Internet Engineering Task Force                            S. Hollenbeck
Internet-Draft                                             Verisign Labs
Intended status: Standards Track                                 N. Kong
Expires: May 30, October 06, 2013                                          CNNIC
                                                       November 26, 2012
                                                          April 04, 2013

      Security Services for the Registration Data Access Protocol
                     draft-ietf-weirds-rdap-sec-01
                     draft-ietf-weirds-rdap-sec-02

Abstract

   The Registration Data Access Protocol (RDAP) provides "RESTful" web
   services to retrieve registration metadata from domain name and
   regional internet registries.  This document describes information
   security services, specific requirements for RDAP, and approaches to
   provide RDAP security services.

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   document authors.  All rights reserved.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3   2
   2.  Conventions Used in This Document . . . . . . . . . . . . . . . 3   2
     2.1.  Acronyms and Abbreviations  . . . . . . . . . . . . . . . .   3
   3.  Information Security Services and RDAP  . . . . . . . . . . . .   3
     3.1.  Authentication  . . . . . . . . . . . . . . . . . . . . . .   3
       3.1.1.  Federated Authentication  . . . . . . . . . . . . . . .   4
     3.2.  Authorization . . . . . . . . . . . . . . . . . . . . . . .   5
     3.3.  Availability  . . . . . . . . . . . . . . . . . . . . . . . 6   5
     3.4.  Data Confidentiality  . . . . . . . . . . . . . . . . . .   6
     3.5.  Data Integrity  . . . . . . . . . . . . . . . . . . . . .   6
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6   7
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 6   7
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 7   8
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 7   8
     7.1.  Normative References  . . . . . . . . . . . . . . . . . . . 7   8
     7.2.  Informative References  . . . . . . . . . . . . . . . . . . 8   9
   Appendix A.  Change Log . . . . . . . . . . . . . . . . . . . . . . 8   9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 8   9

1.  Introduction

   The Registration Data Access Protocol (RDAP) core is specified in two
   documents: "Unified Registration "Registration Data Access Protocol Query Lookup Format"
   [I-D.ietf-weirds-rdap-query] and "JSON Responses for the Registry Registration
   Data Access Protocol" Protocol (RDAP)" [I-D.ietf-weirds-json-response].  One
   goal of RDAP is to provide security services that do not exist in the
   WHOIS [RFC3912] protocol, including authentication, authorization,
   availability, data confidentiality, and data confidentiality. integrity.

   This document describes each of these security services from the
   perspective of RDAP requirements and applicability.  Where
   applicable, informational references to requirements for a WHOIS
   replacement service [RFC3707] are noted.

2.  Conventions Used in This Document
   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 RFC 2119 [RFC2119].

2.1.  Acronyms and Abbreviations

      DNR: Domain Name Registry

      RDAP: Registration Data Access Protocol

      RIR: Regional Internet Registry

3.  Information Security Services and RDAP

   RDAP itself does not include native security services.  Instead, RDAP
   relies on features that are available in other protocol layers to
   provide needed security services including authentication,
   authorization, availability, data confidentiality, and data confidentiality.
   integrity.  A description of each of these security services can be
   found in RFC 4949 [RFC4949].  No requirements have been identified
   for other security services.

3.1.  Authentication

   WHOIS does not provide features to identify and authenticate clients.
   As noted in section 3.1.4.2 of RFC 3707 [RFC3707], there is utility
   in allowing server operators to offer "varying degrees of access
   depending on policy and need".  Clients have to be identified and
   authenticated to provide that utility.

   REQUIREMENT: RDAP MUST include an authentication framework that can
   accommodate anonymous access as well as verification of identities
   using a range of authentication methods and credential services.

   REQUIREMENT: The RDAP authentication framework MUST use
   authentication methods that are fully specified and available to
   existing HTTP clients and servers.

   REQUIREMENT: The RDAP authentication framework MUST be capable of
   supporting future authentication methods defined for use with HTTP.

