 2010.

   [MAIL]     Resnick, P., Ed., "Internet Message Format", RFC 5322,
              October 2008.

   [SMTP]     Klensin, J., "Simple Mail Transfer Protocol", RFC 5321,
              October 2008.

Appendix A.  Acknowledgments

   The authors wish to acknowledge the contributions of the following to
   this specification: Scott Kitterman, John Levine, S. Moonesamy, Doug
   Otis, and David F. Skoll.

Appendix B.  Public Discussion

   Public discussion of this suite of memos takes place on the
   domainrep@ietf.org mailing list.  See
   https://www.ietf.org/mailman/listinfo/domainrep.

Authors' Addresses

   Nathaniel Borenstein
   Mimecast
   203 Crescent St., Suite 303
   Waltham, MA  02453
   USA

   Phone: +1 781 996 5340
   Email: nsb@guppylake.com

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   Murray S. Kucherawy
   2063 42nd Avenue
   San Francisco, CA  94116
   USA

   Email: superuser@gmail.com

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