MAILMAINT D. Weekly
Internet-Draft
Updates: 8058 (if approved) J. Levine
Intended status: Standards Track 22 February 2025
Expires: 26 August 2025
Adding a Wrong Recipient URL for Handling Misdirected Emails
draft-ietf-mailmaint-wrong-recipient-03
Abstract
This document describes a mechanism for an email recipient to
indicate to a sender that they are not the intended recipient.
About This Document
This note is to be removed before publishing as an RFC.
The latest revision of this draft can be found at
https://dweekly.github.io/ietf-wrong-recipient/draft-ietf-mailmaint-
wrong-recipient.html. Status information for this document may be
found at https://datatracker.ietf.org/doc/draft-ietf-mailmaint-wrong-
recipient/.
Discussion of this document takes place on the MAILMAINT Working
Group mailing list (mailto:mailmaint@ietf.org), which is archived at
https://mailarchive.ietf.org/arch/browse/mailmaint/. Subscribe at
https://www.ietf.org/mailman/listinfo/mailmaint/.
Source for this draft and an issue tracker can be found at
https://github.com/dweekly/ietf-wrong-recipient.
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
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
Weekly & Levine Expires 26 August 2025 [Page 1]
Internet-Draft Wrong Recipient February 2025
This Internet-Draft will expire on 26 August 2025.
Copyright Notice
Copyright (c) 2025 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
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Proposal . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Conventions and Definitions . . . . . . . . . . . . . . . . . 3
4. High-Level Goals . . . . . . . . . . . . . . . . . . . . . . 3
5. Out of Scope . . . . . . . . . . . . . . . . . . . . . . . . 4
6. Implementation . . . . . . . . . . . . . . . . . . . . . . . 4
6.1. Mail Senders When Sending . . . . . . . . . . . . . . . . 4
6.2. Mail Recipients . . . . . . . . . . . . . . . . . . . . . 4
6.3. Mail Senders After Wrong Sender Notification . . . . . . 4
6.4. Header syntax . . . . . . . . . . . . . . . . . . . . . . 5
7. Additional Requirements . . . . . . . . . . . . . . . . . . . 5
8. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 5
8.1. Signed HTTPS URI . . . . . . . . . . . . . . . . . . . . 5
9. Security Considerations . . . . . . . . . . . . . . . . . . . 5
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
11. Normative References . . . . . . . . . . . . . . . . . . . . 5
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
Many users with common names and/or short email addresses receive
transactional emails from service providers intended for others.
These emails can't be unsubscribed (as they are transactional) but
neither are they spam. These emails commonly are from a noreply@
email address; there is no standards-based mechanism to report a
"wrong recipient" to the sender. Doing so is in the interest of all
three involved parties: the inadvertent recipient (who does not want
the email), the sender (who wants to be able to reach their customer
and who does not want the liability of transmitting PII to a third
Weekly & Levine Expires 26 August 2025 [Page 2]
Internet-Draft Wrong Recipient February 2025
party), and the intended recipient.
This document proposes a structured mechanism for the reporting of
such misdirected email via HTTPS POST, updating the List-Unsubscribe-
Post mechanism of [RFC8058].
2. Proposal
There ought be a mechanism whereby a service can indicate it has an
endpoint to indicate a "wrong recipient" of an email. If this header
field is present in an email message, the user can select an option
to indicate that they are not the intended recipient.
Updating the one-click unsubscription [RFC8058], the mail service can
perform this action in the background as an HTTPS POST to the
provided URL without requiring the user's further attention to the
matter.
Since it's possible the user may have a separate valid account with
the sending service, it may be important that the sender be able to
tie _which_ email was sent to the wrong recipient. For this reason,
the sender may also include an opaque blob in the header field to
specify the account ID referenced in the email; this is included in
the POST.
Note that this kind of misdelivery shouldn't be possible if a service
has previously verified the user's email address for the account.
3. Conventions and Definitions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
4. High-Level Goals
Allow a recipient to stop receiving emails intended for someone else.
Allow a service to discover when they have the wrong email for a
user.