   APPROACH: RDAP clients and servers MUST implement the authentication
   framework specified in RFC 2617 [RFC2617].  The "basic" scheme can be
   used to send a client's user name and password to a server in
   plaintext, based64-encoded form.  The "digest" scheme can be used to
   authenticate a client without exposing the client's plaintext
   password.  If the "basic" scheme is used another protocol (such as
   HTTP Over TLS [RFC2818]) MUST be used to protect the client's
   credentials from disclosure while in transit (see Section 3.4).

   The Transport Layer Security Protocol [RFC5246] includes an optional
   feature to identify and authenticate clients who possess and present
   a valid X.509 digital certificate [RFC5280].  Support for this
   feature is OPTIONAL.

3.1.1.  Federated Authentication

   The traditional client-server authentication model requires clients
   to maintain distinct credentials for every RDAP server.  This
   situation can become unwieldy as the number of RDAP servers
   increases.  Federated authentication mechanisms allow clients to use
   one credential to access multiple RDAP servers and reduce client
   credential management complexity.  RDAP MAY include a federated
   authentication mechanism that permits a client to access multiple
   RDAP servers in the same federation with one credential.

   REQUIREMENT:

   Federated authentication mechanisms used by RDAP are OPTIONAL.  If
   used, they MUST be fully supported by HTTP.

   POSSIBLE APPROACH: The OAuth authorization framework [RFC6749]
   describes a method for users to access protected web resources
   without having to hand out their credentials.  Instead, clients
   supply access tokens issued by an authorization server with the
   permission of the resource owner.  Using OAuth, multiple RDAP servers
   can form a federation and the clients can access any server in the
   same federation by providing one credential registered in any server
   in that federation.  The OAuth authorization framework is designed
   for use with HTTP and thus can be used with RDAP.

   POSSIBLE APPROACH: OpenID [OpenID] is a decentralized single sign-on
   authentication system that allows users to log in at web sites with
   one ID instead of having to create multiple unique accounts.  OpenID
   is decentralized.  An end user can freely choose which OpenID
   provider to use, and can preserve their Identifier if they switch
   OpenID providers.  [To be discussed: Is it possible to introduce
   OpenID into RDAP?]

   POSSIBLE APPROACH: Section 7.4.6 of the Transport Layer Security
   Protocol [RFC5246] describes the specification of a client
   certificate.  Clients who possess and present a valid X.509 digital
   certificate, issued by an entity called "Certification Authority"
   (CA), could be identified and authenticated by a server who trusts
   the corresponding CA.  A certificate authentication method can be
   used to achieve federated authentication in which multiple RDAP
   servers all trust the same CAs and then any client with a certificate
   issued by a trusted CA can access any RDAP server in the federation.
   This certificate-based mechanism is supported by HTTPS and can be
   introduced into RDAP.

3.2.  Authorization

   WHOIS does not provide services to grant different levels of access
   to clients based on a client's authenticated identity.  As noted in
   section 3.1.4.2 of RFC 3707 [RFC3707], there is utility in allowing
   server operators to offer "varying degrees of access depending on
   policy and need".  Access control decisions can be made once a
   client's identity has been established and authenticated (see
   Section 3.1).

   REQUIREMENT: RDAP MUST include an authorization framework that is
   capable of providing granular (per registration data object) access
   controls according to the policies of the operator.

   APPROACH: Server operators will offer varying degrees of access
   depending on policy and need in conjunction with the authentication
   methods described in Section 3.1.  Some examples:

   -  Clients will be allowed access only to data for which they have a
      relationship.

   -  Unauthenticated or anonymous access status may not yield any
      contact information.

   -  Full access may be granted to a special group of authenticated
      clients.

   The type of access allowed by a server will most likely vary from one
   operator to the next.

3.3.  Availability

   An RDAP service has to be available to be useful.  There are no RDAP-
   unique requirements to provide availability, but as a general
   security consideration a service operator needs to be aware of the
   issues associated with denial of service.  A thorough reading of RFC
   4732 [RFC4732] is RECOMMENDED.

