Updates to Using the NETCONF Protocol over Transport Layer Security (TLS) with Mutual X.509 Authentication
draft-ietf-netconf-over-tls13-04

Network Configuration                                          S. Turner
Internet-Draft                                                     sn3rd
Updates: 7589 (if approved)                                   R. Housley
Intended status: Standards Track                          Vigil Security
Expires: 21 July 2024                                    18 January 2024

  Updates to Using the NETCONF Protocol over Transport Layer Security
                 (TLS) with Mutual X.509 Authentication
                    draft-ietf-netconf-over-tls13-04

Abstract

   RFC 7589 defines how to protect NETCONF messages with TLS 1.2.  This
   document updates RFC 7589 to update support requirements for TLS 1.2
   and add TLS 1.3 support requirements, including restrictions on the
   use of TLS 1.3's early data.

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://netconf-
   wg.github.io/netconf-over-tls13/draft-ietf-netconf-over-tls13.html.
   Status information for this document may be found at
   https://datatracker.ietf.org/doc/draft-ietf-netconf-over-tls13/.

   Discussion of this document takes place on the Network Configuration
   Working Group mailing list (mailto:netconf@ietf.org), which is
   archived at https://mailarchive.ietf.org/arch/browse/netconf/.
   Subscribe at https://www.ietf.org/mailman/listinfo/netconf/.

   Source for this draft and an issue tracker can be found at
   https://github.com/netconf-wg/netconf-over-tls13.

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/.

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   Internet-Drafts are draft documents valid for a maximum of six months
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   This Internet-Draft will expire on 21 July 2024.

Copyright Notice

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   document authors.  All rights reserved.

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   Please review these documents carefully, as they describe your rights
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   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions and Definitions . . . . . . . . . . . . . . . . .   3
   3.  Early Data  . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Cipher Suites . . . . . . . . . . . . . . . . . . . . . . . .   3
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   7.  Normative References  . . . . . . . . . . . . . . . . . . . .   5
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .   6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   [RFC7589] defines how to protect NETCONF messages [RFC6241] with TLS
   1.2 [RFC5246].  This document updates [RFC7589] to update support
   requirements for TLS 1.2 [RFC5246] and to add TLS 1.3
   [I-D.ietf-tls-rfc8446bis] support requirements, including
   restrictions on the use of TLS 1.3's early data which is also known
   as 0-RTT data.  It also updates the "netconf-tls" IANA Registered
   Port Number entry to refer to this document.  All other provisions
   set forth in [RFC7589] are unchanged, including connection
   initiation, message framing, connection closure, certificate
   validation, server identity, and client identity.

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      |  NOTE: Implementations that support TLS 1.3
      |  [I-D.ietf-tls-rfc8446bis] should refer to TLS 1.3
      |  [I-D.ietf-tls-rfc8446bis] in Sections 4 and 5 of [RFC7589].

2.  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.

3.  Early Data

   Early data (aka 0-RTT data) is a mechanism defined in TLS 1.3
   [I-D.ietf-tls-rfc8446bis] that allows a client to send data ("early
   data") as part of the first flight of messages to a server.  Note
   that TLS 1.3 can be used without early data as per Appendix F.5 of
   [I-D.ietf-tls-rfc8446bis].  In fact, early data is permitted by TLS
   1.3 only when the client and server share a Pre-Shared Key (PSK),
   either obtained externally or via a previous handshake.  The client
   uses the PSK to authenticate the server and to encrypt the early
   data.

   As noted in Section 2.3 of [I-D.ietf-tls-rfc8446bis], the security
   properties for early data are weaker than those for subsequent TLS-
   protected data.  In particular, early data is not forward secret, and
   there is no protection against the replay of early data between
   connections.  Appendix E.5 of [I-D.ietf-tls-rfc8446bis] requires
   applications not use early data without a profile that defines its
   use.  This document specifies that NETCONF implementations that
   support TLS 1.3 MUST NOT use early data.

4.  Cipher Suites

   Implementations MUST support mutually authenticated TLS 1.2 [RFC5246]
   and they are, as specified in [RFC9325], recommended to support the
   cipher suites found in Section 4.2 of [RFC9325].

   Implementations MAY implement additional TLS 1.2 cipher suites that
   provide mutual authentication [RFC5246] and confidentiality as
   required by NETCONF [RFC6241].

   Implementations SHOULD support mutually authenticated TLS 1.3
   [I-D.ietf-tls-rfc8446bis] and, if implemented, MUST prefer to
   negotiate TLS 1.3 over earlier versions of TLS.

