Network Working Group N. Borenstein
Internet-Draft Mimecast
Intended status: Informational M. Kucherawy
Expires: December 3, 2011 Cloudmark
June 1, 2011
A Reputation Vocabulary for Email Properties
draft-kucherawy-reputation-vocab-email-00
Abstract
This document defines a vocabulary for describing email identities
(typically authors or signers) with the application/reputon media
type.
Status of this Memo
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This Internet-Draft will expire on December 3, 2011.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Document Series . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Terminology and Definitions . . . . . . . . . . . . . . . . . . 3
3.1. Keywords . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.2. Email Definitions . . . . . . . . . . . . . . . . . . . . . 4
3.3. Other Definitions . . . . . . . . . . . . . . . . . . . . . 4
4. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4.1. Assertions . . . . . . . . . . . . . . . . . . . . . . . . 4
4.2. Vocabulary Extensions . . . . . . . . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
5.1. Registration of 'email-content' Reputation Application . . 5
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 5
6.1. General . . . . . . . . . . . . . . . . . . . . . . . . . . 6
7. Informative References . . . . . . . . . . . . . . . . . . . . 6
Appendix A. Public Discussion . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
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1. Introduction
This memo defines a "vocabulary" for describing reputation of a
property of an email message that is not an identity. A "vocabulary"
in this context is defined in [RFCxxxx] and is used to describe
assertions a reputation service provider can make about properties of
an email message as well as meta-data that can be included in such a
reply beyond the base set specified there.
A separate document in this series declares a vocabulary for use in
relating reputation information about an identity found in an email
message.
2. Document Series
This memo represents the media type registration, part of a series of
documents that define the overall service and introduce the initial
exemplary applications. The series is as follows:
1. RFCxxxx: A Model for Reputation Interchange
2. RFCxxxx+1: A Media Type for Reputation Information
3. RFCxxxx+2: Using UDP for Reputation Interchange
4. RFCxxxx+3: Using the DNS for Reputation Interchange
5. RFCxxxx+4: Using HTTP/XML for Reputation Interchange
6. RFCxxxx+5: A Reputation Vocabulary for Email Identity Reputation
7. RFCxxxx+6: A Reputation Vocabulary for Email Property Reputation
(this memo)
3. Terminology and Definitions
This section defines terms used in the rest of the document.
3.1. Keywords
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].
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3.2. Email Definitions
Commonly used definitions describing entities in the email
architecture are defined and discussed in [EMAIL-ARCH].
3.3. Other Definitions
Other terms of importance in this memo are defined in RFCxxxx, the
base memo in this document series.
4. Discussion
The expression of reputation about an email property requires
extensions of the base set defined in [RFCxxxx]. This memo defines
and registers some common assertions about an entity found in a piece
of [MAIL].
Unless otherwise noted, the property extracted from the message MUST
be preserved precisely, with no characters omitted even if they are
considered syntax errors within context.
4.1. Assertions
The "email" reputation application recognizes the following
assertions:
CONTAINS-MALWARE: The subject property is associated with messages
that contain malware
IS-PHISH: The subject property is associated with fraudulent email
with a goal of identity theft
IS-SPAM: The subject property is associated with unwanted bulk email
4.2. Vocabulary Extensions
The "email-content" reputation application recognizes the following
extensions to the vocabulary defined in [RFCxxxx]:
SOURCE: A token indicating the source of the property; that is,
where the subject property was found in the message. This MUST be
one of:
RFC5321.MAILFROM: The RFC5321.MailFrom value of the envelope of a
message of the message (see [SMTP])
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RFC5322.FROM: The RFC5322.From field of the message (see [MAIL]).
Any folding whitespace MUST be rewritten to a single linear
space character (ASCII 32).
RFC5322.MESSAGE-ID: The RFC5322.Message-Id field of the message
(see [MAIL])
RFC5322.SUBJECT: The RFC5322.Subject field of the message (see
[MAIL]). Any folding whitespace MUST be rewritten to a single
linear space character (ASCII 32).
UNSPECIFIED: Any arbitrary string from anywhere in the message.
URI: A complete URI found in the message, such as the content of
a "src" tag in an "img" element, or an "href" tag in an "a"
element. (See [URI] and [HTML]).
URI-HOST: The "host" portion of a URI found in the message. Note
that this can be a DNS domain name or an IP address, each in
any of various encodings. (See [URI] and [HTML]).
5. IANA Considerations
This memo presents one action for IANA, namely the registraton of the
reputation application "email-content".
5.1. Registration of 'email-content' Reputation Application
This section registers the "email-content" reputation application, as
defined in [RFCxxxx+1]. The registration parameters are as folows:
o Application name: email-content
o Short description: Evaluates any of various properties of an email
message that are not identities
o Defining document: [this memo]
o Status: current
6. Security Considerations
This memo describes security considerations introduced by the media
type defined here.
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6.1. General
This memo is part of a series introducing a reputation query and
response system (see Section 2). The Security Considerations
sections of the other memos should also be consulted.
7. Informative References
[EMAIL-ARCH]
Crocker, D., "Internet Mail Architecture", RFC 5598,
July 2009.
[HTML] Raggett, D., Le Hors, A., and I. Jacobs, "HTML 4.01
Specification", December 1999,
<http://www.w3.org/TR/html401/>.
[KEYWORDS]
Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[MAIL] Resnick, P., Ed., "Internet Message Format", RFC 5322,
October 2008.
[SMTP] Klensin, J., "Simple Mail Transfer Protocol", RFC 5321,
October 2008.
[URI] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", RFC 3986,
January 2005.
Appendix A. 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.
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Authors' Addresses
Nathaniel Borenstein
Mimecast
203 Crescent St., Suite 303
Waltham, MA 02453
USA
Phone: +1 781 996 5340
Email: nsb@guppylake.com
Murray S. Kucherawy
Cloudmark
128 King St., 2nd Floor
San Francisco, CA 94107
USA
Phone: +1 415 946 3800
Email: msk@cloudmark.com
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