Internet Engineering Task Force S. Hollenbeck
Internet-Draft Verisign Labs
Intended status: Standards Track N. Kong
Expires: October 06, 2013 CNNIC
April 04, 2013
Security Services for the Registration Data Access Protocol
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.
Status of This Memo
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This Internet-Draft will expire on October 06, 2013.
Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions Used in This Document . . . . . . . . . . . . . . 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 . . . . . . . . . . . . . . . . . . . . . . 5
3.4. Data Confidentiality . . . . . . . . . . . . . . . . . . 6
3.5. Data Integrity . . . . . . . . . . . . . . . . . . . . . 6
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
5. Security Considerations . . . . . . . . . . . . . . . . . . . 7
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
7.1. Normative References . . . . . . . . . . . . . . . . . . 8
7.2. Informative References . . . . . . . . . . . . . . . . . 9
Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
The Registration Data Access Protocol (RDAP) core is specified in two
documents: "Registration Data Access Protocol Lookup Format"
[I-D.ietf-weirds-rdap-query] and "JSON Responses for the Registration
Data Access 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 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
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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
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.
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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.
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
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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.
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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.
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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, data confidentiality,
and data integrity. Non-repudiation services were also considered
and ultimately rejected due to a lack of 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.
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6. Acknowledgements
The authors would like to acknowledge the following individuals for
their contributions to this document: Marc Blanchet, Jean-Philippe
Dionne, Andrew 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
Registration Data Access Protocol (RDAP)", draft-ietf-
weirds-json-response-02 (work in progress), January 2013.
[I-D.ietf-weirds-rdap-query]
Newton, A. and S. Hollenbeck, "Registration Data Access
Protocol Lookup Format", draft-ietf-weirds-rdap-query-03
(work in progress), March 2013.
[OpenID] OpenID Foundation, "OpenID Authentication 2.0 - 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.M., Hostetler, J.L., Lawrence,
S.D., Leach, 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., 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.
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[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/
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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
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