Sender Policy Framework (SPF) Authentication Failure Reporting Using the Abuse Reporting Format
draft-ietf-marf-spf-reporting-10
The information below is for an old version of the document that is already published as an RFC.
Document | Type |
This is an older version of an Internet-Draft that was ultimately published as RFC 6652.
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Author | Scott Kitterman | ||
Last updated | 2021-05-13 (Latest revision 2012-03-15) | ||
RFC stream | Internet Engineering Task Force (IETF) | ||
Intended RFC status | Proposed Standard | ||
Formats | |||
Reviews | |||
Additional resources | Mailing list discussion | ||
Stream | WG state | WG Document | |
Document shepherd | Murray Kucherawy | ||
Shepherd write-up | Show Last changed 2012-02-08 | ||
IESG | IESG state | Became RFC 6652 (Proposed Standard) | |
Action Holders |
(None)
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Consensus boilerplate | Unknown | ||
Telechat date | (None) | ||
Responsible AD | Pete Resnick | ||
Send notices to | (None) |
draft-ietf-marf-spf-reporting-10
MARF Working Group S. Kitterman Internet-Draft Agari Updates: 4408 (if approved) March 14, 2012 Intended status: Standards Track Expires: September 15, 2012 SPF Authentication Failure Reporting using the Abuse Report Format draft-ietf-marf-spf-reporting-10 Abstract This memo presents extensions to the Abuse Reporting Format (ARF), and Sender Policy Framework (SPF) specifications to allow for detailed reporting of message authentication failures in an on-demand fashion. This memo updates RFC4408 by providing an IANA registry for SPF modifiers. 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 http://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." This Internet-Draft will expire on September 15, 2012. 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 Provisions Relating to IETF Documents (http://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 Kitterman Expires September 15, 2012 [Page 1] Internet-Draft SPF Auth Failure Reporting March 2012 include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1. Keywords . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.2. Imported Definitions . . . . . . . . . . . . . . . . . . . 4 3. Optional Reporting Address for SPF . . . . . . . . . . . . . . 5 4. Requested Reports . . . . . . . . . . . . . . . . . . . . . . 7 4.1. Requested Reports for SPF Failures . . . . . . . . . . . . 7 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 5.1. SPF Modifier Registration . . . . . . . . . . . . . . . . 8 6. Security Considerations . . . . . . . . . . . . . . . . . . . 9 6.1. Identity Selection . . . . . . . . . . . . . . . . . . . . 9 6.2. Report Volume . . . . . . . . . . . . . . . . . . . . . . 9 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10 7.1. Normative References . . . . . . . . . . . . . . . . . . . 10 7.2. Informative References . . . . . . . . . . . . . . . . . . 10 Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 11 Appendix B. Examples . . . . . . . . . . . . . . . . . . . . . . 12 B.1. SPF DNS record for domain that sends no mail, but requests reports . . . . . . . . . . . . . . . . . . . . . 12 B.2. Minimal SPF DNS record change to add a reporting address . . . . . . . . . . . . . . . . . . . . . . . . . 12 B.3. SPF DNS record with reporting address, report percentage, and requested report type . . . . . . . . . . 12 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 13 Kitterman Expires September 15, 2012 [Page 2] Internet-Draft SPF Auth Failure Reporting March 2012 1. Introduction Abuse Reporting Format [ARF] defines a message format for sending reports of abuse in the messaging infrastructure, with an eye toward automating both the generating and consumption of those reports. Sender Policy Framework [SPF] is one mechanism for message sender authentication; it is "path-based" meaning it authenticates the route that a message took from origin to destination. The output is a verified domain name that can then be subjected to some sort of evaluation process (e.g., comparison to a known-good list, submission to a reputation service, etc.). This document extends [SPF] to add an optional reporting address and other parameters. Extension of [ARF] to add features required for the reporting of these incidents is covered in [I-D.IETF-MARF-AUTHFAILURE-REPORT] and [I-D.IETF-MARF-AS]. This document additionally creates a an IANA registry of [SPF] record modifiers to avoid modifier namespace collisions. Kitterman Expires September 15, 2012 [Page 3] Internet-Draft SPF Auth Failure Reporting March 2012 2. Definitions 2.1. 