Network Working Group                                      L. Velvindron
Internet-Draft                                             cyberstorm.mu
Intended status: Standards Track                              S. Farrell
Expires: March 25, 2019                           Trinity College Dublin
                                                      September 21, 2018


 Use of Transport Layer Security (TLS) for Email Submission and Access
                   draft-lvelvindron-tls-for-email-01

Abstract

   This specification updates current recommendation for the use of
   Transport Layer Security (TLS) protocol to provide confidentiality of
   email between a Mail User Agent (MUA) and a Mail Submission Server or
   Mail Access Server.  This document updates RFC8314.

Status of This Memo

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

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   This Internet-Draft will expire on March 25, 2019.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Updates to RFC8314  . . . . . . . . . . . . . . . . . . . . .   2
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   5.  Normative References  . . . . . . . . . . . . . . . . . . . .   4
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   4

.  Introduction

   [RFC8314] defines the minimum recommended for TLS as version 1.1.
   Due to the deprecation of TLS 1.1 in draft-ietf-tls-oldversions-
   deprecate, this recommendation is no longer valid.  Therefore this
   document updates [RFC8314] so that the minimum version for TLS is TLS
   1.2.

.  Updates to RFC8314

   In the Table of contents section, the text should be revised from:
   "4.1.  Deprecation of Services Using Cleartext and TLS Versions Less
   Than 1.1" to: "4.1.  Deprecation of Services Using Cleartext and TLS
   Versions Less Than 1.2"

   In section 4, the text should be revised from: "As soon as
   practicable, MSPs currently supporting Secure Sockets Layer (SSL)
   2.x, SSL 3.0, or TLS 1.0 SHOULD transition their users to TLS 1.1 or
   later and discontinue support for those earlier versions of SSL and
   TLS." to: "As soon as practicable, MSPs currently supporting Secure
   Sockets Layer (SSL) 2.x, SSL 3.0, or TLS 1.0 SHOULD transition their
   users to TLS 1.2 or later and discontinue support for those earlier
   versions of SSL and TLS."

   In Section 4.1, the text should be revised from: "It is RECOMMENDED
   that new users be required to use TLS version 1.1 or greater from the
   start.  However, an MSP may find it necessary to make exceptions to
   accommodate some legacy systems that support only earlier versions of
   TLS or only cleartext." to: "It is RECOMMENDED that new users be
   required to use TLS version 1.2 or greater from the start.  However,
   an MSP may find it necessary to make exceptions to accommodate some
   legacy systems that support only earlier versions of TLS or only
   cleartext."

   In section 5, the text should be revised from: " MUAs SHOULD provide
   a prominent indication of the level of confidentiality associated
   with an account configuration that is appropriate for the user
   interface (for example, a "lock" icon or changed background color for
   a visual interface, or some sort of audible indication for an audio



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   user interface), at appropriate times and/or locations, in order to
   inform the user of the confidentiality of the communications
   associated with that account.  For example, this might be done
   whenever (a) the user is prompted for authentication credentials, (b)
   the user is composing mail that will be sent to a particular
   submission server, (c) a list of accounts is displayed (particularly
   if the user can select from that list to read mail), or (d) the user
   is asking to view or update any configuration data that will be
   stored on a remote server.  If, however, an MUA provides such an
   indication, it MUST NOT indicate confidentiality for any connection
   that does not at least use TLS 1.1 with certificate verification and
   also meet the minimum confidentiality requirements associated with
   that account.  " to: " MUAs SHOULD provide a prominent indication of
   the level of confidentiality associated with an account configuration
   that is appropriate for the user interface (for example, a "lock"
   icon or changed background color for a visual interface, or some sort
   of audible indication for an audio user interface), at appropriate
   times and/or locations, in order to inform the user of the
   confidentiality of the communications associated with that account.
   For example, this might be done whenever (a) the user is prompted for
   authentication credentials, (b) the user is composing mail that will
   be sent to a particular submission server, (c) a list of accounts is
   displayed (particularly if the user can select from that list to read
   mail), or (d) the user is asking to view or update any configuration
   data that will be stored on a remote server.  If, however, an MUA
   provides such an indication, it MUST NOT indicate confidentiality for
   any connection that does not at least use TLS 1.2 with certificate
   verification and also meet the minimum confidentiality requirements
   associated with that account.  "

   In Section 5 the text should be revised from: " MUAs MUST implement
   TLS 1.2 [RFC5246] or later.  Earlier TLS and SSL versions MAY also be
   supported, so long as the MUA requires at least TLS 1.1 [RFC4346]
   when accessing accounts that are configured to impose minimum
   confidentiality requirements.  " to: " MUAs MUST implement TLS 1.2
   [RFC5246] or later.  Earlier TLS and SSL versions MAY also be
   supported, so long as the MUA requires at least TLS 1.2 [RFC5246]
   when accessing accounts that are configured to impose minimum
   confidentiality requirements.  "

   In Section 5.2 second paragraph, the text should be revised from: "
   The default minimum expected level of confidentiality for all new
   accounts MUST require successful validation of the server's
   certificate and SHOULD require negotiation of TLS version 1.2 or
   greater.  (Future revisions to this specification may raise these
   requirements or impose additional requirements to address newly
   discovered weaknesses in protocols or cryptographic algorithms.  "
   to: " The default minimum expected level of confidentiality for all



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   new accounts MUST require successful validation of the server's
   certificate and SHOULD require negotiation of TLS version 1.2 or
   greater.  (Future revisions to this specification may raise these
   requirements or impose additional requirements to address newly
   discovered weaknesses in protocols or cryptographic algorithms.  "

.  IANA Considerations

   None of the proposed measures have an impact on IANA.

.  Security Considerations

   The purpose of this document is to document updated recommendations
   for using TLS with Email services.

.  Normative References

   [RFC8314]  Moore, K. and C. Newman, "Cleartext Considered Obsolete:
              Use of Transport Layer Security (TLS) for Email Submission
              and Access", RFC 8314, DOI 10.17487/RFC8314, January 2018,
              <https://www.rfc-editor.org/info/rfc8314>.

Authors' Addresses

   Loganaden Velvindron
   cyberstorm.mu
   88 Avenue De Plevitz Roches Brunes
   Rose Hill  71259
   Mauritius

   Phone: +230 59762817
   Email: loganaden@gmail.com


   Stephen Farrell
   Trinity College Dublin
   Dublin  2
   Ireland

   Phone: +353-1-896-2354
   Email: stephen.farrell@cs.tcd.ie










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