   An RDAP service MAY use a throttling mechanism to limit the number of
   queries that a single client can send in a given period of time.  If
   used, the server SHOULD return a 429 response code as described in
   RFC 6585 [RFC6585].  A client that receives a 429 response SHOULD
   decrease its query rate, and honor the Retry-After header if one is
   present.

3.4.  Data Confidentiality

   WHOIS does not provide the ability to encrypt data while in transit
   to protect it from inadvertent disclosure.  Web services commonly use
   HTTP Over TLS [RFC2818] to provide that protection.

   REQUIREMENT: RDAP or a protocol layer used by RDAP MUST include
   features to protect plaintext client credentials used for client
   authentication.

   REQUIREMENT: The data confidentiality methods used by RDAP MUST be
   fully specified and available to existing HTTP clients and servers.

   REQUIREMENT: RDAP MUST be capable of supporting future data
   confidentiality methods defined for use with HTTP.

   OPTION: RDAP or a protocol layer used by RDAP MAY include features to
   encrypt client-server data exchanges.

   APPROACH: As noted in Section 3.1, the HTTP "basic" authentication
   scheme can be used to authenticate a client.  When this scheme is
   used HTTP Over TLS [RFC2818] MUST be used to protect the client's
   credentials from disclosure while in transit.  HTTP Over TLS MAY also
   be used to protect client-server data exchanges if the policy of the
   server operator requires encryption.  There are no current
   requirements for object-level encryption, but RDAP MUST NOT preclude
   support for this feature in the future.

3.5.  Data Integrity

   WHOIS does not provide the ability to protect data from modification
   while in transit.  Web services commonly use HTTP Over TLS [RFC2818]
   to provide that protection.  Digital signatures as described in RFC
   4949 [RFC4949] are also used to provide data integrity.  Note that
   this security service is often mistakenly associated with policy
   requirements focused on data accuracy; those requirements are out of
   scope for this protocol.  The most specific need for this service is
   to provide assurance that HTTP redirection hints [RFC2616] are not
   modified.

   REQUIREMENT: RDAP or a protocol layer used by RDAP MUST include
   features to protect HTTP 30x redirection hints from modification.

   REQUIREMENT: The data integrity methods used by RDAP MUST be fully
   specified and available to existing HTTP clients and servers.

   OPTION: RDAP or a protocol layer used by RDAP MAY include features to
   provide message integrity checks.

   REQUIREMENT: RDAP MUST be capable of supporting future JSON data
   integrity methods defined for use with HTTP.

   OPTION: RDAP or a protocol layer used by RDAP MAY include features to
   provide data integrity by signing JSON-encoded objects.

   APPROACH: HTTP Over TLS MAY be used to protect client-server data
   exchanges if the policy of the server operator requires message
   integrity.  There are no current requirements for object-level data
   signing, but RDAP MUST NOT preclude support for this feature in the
   future.

4.  IANA Considerations

   This document does not specify any IANA actions.  This section can be
   removed if this document is published as an RFC.

5.  Security Considerations

   One of the goals of RDAP is to provide security services that do not
   exist in the WHOIS protocol.  This document describes the security
   services provided by RDAP and associated protocol layers, including
   authentication, authorization, availability, and data
   confidentiality.  Data integrity confidentiality,
   and non-repudiation data integrity.  Non-repudiation services were also considered
   and ultimately rejected.

   Data integrity: No requirements for data integrity have been
   identified.  This security service is often mistakenly associated
   with policy requirements focused on data accuracy, but those
   requirements are out of scope for this protocol.  Data integrity
   could be provided by signing JSON-encoded objects.  RDAP MUST NOT
   preclude support for this feature in the future.

   Non-repudiation: No requirements for non-repudiation with proof or
   origin or proof rejected due to a lack of delivery have been identified. requirements.  There are,
   however, currently-deployed WHOIS servers that can return signed
   responses that provide non-repudiation with proof of origin.  RDAP
   MUST NOT preclude support for this feature in the future.

