I2RS working group                                              S. Hares
Internet-Draft                                                    Huawei
Intended status: Standards Track                              D. Migault
Expires: September 10, 2016                                   J. Halpern
                                                           March 9, 2016

                   I2RS Security Related Requirements


   This presents security-related requirements for the I2RS protocol for
   mutual authentication, transport protocols, data transfer and

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 10, 2016.

Copyright Notice

   Copyright (c) 2016 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
   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.

Hares, et al.          Expires September 10, 2016               [Page 1]

Internet-Draft         I2RS Security Requirements             March 2016

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  Definitions . . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Security Definitions  . . . . . . . . . . . . . . . . . .   3
     2.2.  I2RS Specific Definitions . . . . . . . . . . . . . . . .   6
   3.  Security-Related Requirements . . . . . . . . . . . . . . . .   7
     3.1.  Mutual authentication of an I2RS client and an I2RS Agent   8
     3.2.  Transport Requirements Based on Mutual Authentication . .   8
     3.3.  Data Confidentiality Requirements . . . . . . . . . . . .  10
     3.4.  Data Integrity Requirements . . . . . . . . . . . . . . .  10
     3.5.  Role-Based Data Model Security  . . . . . . . . . . . . .  11
   4.  Acknowledgement . . . . . . . . . . . . . . . . . . . . . . .  11
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  12
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  12
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  12
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  13

1.  Introduction

   The Interface to the Routing System (I2RS) provides read and write
   access to information and state within the routing process.  The I2RS
   client interacts with one or more I2RS agents to collect information
   from network routing systems.

   This document describes the requirements for the I2RS protocol in the
   security-related areas of mutual authentication of the I2RS client
   and agent, the transport protocol carrying the I2RS protocol
   messages, and the atomicity of the transactions.  These requirements
   align with the description of the I2RS architecture found in
   [I-D.ietf-i2rs-architecture] document which solves the problem
   described in [I-D.ietf-i2rs-problem-statement].

   [I-D.ietf-i2rs-ephemeral-state] discusses I2RS roles-based write
   conflict resolution in the ephemeral data store using the I2RS Client
   Identity, I2RS Secondary Identity and priority.  The draft
   [I-D.ietf-i2rs-traceability] describes the traceability framework and
   its requirements for I2RS.  The draft
   [I-D.ietf-i2rs-pub-sub-requirements] describes the requirements for
   I2RS to be able to publish information or have a remote client
   subscribe to an information data stream.

Hares, et al.          Expires September 10, 2016               [Page 2]

Internet-Draft         I2RS Security Requirements             March 2016

1.1.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in RFC 2119 [RFC2119].

2.  Definitions

2.1.  Security Definitions

   This document utilizes the definitions found in the following
   documents: [RFC4949] and [I-D.ietf-i2rs-architecture]

   Specifically, this document utilizes the following definitions:

   access control

      [RFC4949] defines access control as the following:

         1.  (I) Protection of system resources against unauthorized

         2.  (I) A process by which use of system resources is regulated
         according to a security policy and is permitted only by
         authorized entities (users, programs, processes, or other
         systems) according to that policy.  (See: access, access
         control service, computer security, discretionary access
         control, mandatory access control, role-based access control.)

         3.  (I) /formal model/ Limitations on interactions between
         subjects and objects in an information system.

         4.  (O) "The prevention of unauthorized use of a resource,
         including the prevention of use of a resource in an
         unauthorized manner."  [I7498-2]

         5.  (O) /U.S.  Government/ A system using physical, electronic,
         or human controls to identify or admit personnel with properly
         authorized access to a SCIF.


      [RFC4949] describes authentication as the process of verifying
      (i.e., establishing the truth of) an attribute value claimed by or
      for a system entity or system resource.  Authentication has two
      steps: identify and verify.

   Data Confidentiality

Hares, et al.          Expires September 10, 2016               [Page 3]

Internet-Draft         I2RS Security Requirements             March 2016

      [RFC4949] describes data confidentiality as having two properties:

         a) Data is not disclosed to system entities unless they have
         been authorized to know the data, and

         b) Data is not disclosed to unauthorized individuals, entities
         or processes.

