draft-ietf-dmarc-rfc7601bis-03.txt   draft-ietf-dmarc-rfc7601bis-04.txt 
DMARC Working Group M. Kucherawy DMARC Working Group M. Kucherawy
Internet-Draft August 22, 2018 Internet-Draft November 14, 2018
Obsoletes: 7601 (if approved) Updates: 7601 (if approved)
Intended status: Standards Track Intended status: Standards Track
Expires: February 23, 2019 Expires: May 18, 2019
Message Header Field for Indicating Message Authentication Status Message Header Field for Indicating Message Authentication Status
draft-ietf-dmarc-rfc7601bis-03 draft-ietf-dmarc-rfc7601bis-04
Abstract Abstract
This document specifies a message header field called Authentication- This document specifies a message header field called Authentication-
Results for use with electronic mail messages to indicate the results Results for use with electronic mail messages to indicate the results
of message authentication efforts. Any receiver-side software, such of message authentication efforts. Any receiver-side software, such
as mail filters or Mail User Agents (MUAs), can use this header field as mail filters or Mail User Agents (MUAs), can use this header field
to relay that information in a convenient and meaningful way to users to relay that information in a convenient and meaningful way to users
or to make sorting and filtering decisions. or to make sorting and filtering decisions.
skipping to change at page 1, line 36 skipping to change at page 1, line 36
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on February 23, 2019. This Internet-Draft will expire on May 18, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 12, line 22 skipping to change at page 12, line 22
"CFWS" is defined in Section 3.2.2 of [MAIL]. "CFWS" is defined in Section 3.2.2 of [MAIL].
"domain-name" is as defined in Section 3.5 of [DKIM] where the "d=" "domain-name" is as defined in Section 3.5 of [DKIM] where the "d="
tag is defined, with "sub-domain" as modified by [RFC6531]. tag is defined, with "sub-domain" as modified by [RFC6531].
"Keyword" is defined in Section 4.1.2 of [SMTP]. It is further "Keyword" is defined in Section 4.1.2 of [SMTP]. It is further
constrained by the necessity of being registered in the IANA registry constrained by the necessity of being registered in the IANA registry
relevant to the context in which it is used. See Section 2.7, relevant to the context in which it is used. See Section 2.7,
Section 2.3, and Section 6. Section 2.3, and Section 6.
"value" is as defined in Section 5.1 of [MIME]. "value" is as defined in Section 5.1 of [MIME], with "quoted-string"
updated as specified in RFC 6532.
See Section 2.5 for a description of the authserv-id element. See Section 2.5 for a description of the authserv-id element.
If the value portion of a "pvalue" construction identifies something If the value portion of a "pvalue" construction identifies something
intended to be an email identity, then it MUST use the right hand intended to be an email identity, then it MUST use the right hand
portion of that ABNF definition. portion of that ABNF definition.
The list of commands eligible for use with the "smtp" ptype can be The list of commands eligible for use with the "smtp" ptype can be
found in Section 4.1 of [SMTP]. found in Section 4.1 of [SMTP].
skipping to change at page 33, line 18 skipping to change at page 33, line 18
If an attack becomes known against an authentication method, clearly If an attack becomes known against an authentication method, clearly
then the agent verifying that method can be fooled into thinking an then the agent verifying that method can be fooled into thinking an
inauthentic message is authentic, and thus the value of this header inauthentic message is authentic, and thus the value of this header
field can be misleading. It follows that any attack against the field can be misleading. It follows that any attack against the
authentication methods supported by this document is also a security authentication methods supported by this document is also a security
consideration here. consideration here.
7.8. Intentionally Malformed Header Fields 7.8. Intentionally Malformed Header Fields
It is possible for an attacker to add an Authentication-Results As with any other header field found in a message, it is possible for
header field that is extraordinarily large or otherwise malformed in an attacker to add an Authentication-Results header field that is
an attempt to discover or exploit weaknesses in header field parsing extraordinarily large or otherwise malformed in an attempt to
code. Implementers must thoroughly verify all such header fields discover or exploit weaknesses in header field parsing code.
received from MTAs and be robust against intentionally as well as Implementers must thoroughly verify all such header fields received
from MTAs and be robust against intentionally as well as
unintentionally malformed header fields. unintentionally malformed header fields.
7.9. Compromised Internal Hosts 7.9. Compromised Internal Hosts
An internal MUA or MTA that has been compromised could generate mail An internal MUA or MTA that has been compromised could generate mail
with a forged From header field and a forged Authentication-Results with a forged From header field and a forged Authentication-Results
header field that endorses it. Although it is clearly a larger header field that endorses it. Although it is clearly a larger
concern to have compromised internal machines than it is to prove the concern to have compromised internal machines than it is to prove the
value of this header field, this risk can be mitigated by arranging value of this header field, this risk can be mitigated by arranging
that internal MTAs will remove this header field if it claims to have that internal MTAs will remove this header field if it claims to have
 End of changes. 6 change blocks. 
11 lines changed or deleted 13 lines changed or added

This html diff was produced by rfcdiff 1.47. The latest version is available from http://tools.ietf.org/tools/rfcdiff/