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]. 2.2. Imported Definitions The ABNF token "qp-section" is defined in [MIME]. "local-part" is defined in [MAIL]. "addr-spec" is defined in [MAIL]. Kitterman Expires September 15, 2012 [Page 4] Internet-Draft SPF Auth Failure Reporting March 2012 3. Optional Reporting Address for SPF There exist cases in which an ADministrative Management Domain (ADMD) (see [EMAIL-ARCH]) employing [SPF] for announcing sending practices may want to know when messages are received via unauthorized routing. Currently there is no such method defined in conjunction with standardized approaches such as [ARF]. Similar information can be gathered using a specially crafted [SPF] record and a special DNS server to track [SPF] record lookups. This document defines the following optional "modifier" (as defined in Section 4.6.1 of [SPF]) to SPF records, using the form defined in that specification: ra= Reporting Address (plain-text; OPTIONAL; no default). MUST be a local-part (see Section 3.4.1 of [MAIL]) specifying an e-mail address to which a report SHOULD be sent when mail claiming to be from this domain (see Section 2.4 of [SPF] for a description of how domains are identified for SPF checks) has failed the evaluation algorithm described in [SPF], in particular because a message arrived via an unauthorized route. To generate a complete address to which the report is sent, the verifier simply appends to this value an "@" followed by the SPF-compliant domain per paragraph 4.1 of [SPF]. ra= modifiers in a record that was reached by following an "include" mechanism (defined in [SPF] paragraph 5.2) MUST be ignored. ABNF: spf-report-tag = "ra=" qp-section rp= Requested Report Percentage (plain-text; OPTIONAL; default is "100"). The value is an integer from 0 to 100 inclusive that indicates what percentage of incidents of SPF failures, selected at random, are to cause reports to be generated. The report generator SHOULD NOT issue reports for more than the requested percentage of incidents. An exception to this might be some out- of-band arrangement between two parties to override it with some mutually agreed value. Report generators MAY make use of the "Incidents:" field in [ARF] to indicate that there are more reportable incidents than there are reports. ABNF: spf-rp-tag = "rp=" 1*12DIGIT "/" 1*12DIGIT Kitterman Expires September 15, 2012 [Page 5] Internet-Draft SPF Auth Failure Reporting March 2012 rr= Requested Reports (plain-text; OPTIONAL; default is "all"). The value MUST be a colon-separated list of tokens representing those conditions under which a report is desired. See Section 4.1 for a list of valid tags. ABNF: spf-rr-type = ( "all" / "e" / "f" / "s" / "n" ) spf-rr-tag = "rr=" spf-rr-type 0* ( ":" spf-rr-type ) In the absence of an "ra=" tag in the SPF record, the "rp=" and "rr=" tags MUST be ignored, and the report generator MUST NOT issue a report. Kitterman Expires September 15, 2012 [Page 6] Internet-Draft SPF Auth Failure Reporting March 2012 4. Requested Reports This memo also includes, as the "rr" tokens defined above, the means by which the sender can request reports for specific circumstances of interest. Verifiers MUST NOT generate reports for incidents that do not match a requested report, and MUST ignore requests for reports not included in this list. 4.1. Requested Reports for SPF Failures The following report requests are defined for SPF results: all All reports are requested. e Reports are requested for messages that produced an SPF result of "TempError" or "PermError". f Reports are requested for messages that produced an SPF result of "Fail". s Reports are requested for messages that produced an SPF result of "SoftFail". n Reports are requested for messages that produced an SPF result of "Neutral" or "None". Kitterman Expires September 15, 2012 [Page 7] Internet-Draft SPF Auth Failure Reporting March 2012 5. IANA Considerations As required by [IANA-CONSIDERATIONS], this section contains registry information for the new [SPF] modifiers. 