      The key point is that confidentiality implies that the originator
      has the ability to authorize where the information goes.
      Confidentiality is important for both read and write scope of the

   Data Integrity

      [RFC4949] states data integrity includes:

         1.  (I) The property that data has not been changed, destroyed,
         or lost in an unauthorized or accidental manner. [...]

         2.  (O) "The property that information has not been modified or
         destroyed in an unauthorized manner."  [I7498-2]

   Data Privacy

      [RFC4949] describes data privacy as a synonym for data
      confidentiality.  This I2RS document will utilize data privacy as
      a synonym for data confidentiality.


      [RFC4949] (I) The collective aspect of a set of attribute values
      (i.e., a set of characteristics) by which a system user or other
      system entity is recognizable or known.  (See: authenticate,
      registration.  Compare: identifier.)


      [RFC4949] (I) A data object -- often, a printable, non-blank
      character string -- that definitively represents a specific
      identity of a system entity, distinguishing that identity from all
      others.  (Compare: identity.)

   Mutual Authentication

      [RFC4949] implies that mutual authentication exists between two
      interacting system entities.

Hares, et al.          Expires September 10, 2016               [Page 4]

Internet-Draft         I2RS Security Requirements             March 2016

      Mutual authentication in I2RS implies that both sides move from a
      state of mutual suspicion to to mutual authentication to trusted
      mutual communication after each system has been identified and
      validated by its peer system.


      [RFC4949] describes role as:

         1.  (I) A job function or employment position to which people
         or other system entities may be assigned in a system. [...]

         2.  (O) /Common Criteria/ A pre-defined set of rules
         establishing the allowed interactions between a user and the

      The I2RS uses the common criteria definition.

   role-based access control

      [RFC4949] describes role-based access control as: "A form of
      identity-based access control wherein the system entities that are
      identified and controlled are functional positions in an
      organization or process."

   security audit trail

      [RFC4949] describes a security audit trail as "A chronological
      record of system activities that is sufficient to enable the
      reconstruction and examination of the sequence environments and
      activities surrounding or leading to an operation, procedure, or
      event in a security-relevant transaction from inception to final

      Requirements to support a security audit is not covered in this

      [I-D.ietf-i2rs-traceability] describes traceability for I2RS
      interface and the I2RS protocol.  Traceability is not equivalent
      to a security audit trail.



      1.  (I) /information system/ A feeling of certainty (sometimes
          based on inconclusive evidence) either (a) that the system
          will not fail or (b) that the system meets its specifications

Hares, et al.          Expires September 10, 2016               [Page 5]

Internet-Draft         I2RS Security Requirements             March 2016

          (i.e., the system does what it claims to do and does not
          perform unwanted functions).  (See: trust level, trusted
          system, trustworthy system.  Compare: assurance.)

      2.  . (I) /PKI/ A relationship between a certificate user and a CA
          in which the user acts according to the assumption that the CA
          creates only valid digital certificates.  (Also referred as
          "trusted" in [RFC4949].)

2.2.  I2RS Specific Definitions

   I2RS protocol data integrity

      The transfer of data via the I2RS protocol has the property of
      data integrity described in [RFC4949].

   I2RS component protocols

      Protocols which are combined to create the I2RS protocol.

   I2RS Higher-level protocol

      The I2RS protocol exists as a higher-level protocol which combines
      combination of other protocols (NETCONF, RESTCONF, IPFIX, and
      others) within a specific I2RS client-agent relationship with a
      specific trust for ephemeral configurations, event, tracing,
      actions, and data flow interactions.  The protocols included in
      the I2RS protocol protocol are defined as I2RS component

   I2RS message

      is a complete data message of one of the I2RS component protocols.
      The I2RS component protocols may require multiple IP-packets to
      send one protocol message.

   I2RS multi-message atomicity

      An I2RS operation (read, write, event, action) must be contained
      within one I2RS message.  Each I2RS operation must be atomic.
      While it is possible to have an I2RS operation which is contained
      in multiple I2RS (E.g. write in multiple messages), this is not
      supported in order to simply the first version of I2RS.  Multiple-
      message atomicity of I2RS operations would be used in a roll-back
      of a grouping of commands (e.g. multiple writes).