Weekly & Levine Expires 26 August 2025 [Page 3]
Internet-Draft Wrong Recipient February 2025
5. Out of Scope
This document does not propose a mechanism for automatically
discovering whether a given user is the correct recipient of an
email, though it is possible to use some of the signals in an email,
such as the intended recipient name, to infer a possible mismatch
between actual and intended recipients.
6. Implementation
6.1. Mail Senders When Sending
Mail Senders that wish to be notified when a misdelivery has occurred
SHOULD include a List-Unsubscribe: header field [RFC2369] and a List-
Unsubscribe-Post: header containing "Wrong-Recipient=One-Click".
The sender MUST encode a mapping to the underlying account identifier
in the List-Unsubscribe: URI as described in Section 3.1 of
[RFC8058].
6.2. Mail Recipients
When a mail client receives an email that includes a Wrong-Recipient
header field, an option SHOULD be exposed in the user interface that
allows a recipient to indicate that the mail was intended for another
user, if the email is reasonably assured to not be spam.
If the user selects this option, the mail client performs an HTTPS
POST to the first https URI in the List-Unsubscribe header field as
described in section 3.2 of [RFC8058].
The POST body MUST include only "Wrong-Recipient=One-Click".
6.3. Mail Senders After Wrong Sender Notification
When a misdelivery has been indicated by a POST to the HTTPS URI or
email to the given mailto: URI, the sender MUST make a reasonable
effort to cease emails to the indicated email address for that user
account.
The sender SHOULD make a best effort to attempt to discern a correct
email address for the user account, such as by using a different
known email address for that user, postal mail, text message, phone
call, app push, or presenting a notification in the user interface of
the service. How the sender should accomplish this task is not part
of this specification.
Weekly & Levine Expires 26 August 2025 [Page 4]
Internet-Draft Wrong Recipient February 2025
6.4. Header syntax
The ABNF grammar in Section 5 of [RFC8058] is augmented as follows:
postarg =/ "Wrong-Recipient=One-Click"
7. Additional Requirements
The email needs at least one valid authentication identifier, as
described in Section 4 of [RFC8058].
8. Examples
8.1. Signed HTTPS URI
Header fields in Email:
List-Unsubscribe: <https://example.com/wrongrecip/uid12345/siga29c83d>
List-Unsubscribe-Post: Wrong-Recipient=One-Click
Resulting POST request:
POST /wrongrecip/uid12345/siga29c83 HTTP/1.1
Host: example.com
Content-Length: 25
Wrong-Recipient=One-Click
9. Security Considerations
The considerations are similar to those in Section 6 of [RFC8058].
A bad actor with access to the user's email could maliciously
indicate the recipient was a Wrong Recipient with any services that
used this protocol, causing mail delivery and potentially account
access difficulties for the user.
10. IANA Considerations
This document makes no requests to IANA.
11. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/rfc/rfc2119>.
Weekly & Levine Expires 26 August 2025 [Page 5]
Internet-Draft Wrong Recipient February 2025
[RFC2369] Neufeld, G. and J. Baer, "The Use of URLs as Meta-Syntax
for Core Mail List Commands and their Transport through
Message Header Fields", RFC 2369, DOI 10.17487/RFC2369,
July 1998, <https://www.rfc-editor.org/rfc/rfc2369>.
[RFC8058] Levine, J. and T. Herkula, "Signaling One-Click
Functionality for List Email Headers", RFC 8058,
DOI 10.17487/RFC8058, January 2017,
<https://www.rfc-editor.org/rfc/rfc8058>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.
Acknowledgments
Many thanks to Oliver Deighton and Murray Kucherawy for their kind
and actionable feedback on the language and first draft of the
proposal. Thanks to Eliot Lear for helping guide the draft to the
right hands for review. A detailed review by Jim Fenton was much
appreciated and caught a number of key issues. Many thanks to the
members of IETF ART for vigorous discussion thereof and for feedback
from the MAILMAINT working group.
Authors' Addresses
David Weekly
Redwood City, CA
United States of America
Email: david@weekly.org
John Levine
United States of America
Email: standards@standcore.com
Weekly & Levine Expires 26 August 2025 [Page 6]