   As an HTML-based protocol RDAP is susceptible to code injection
   attacks.  Code injection refers to adding code into a computer system
   or program to alter the course of execution.  There are many types of
   code injection, including SQL injection, dynamic variable or function
   injection, include file injection, shell injection, and html-script
   injection among others.  Data confidentiality and integrity services
   provide a measure of defense against man-in-the-middle injection
   attacks, but vulnerabilities in both client- and server-side software
   make it possible for injection attacks to succeed.

6.  Acknowledgements

   The authors would like to acknowledge the following individuals for
   their contributions to this document: Marc Blanchet, Jean-Philippe
   Dionne, Andrew Newton. Newton, and Linlin Zhou.

7.  References

7.1.  Normative References

   [I-D.ietf-weirds-json-response]
              Newton, A. and S. Hollenbeck, "JSON Responses for the
              Registy
              Registration Data Access Protocol (RDAP)",
              draft-ietf-weirds-json-response-00 draft-ietf-
              weirds-json-response-02 (work in progress),
              September 2012. January 2013.

   [I-D.ietf-weirds-rdap-query]
              Newton, A. and S. Hollenbeck, "Unified Registration "Registration Data Access
              Protocol Query Lookup Format",
              draft-ietf-weirds-rdap-query-01 draft-ietf-weirds-rdap-query-03
              (work in progress),
              November 2012. March 2013.

   [OpenID]   OpenID Foundation, "OpenID Authentication 2.0 - Final", Final ",
              December 2007, <http://specs.openid.net/auth/2.0>.

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

   [RFC2616]  Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
              Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
              Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.

   [RFC2617]  Franks, J., Hallam-Baker, P., P.M., Hostetler, J., J.L., Lawrence, S.,
              S.D., Leach, P., P.J., Luotonen, A., and L. Stewart, "HTTP
              Authentication: Basic and Digest Access Authentication",
              RFC 2617, June 1999.

   [RFC2818]  Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.

   [RFC4732]  Handley, M., Rescorla, E., and IAB, "Internet Denial-of-
              Service Considerations", RFC 4732, December 2006.

   [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.2", RFC 5246, August 2008.

   [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, May 2008.

   [RFC6585]  Nottingham, M. and R. Fielding, "Additional HTTP Status
              Codes", RFC 6585, April 2012.

   [RFC6749]  Hardt, D., "The OAuth 2.0 Authorization Framework", RFC
              6749, October 2012.

7.2.  Informative References

   [RFC3707]  Newton, A., "Cross Registry Internet Service Protocol
              (CRISP) Requirements", RFC 3707, February 2004.

   [RFC3912]  Daigle, L., "WHOIS Protocol Specification", RFC 3912,
              September 2004.

   [RFC4949]  Shirey, R., "Internet Security Glossary, Version 2", RFC
              4949, August 2007.

Appendix A.  Change Log

   Initial -00:  Adopted as working group document.
   -01:  Extensive text additions and revisions based on in-room
      discussion at IETF-85.  Sections for data integrity and non-
      repudiation have been removed due to a lack of requirements, but
      both topics are now addressed in the Security Considerations
      section.
   -02:  Fixed document names in the Introduction.  Modified text in
      Section 3.1.1 to clarify requirement.  Added text to Section 3.3
      to describe rate limiting.  Added new data integrity section.
      Updated security considerations to describe injection attacks.

Authors' Addresses

   Scott Hollenbeck
   Verisign Labs
   12061 Bluemont Way
   Reston, VA  20190
   US

   Email: shollenbeck@verisign.com
   URI:   http://www.verisignlabs.com/
   Ning Kong
   China Internet Network Information Center
   4 South 4th Street, Zhongguancun, Haidian District
   Beijing  100190
   China

   Phone: +86 10 5881 3147
   Email: nkong@cnnic.cn