   I2RS transaction

Hares, et al.          Expires September 10, 2016               [Page 6]

Internet-Draft         I2RS Security Requirements             March 2016

      is a unit of I2RS functionality.  Some examples of I2RS
      transactions are:

      *  The I2RS client issuing a read request to a I2RS agent, and the
         I2RS Agent responding to the read request

      *  The I2RS client issue a write of ephemeral configuration values
         into a data model, followed by the I2RS agent response to the

      *  An I2RS client may issue an action request, the I2RS agent
         responds to the action-request, and then responds when action
         is complete.  Actions can be single step processes or multiple
         step process.

      *  An I2RS client requests to receive an event notification, and
         the I2RS Agent sets up to send the events.

      *  An I2RS agent sends events to an I2RS Client on an existing

      An I2RS action may require multiple I2RS messages in order to
      complete a transation.

   I2RS secondary identifier

      the I2RS architecture document [I-D.ietf-i2rs-architecture]
      defines a secondary identity as the entity of some non-I2RS entity
      (e.g. application) which has requested a particular I2RS client
      perform an operation.  The I2RS secondary identifier represents
      this identity so it may be distinguished from all others.

3.  Security-Related Requirements

   The security for the I2RS protocol requires mutually authenticated
   I2RS clients and I2RS agents.  The I2RS client and I2RS agent using
   the I2RS protocol MUST be able to exchange data over a secure
   transport, but some functions may operate on a non-secure transport.
   The I2RS protocol MUST be able to provide atomicity of an I2RS
   transaction, but it is not required to have multi-message atomicity
   and roll-back mechanism transactions.  Multiple messages transactions
   may be impacted by the interdependency of data.  This section
   discusses the details of these security requirements.

Hares, et al.          Expires September 10, 2016               [Page 7]

Internet-Draft         I2RS Security Requirements             March 2016

3.1.  Mutual authentication of an I2RS client and an I2RS Agent

   The I2RS architecture [I-D.ietf-i2rs-architecture] sets the following

   o  SEC-REQ-01: All I2RS clients and I2RS agents MUST have an
      identity, and at least one unique identifier that uniquely
      identifies each party in the I2RS protocol context.

   o  SEC-REQ-02: The I2RS protocol MUST utilize these identifiers for
      mutual identification of the I2RS client and I2RS agent.

   o  SEC-REQ-03: An I2RS agent, upon receiving an I2RS message from a
      I2RS client, MUST confirm that the I2RS client has a valid

   o  SEC-REQ-04: The I2RS client, upon receiving an I2RS message from
      an I2RS agent, MUST confirm the I2RS agent has a valid identifier.

   o  SEC-REQ-05: Identifier distribution and the loading of these
      identifiers into I2RS agent and I2RS Client SHOULD occur outside
      the I2RS protocol.

   o  SEC-REQ-06: The I2RS protocol SHOULD assume some mechanism (IETF
      or private) will distribute or load identifiers so that the I2RS
      client/agent has these identifiers prior to the I2RS protocol
      establishing a connection between I2RS client and I2RS agent.

   o  SEC-REQ-07: Each Identifier MUST have just one priority.

   o  SEC-REQ-08: Each Identifier is associated with one secondary
      identifier during a particular I2RS transaction (e.g. read/write
      sequence), but the secondary identifier may vary during the time a
      connection between the I2RS client and I2RS agent is active.
      Since a single I2RS client may be use by multiple applications,
      the secondary identifier may vary as the I2RS client is utilize by
      different application each of whom have a unique secondary
      identity and identifier.

3.2.  Transport Requirements Based on Mutual Authentication

   SEC-REQ-09: The I2RS protocol MUST be able to transfer data over a
   secure transport and optionally MAY be able to transfer data over a
   non-secure transport.  A secure transport MUST provide data
   confidentiality, data integrity, and replay prevention.

   The default I2RS transport is a secure transport.

Hares, et al.          Expires September 10, 2016               [Page 8]

Internet-Draft         I2RS Security Requirements             March 2016

   A non-secure transport can be can be used for publishing telemetry
   data or other operational state that was specifically indicated to
   non-confidential in the data model in the Yang syntax.

