INTERNET-DRAFT Adam W. Montville Intended Status: Standards Track (Tripwire, Inc.) Expires: June 17, 2013 December 14, 2012 IODEF Enumeration Reference Format draft-montville-mile-enum-reference-format-02 Abstract The Incident Object Description Exchange Format [IODEF] provides a Reference class used to reference external entities (such as enumeration identifiers). However, the method of external entity identification has been left unstructured. This document describes a method to provide structure for referencing external entities for the [IODEF] Reference class. Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/1id-abstracts.html The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html Copyright and License Notice Copyright (c) 2012 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 Adam W. Montville Expires June 17, 2013 [Page 1] INTERNET DRAFT IODEF Enumeration Reference Format December 14, 2012 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. Table of Contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Referencing External Enumerations . . . . . . . . . . . . . . 3 3 Security Considerations . . . . . . . . . . . . . . . . . . . . 6 4 IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 5 References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 5.1 Normative References . . . . . . . . . . . . . . . . . . . 7 5.2 Informative References . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7 Adam W. Montville Expires June 17, 2013 [Page 2] INTERNET DRAFT IODEF Enumeration Reference Format December 14, 2012 1 Introduction There is an identified need to specify a format to include relevant enumeration values in an IODEF document. It is anticipated that this requirement will exist in other standardization efforts within several IETF Working Groups, but the scope of this document pertains solely to [IODEF]. 1.1 Terminology 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. Referencing External Enumerations The need is to place enumeration identifiers and their references in [IODEF]'s Reference class. There are several ways to accomplish this goal, but one that seems the most appropriate at this point is to require a specific format for the ReferenceName string of the [IODEF] Reference class, such that an IANA table can be used to catalog a variety of reference types. +------------------+ | Reference | +------------------+ | |<>----------[ ReferenceName ] | |<>--{0..*}--[ URL ] | |<>--{0..*}--[ Description ] +------------------+ FIGURE 1: [IODEF] Reference Class Per [IODEF] the ReferenceName is of type ML_STRING. This becomes problematic when specific references, especially enumerations such as CEE, CVE, CCE, and so on, are referenced - how is an implementer to know which type of reference this is, and thus how to parse it? One solution, presented here, is to require that ReferenceName follow a particular format. 2.1 Reference Name Format The format of the ReferenceName MUST follow the form of id_type:version:id Where id_type is an IANA-registered type having the form Adam W. Montville Expires June 17, 2013 [Page 3] INTERNET DRAFT IODEF Enumeration Reference Format December 14, 2012 And where version is an IANA-registered type having the form And where id is the actual enumeration identifier string. The IANA Considerations section of this document provides details for and . This format allows the to be associated with the id rather than the id_type. By requiring that a specific type and version be associated with the identifier, an implementer can look up the type in an IANA table to understand exactly what the identifier in ReferenceName is and how s/he may expect that identifier to be structured. 2.2 Reference Example The operation of this method can be described using a fictitious example. Assume a Reference class as described in the Section 2 introduction and an enumeration of formatted strings used to identify Concept X. Then, the string format of Concept X Identifiers would be registered with IANA (see Section 4), such that implementations of the Reference class understand how to handle the formatted string. CXI:1.0:CXI-1234-XYZ http://cxi.example.com Foo Information in the IANA table (see Section 4) would include: Full Name: Concept X Identifier Abbreviation: CXI Version: 1.0 Specification URI: http://cxi.example.com/spec_url 2.3 Reference Method Applicability While the scope of this document pertains to [IODEF], it should be readily apparent that any standard needing to reference an enumeration identified by a specially formatted string can use this method of providing structure after the standard has been published. In effect, this method provides a standardized interface for enumerations, thus allowing a loose coupling between Adam W. Montville Expires June 17, 2013 [Page 4] INTERNET DRAFT IODEF Enumeration Reference Format December 14, 2012 a given standard and the enumeration identifiers it needs to reference now and in the future. Adam W. Montville Expires June 17, 2013 [Page 5] INTERNET DRAFT IODEF Enumeration Reference Format December 14, 2012 3 Security Considerations None. 4 IANA Considerations This document specifies an identifier format for the [IODEF] ReferenceName string of the Reference class. Registration request for the IODEF Enumeration Reference Format: Name of the Registry: "Enumeration Reference Type Identifiers" The registry is intended to enable enumeration value additions to attributes of a given reference class of an IETF standard, for example, the Reference class of the IODEF schema. Note that certain name requests should not be permitted as either Full Name or Abbreviation entries for the requested IANA table. For example, the following list should not be permitted: foo, bar, example.com. It is anticipated that the Expert Review process will flag any additional undesired Full Name or Abbreviation issues. Fields to record in the registry: Full Name: The full name of the enumeration as a string Abbreviation: The abbreviation of the enumeration as a string, e.g. a short initialization is encouraged Version: The version of the enumeration as a string, e.g. dot- separated numbers are a good idea Specification URI: A list of one or more URIs [RFC3986] from which the registered specification can be obtained. The registered specification MUST be readily and publicly available from that URI. Initial registry contents: None. Allocation Policy: Expert Review [RFC5226] and Specification Required [RFC5226] The Designated Expert is expected to consult with the MILE (Managed Incident Lightweight Exchange) working group or its successor if any such WG exists (e.g., via email to the working group's mailing list). The Designated Expert is expected to review the request and validate Adam W. Montville Expires June 17, 2013 [Page 6] INTERNET DRAFT IODEF Enumeration Reference Format December 14, 2012 the appropriateness of the enumeration for the attribute. If a specification is associated with the request, it MUST be reviewed by the Designated Expert. 5 References 5.1 Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [IODEF] Danyliw, R., Meijer, J., and Y. Demchenko, "The Incident Object Description Exchange Format", RFC 5070, December 2007. [3986] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 5226, May 2008. 5.2 Informative References None. Authors' Addresses Adam W. Montville Tripwire, Inc. 101 SW Main Street Suite 1500 Portland, OR 97204 EMail: amontville@tripwire.com Adam W. Montville Expires June 17, 2013 [Page 7]