5.1. SPF Modifier Registration IANA is requested to create the Sender Policy Framework Modifier Registry, to include a list of all registered SPF modifier names and their defining documents. New registrations or updates are to be published in accordance with the "Specification Required" guidelines as described in [IANA-CONSIDERATIONS]. New registrations and updates MUST contain the following information: 1. Name of the modifier being registered or updated 2. The document in which the specification of the modifier is published 3. New or updated status, which MUST be one of: current: The field is in current use deprecated: The field might be in current use but its use is discouraged historic: The field is no longer in current use An update may make a notation on an existing registration indicating that a registered field is historic or deprecated if appropriate. +------------+-----------------+---------+ | MODIFIER | REFERENCE | STATUS | +------------+-----------------+---------+ | exp | RFC4408 | current | | redirect | RFC4408 | current | | ra | (this document) | current | | rp | (this document) | current | | rr | (this document) | current | +------------+-----------------+---------+ Kitterman Expires September 15, 2012 [Page 8] Internet-Draft SPF Auth Failure Reporting March 2012 6. Security Considerations Inherited considerations: implementors are advised to consider the Security Considerations sections of [SPF], [ARF], [I-D.IETF-MARF-AS], and [I-D.IETF-MARF-AUTHFAILURE-REPORT]. In addition to the advice in the Security Considerations section of [I-D.IETF-MARF-AS], these additional considerations apply to generation of [SPF] authentication failure reports: 6.1. Identity Selection Preventing an [SPF] failure for SPF authentication failure reports is essential to mitigate the risk of data loops. If the [SMTP] return address to be used will not be the NULL return address, i.e., "MAIL FROM:<>", then the selected return address MUST be selected such that it will pass [SPF] MAIL FROM checks upon initial receipt. If the report is passed to the Mail Submission Agent (MSA) (MSA is described in [EMAIL-ARCH] using [SMTP]), the HELO/EHLO command parameter SHOULD also be selected so that it will pass [SPF] HELO checks. 6.2. Report Volume It is impossible to predict the volume of reports this facility will generate when enabled by a report receiver. An implementer ought to anticipate substantial volume, since the amount of abuse occurring at receivers cannot be known ahead of time, and may vary rapidly and unpredictably. Kitterman Expires September 15, 2012 [Page 9] Internet-Draft SPF Auth Failure Reporting March 2012 7. References 7.1. Normative References [ARF] Shafranovich, Y., Levine, J., and M. Kucherawy, "An Extensible Format for Email Feedback Reports", RFC 5965, August 2010. [I-D.IETF-MARF-AS] Falk, J. and M. Kucherawy, Ed., "Creation and Use of Email Feedback Reports: An Applicability Statement for the Abuse Reporting Format (ARF)", draft-ietf-marf-as (work in progress), February 2012. [I-D.IETF-MARF-AUTHFAILURE-REPORT] Fontana, H., "Authentication Failure Reporting using the Abuse Report Format", draft-ietf-marf-authfailure-report (work in progress), January 2012. [IANA-CONSIDERATIONS] Alvestrand, H. and T. Narten, "Guidelines for Writing an IANA Considerations Section in RFCs", RFC 5226, May 2008. [KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, March 1997. [MAIL] Resnick, P., "Internet Message Format", RFC 5322, October 2008. [MIME] Freed, N. and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies", RFC 2045, November 1996. [SMTP] Klensin, J., "Simple Mail Transfer Protocol", RFC 5321, October 2008. [SPF] Wong, M. and W. Schlitt, "Sender Policy Framework (SPF) for Authorizing Use of Domains in E-Mail, Version 1", RFC 4408, April 2006. 7.2. Informative References [EMAIL-ARCH] Crocker, D., "Internet Mail Architecture", RFC 5598, October 2008. Kitterman Expires September 15, 2012 [Page 10] Internet-Draft SPF Auth Failure Reporting March 2012 Appendix A. Acknowledgements The author wishes to acknowledge the following for their review and constructive criticism of this proposal: Murray Kucherawy, Tim Draegen, Julian Mehnle, and John Levine. Kitterman Expires September 15, 2012 [Page 11] Internet-Draft SPF Auth Failure Reporting March 2012 Appendix B. Examples B.1. SPF DNS record for domain that sends no mail, but requests reports v=spf1 ra=postmaster -all B.2. Minimal SPF DNS record change to add a reporting address v=spf1 mx:example.org ra=postmaster -all B.3. SPF DNS record with reporting address, report percentage, and requested report type v=spf1 mx:example.org -all ra=postmaster rp=10 rr=e Kitterman Expires September 15, 2012 [Page 12] Internet-Draft SPF Auth Failure Reporting March 2012 Author's Address Scott Kitterman Agari 3611 Scheel Dr Ellicott City, MD 21042 US Phone: +1 301 325 5475 Email: skitterman@agari.com Kitterman Expires September 15, 2012 [Page 13]