   The configuration of ephemeral data in the I2RS Agent by the I2RS
   client SHOULD be done over a secure transport.  It is anticipated
   that the passing of most I2RS ephemeral state operational status
   SHOULD be done over a secure transport.  As
   [I-D.ietf-i2rs-ephemeral-state] notes data model MUST indicate
   whether the transport exchanging the data between I2RS client and
   I2RS agent is secure or insecure.  The default mode of transport is
   secure so data models SHOULD clearly annotate what data nodes can be
   passed over an insecure connection.

   SEC-REQ-10: A secure transport MUST be associated with a key
   management solution that can guarantee that only the entities having
   sufficient privileges can get the keys to encrypt/decrypt the
   sensitive data.  Per BCP107 [RFC4107] this key management system
   SHOULD be automatic, but MAY be manual in the following scenarios:

      a) The environment has limited bandwidth or high round-trip times.

      b) The information being protected has low value.

      c) The total volume of traffic over the entire lifetime of the
      long-term session key will be very low.

      d) The scale of the deployment is limited.

   Most I2RS environments (Clients and Agents) will not have the
   environment described by BCP107 [RFC4107] but a few I2RS use cases
   required limited non-secure light-weight telemetry messages that have
   these requirements.  An I2RS data model must indicate which portions
   can be served by manual key management.

   SEC-REQ-11: The I2RS protocol MUST be able to support multiple secure
   transport sessions providing protocol and data communication between
   an I2RS Agent and an I2RS client.  However, a single I2RS Agent to
   I2RS client connection MAY elect to use a single secure transport
   session or a single non-secure transport session.

   SEC-REQ-12: The I2RS Client and I2RS Agent protocol SHOULD implement
   mechanisms that mitigate DoS attacks

Hares, et al.          Expires September 10, 2016               [Page 9]

Internet-Draft         I2RS Security Requirements             March 2016

3.3.  Data Confidentiality Requirements

   SEC-REQ-13: In a critical infrastructure, certain data within routing
   elements is sensitive and read/write operations on such data MUST be
   controlled in order to protect its confidentiality.  For example,
   most carriers do not want a router's configuration and data flow
   statistics known by hackers or their competitors.  While carriers may
   share peering information, most carriers do not share configuration
   and traffic statistics.  To achieve this, access control to sensitive
   data needs to be provided, and the confidentiality protection on such
   data during transportation needs to be enforced.

3.4.  Data Integrity Requirements

   SEC-REQ-14: An integrity protection mechanism for I2RS SHOULD be able
   to ensure the following:

      1) The data being protected is not modified without detection
      during its transportation and

      2) The data is actually from where it is expected to come from

      3) The data is not repeated from some earlier interaction of the
      protocol.  That is, when both confidentiality and integrity of
      data is properly protected, it is possible to ensure that
      encrypted data is not modified or replayed without detection.

   SEC-REQ-15: The integrity that the message data is not repeated means
   that I2RS client to I2RS agent transport SHOULD protect against
   replay attack

   Requirements SEC-REQ-13 and SEC-REQ-14 are SHOULD requirements only
   because it is recognized that some I2RS Client to I2RS agent
   communication occurs over a non-secure channel.  The I2RS client to
   I2RS agent over a secure channel would implement these features.  In
   order to provide some traceability or notification for the non-secure
   protocol, SEC-REQ-16 suggests traceability and notification are
   important to include for any non-secure protocol.

   SEC-REQ-16: The I2RS message traceability and notification
   requirements requirements found in [I-D.ietf-i2rs-traceability] and
   [I-D.ietf-i2rs-pub-sub-requirements] SHOULD be supported in
   communication channel that is non-secure to trace or notify about
   potential security issues.

Hares, et al.          Expires September 10, 2016              [Page 10]

Internet-Draft         I2RS Security Requirements             March 2016

3.5.  Role-Based Data Model Security

   The I2RS Architecture [I-D.ietf-i2rs-architecture] defines a role or
   security role as specifying read, write, or notification access by a
   I2RS client to data within an agent's data model.