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   Implementations that support TLS 1.3 [I-D.ietf-tls-rfc8446bis] are
   REQUIRED to support the mandatory-to-implement cipher suites listed
   in Section 9.1 of [I-D.ietf-tls-rfc8446bis].

   Implementations that support TLS 1.3 MAY implement additional TLS
   cipher suites that provide mutual authentication and confidentiality,
   which are required for NETCONF [RFC6241].

5.  Security Considerations

   The Security Considerations of [RFC6241], [RFC7589], and [RFC9325]
   apply here as well.

   NETCONF implementations SHOULD follow the TLS recommendations given
   in [RFC9325].

   For implementations that support TLS 1.3, the Security Considerations
   of TLS 1.3 [I-D.ietf-tls-rfc8446bis] apply.

   As specified in [RFC7589], NETCONF over TLS requires mutual
   authentication.

   For implementations that support TLS 1.3 [I-D.ietf-tls-rfc8446bis]:

      TLS 1.3 mutual authentication is used to ensure that only
      authorized users and systems are able to view the NETCONF server's
      configuration and state or to modify the NETCONF server's
      configuration.  To this end, neither the client nor the server
      should establish a NETCONF over TLS 1.3 connection with an
      unknown, unexpected, or incorrectly identified peer; see Section 7
      of [RFC7589].  If deployments make use of a trusted list of
      Certification Authority (CA) certificates [RFC5280], then the
      listed CAs should only issue certificates to parties that are
      authorized to access the NETCONF servers.  Doing otherwise will
      allow certificates that were issued for other purposes to be
      inappropriately accepted by a NETCONF server.

   The Security Considerations of [RFC9525] apply to all implementations
   when the client checks the identity of the server, as is required in
   Section 6 of [RFC7589].

6.  IANA Considerations

   IANA is requested to add a reference to this document in the
   "netconf-tls" entry in the "Service Name and Transport Protocol Port
   Number Registry".  The updated registry entry would appear as
   follows:

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    Service Name:           netconf-tls
    Transport Protocol(s):  TCP
    Assignee:               IESG <iesg@ietf.org>
    Contact:                IETF Chair <chair@ietf.org>
    Description:            NETCONF over TLS
    Reference:              RFC 7589, [THIS RFC]
    Port Number:            6513

7.  Normative References

   [I-D.ietf-tls-rfc8446bis]
              Rescorla, E., "The Transport Layer Security (TLS) Protocol
              Version 1.3", Work in Progress, Internet-Draft, draft-
              ietf-tls-rfc8446bis-09, 7 July 2023,
              <https://datatracker.ietf.org/doc/html/draft-ietf-tls-
              rfc8446bis-09>.

   [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>.

   [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.2", RFC 5246,
              DOI 10.17487/RFC5246, August 2008,
              <https://www.rfc-editor.org/rfc/rfc5246>.

   [RFC5280]  Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
              Housley, R., and W. Polk, "Internet X.509 Public Key
              Infrastructure Certificate and Certificate Revocation List
              (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
              <https://www.rfc-editor.org/rfc/rfc5280>.

   [RFC6241]  Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
              and A. Bierman, Ed., "Network Configuration Protocol
              (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
              <https://www.rfc-editor.org/rfc/rfc6241>.

   [RFC7589]  Badra, M., Luchuk, A., and J. Schoenwaelder, "Using the
              NETCONF Protocol over Transport Layer Security (TLS) with
              Mutual X.509 Authentication", RFC 7589,
              DOI 10.17487/RFC7589, June 2015,
              <https://www.rfc-editor.org/rfc/rfc7589>.

   [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>.

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   [RFC9325]  Sheffer, Y., Saint-Andre, P., and T. Fossati,
              "Recommendations for Secure Use of Transport Layer
              Security (TLS) and Datagram Transport Layer Security
              (DTLS)", BCP 195, RFC 9325, DOI 10.17487/RFC9325, November
              2022, <https://www.rfc-editor.org/rfc/rfc9325>.

   [RFC9525]  Saint-Andre, P. and R. Salz, "Service Identity in TLS",
              RFC 9525, DOI 10.17487/RFC9525, November 2023,
              <https://www.rfc-editor.org/rfc/rfc9525>.

Acknowledgments

   We would like to thank Per Andersson, Jürgen Schönwälder, Jeff
   Hartley, Rob Wilton, and Qin Wu for their reviews.

Authors' Addresses

   Sean Turner
   sn3rd
   Email: sean@sn3rd.com

   Russ Housley
   Vigil Security, LLC
   516 Dranesville Road
   Herndon, VA,  20170
   United States of America
   Email: housley@vigilsec.com

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