   SEC-REQ-17: The rules around what role is permitted to access and
   manipulate what information plus a secure transport (which protects
   the data in transit) SHOULD ensure that data of any level of
   sensitivity is reasonably protected from being observed by those
   without permission to view it, so that privacy requirements are met.

   SEC-REQ-18: Role security MUST work when multiple transport
   connections are being used between the I2RS client and I2RS agent as
   the I2RS architecture [I-D.ietf-i2rs-architecture] states.  These
   transport message streams may start/stop without affecting the
   existence of the client/agent data exchange.  TCP supports a single
   stream of data.  SCTP [RFC4960] provides security for multiple
   streams plus end-to-end transport of data.

   SEC-REQ-19: I2RS clients MAY be used by multiple applications to
   configure routing via I2RS agents, receive status reports, turn on
   the I2RS audit stream, or turn on I2RS traceability.  Application
   software using I2RS client functions may host multiple secure
   identities, but each connection will use only one identifier with one
   priority.  Therefore, the security of each I2RS Client to I2RS Agent
   connection is unique.

   Please note the security of the application to I2RS client connection
   is outside of the I2RS protocol or I2RS interface.

4.  Acknowledgement

   The authors would like to thank Wes George, Ahmed Abro, Qin Wu, Eric
   Yu, Joel Halpern, Scott Brim, Nancy Cam-Winget, DaCheng Zhang, Alia
   Atlas, and Jeff Haas for their contributions to the I2RS security
   requirements discussion and this document.  The authors would like to
   thank Bob Moskowitz for his review of the requirements.

5.  IANA Considerations

   This draft includes no request to IANA.

6.  Security Considerations

   This is a document about security requirements for the I2RS protocol
   and data modules.  The whole document is security considerations.

Hares, et al.          Expires September 10, 2016              [Page 11]

Internet-Draft         I2RS Security Requirements             March 2016

7.  References

7.1.  Normative References

              Atlas, A., Halpern, J., Hares, S., Ward, D., and T.
              Nadeau, "An Architecture for the Interface to the Routing
              System", draft-ietf-i2rs-architecture-13 (work in
              progress), February 2016.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,

   [RFC4107]  Bellovin, S. and R. Housley, "Guidelines for Cryptographic
              Key Management", BCP 107, RFC 4107, DOI 10.17487/RFC4107,
              June 2005, <http://www.rfc-editor.org/info/rfc4107>.

7.2.  Informative References

              Haas, J. and S. Hares, "I2RS Ephemeral State
              Requirements", draft-ietf-i2rs-ephemeral-state-03 (work in
              progress), March 2016.

              Atlas, A., Nadeau, T., and D. Ward, "Interface to the
              Routing System Problem Statement", draft-ietf-i2rs-
              problem-statement-10 (work in progress), February 2016.

              Voit, E., Clemm, A., and A. Prieto, "Requirements for
              Subscription to YANG Datastores", draft-ietf-i2rs-pub-sub-
              requirements-05 (work in progress), February 2016.

              Clarke, J., Salgueiro, G., and C. Pignataro, "Interface to
              the Routing System (I2RS) Traceability: Framework and
              Information Model", draft-ietf-i2rs-traceability-07 (work
              in progress), February 2016.

   [RFC4949]  Shirey, R., "Internet Security Glossary, Version 2",
              FYI 36, RFC 4949, DOI 10.17487/RFC4949, August 2007,

Hares, et al.          Expires September 10, 2016              [Page 12]

Internet-Draft         I2RS Security Requirements             March 2016

   [RFC4960]  Stewart, R., Ed., "Stream Control Transmission Protocol",
              RFC 4960, DOI 10.17487/RFC4960, September 2007,

Authors' Addresses

   Susan Hares
   7453 Hickory Hill
   Saline, MI  48176

   Email: shares@ndzh.com

   Daniel Migault
   8400 boulevard Decarie
   Montreal, QC  HAP 2N2

   Email: daniel.migault@ericsson.com

   Joel Halpern

   Email: joel.halpern@ericsson.com

Hares, et al.          Expires September 10, 2016              [Page 13]