| Security Automation and Continuous Monitoring | M. Cokus |
| Internet-Draft | D. Haynes |
| Intended status: Informational | D. Rothenberg |
| Expires: September 8, 2016 | The MITRE Corporation |
| J. Gonzalez | |
| Department of Homeland Security | |
| March 7, 2016 |
OVAL(R) Directives Model
draft-rothenberg-sacm-oval-directives-model-00
This document specifies Version 5.11.1 of the OVAL Directives Model which defines the constructs used to tailor the level of detail contained within a set of OVAL Results.
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 8, 2016.
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.
The Open Vulnerability and Assessment Language (OVAL) [OVAL-WEBSITE] is an international, information security community effort to standardize how to assess and report upon the machine state of systems. For over ten years, OVAL has been developed in collaboration with any and all interested parties to promote open and publicly available security content and to standardize the representation of this information across the entire spectrum of security tools and services.
OVAL provides an established framework for making assertions about a system's state by standardizing the three main steps of the assessment process: representing the current machine state; analyzing the system for the presence of the specified machine state; and representing the results of the assessment which facilitates collaboration and information sharing among the information security community and interoperability among tools.
This draft is the part of the OVAL contribution to the IETF SACM WG that standardizes the representation of the results of an assessment. It is intended to serve as a starting point for the endpoint posture assessment data modeling needs of SACM specifically a capability to specify the level of detail in Evaluation Results.
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].
The OVAL Directives Model is used to control what result information is included in the OVAL Results as well as specify its level of detail.
| Property | Type | Count | Description |
|---|---|---|---|
| generator | oval:GeneratorType | 1 | Information regarding the generation of the OVAL Directives content. The timestamp property of the generator MUST represent the time at which the oval_directives was created. |
| directives | oval-res:DefaultDirectivesType | 1 | Describes the default set of directives that specify the results that have been included in the OVAL Results. |
| class_directives | oval-res:ClassDirectivesType | 0..5 | Describes the set of directives that specify the class-specific results that have been included in the OVAL Results. |
| signature | ext:Signature | 0..1 | Mechanism to ensure the integrity and authenticity of the OVAL Directives content. |
The XML Schema that implements this OVAL Directives Model can be found below.
<?xml version="1.0" encoding="utf-8"?>
<xsd:schema
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:oval="http://oval.mitre.org/XMLSchema/oval-common-5"
xmlns:oval-res=
"http://oval.mitre.org/XMLSchema/oval-results-5"
xmlns:ds="http://www.w3.org/2000/09/xmldsig#"
xmlns:sch="http://purl.oclc.org/dsdl/schematron"
xmlns:oval-dir=
"http://oval.mitre.org/XMLSchema/oval-directives-5"
targetNamespace=
"http://oval.mitre.org/XMLSchema/oval-directives-5"
elementFormDefault="qualified" version="5.11">
<xsd:import namespace=
"http://oval.mitre.org/XMLSchema/oval-common-5"
schemaLocation="oval-common-schema.xsd"/>
<xsd:import namespace=
"http://oval.mitre.org/XMLSchema/oval-results-5"
schemaLocation="oval-results-schema.xsd"/>
<xsd:import
namespace="http://www.w3.org/2000/09/xmldsig#"
schemaLocation="xmldsig-core-schema.xsd"/>
<xsd:annotation>
<xsd:documentation>The following is a
description of the elements, types,
and attributes that compose the
core schema for encoding Open
Vulnerability and Assessment
Language (OVAL) Directives. Each of
the elements, types, and attributes
that make up the Core Directives
Schema are described in detail and
should provide the information
necessary to understand what each
object represents. This document is
intended for developers and assumes
some familiarity with XML. A high
level description of the
interaction between these objects
is not outlined
here.</xsd:documentation>
<xsd:appinfo>
<schema>Core Directives</schema>
<version>5.11.1</version>
<date>4/22/2015 09:00:00 AM</date>
<terms_of_use>Copyright (C) 2010 United States
Government. All Rights Reserved.</terms_of_use>
<sch:ns prefix="oval-dir" uri=
"http://oval.mitre.org/XMLSchema/
oval-directives-5"
/>
</xsd:appinfo>
</xsd:annotation>
<!-- ================================================== -->
<!-- ================================================== -->
<!-- ================================================== -->
<xsd:element name="oval_directives">
<xsd:annotation>
<xsd:documentation>The
oval_directives element is the
root of an OVAL Directive
Document. Its purpose is to
bind together the generator
and the set of directives
contained in the document. The
generator section must be
present and provides
information about when the
directives document was
compiled and under what
version. The optional
Signature element allows an
XML Signature as defined by
the W3C to be attached to the
document. This allows
authentication and data
integrity to be provided to
the user. Enveloped signatures
are supported. More
information about the official
W3C Recommendation regarding
XML digital signatures can be
found at
http://www.w3.org/TR/xmldsig-core/.
</xsd:documentation>
</xsd:annotation>
<xsd:complexType>
<xsd:sequence>
<xsd:element name="generator"
type="oval:GeneratorType">
<xsd:annotation>
<xsd:documentation>The
required generator
section provides
information about when
the directives document
was compiled and under
what
version.</xsd:documentation>
</xsd:annotation>
</xsd:element>
<xsd:element name="directives"
type="oval-res:DefaultDirectivesType">
<xsd:annotation>
<xsd:documentation>The
required directives
section presents flags
describing what
information must be been
included in an oval
results document. This
element represents the
default set of
directives. These
directives apply to all
classes of definitions
for which there is not a
class specific set of
directives.</xsd:documentation>
</xsd:annotation>
</xsd:element>
<xsd:element
name="class_directives"
type="oval-res:ClassDirectivesType"
minOccurs="0"
maxOccurs="5">
<xsd:annotation>
<xsd:documentation>The
optional class_directives
section presents flags
describing what
information has been
included in the results
document for a specific
OVAL Definition class.
The directives for a
particlar class override
the default
directives.</xsd:documentation>
</xsd:annotation>
</xsd:element>
<xsd:element
ref="ds:Signature"
minOccurs="0"
maxOccurs="1">
<xsd:annotation>
<xsd:documentation>The
optional Signature
element allows an XML
Signature as defined by
the W3C to be attached to
the document. This allows
authentication and data
integrity to be provided
to the user. Enveloped
signatures are supported.
More information about
the official W3C
Recommendation regarding
XML digital signatures
can be found at
http://www.w3.org/TR/xmldsig-core/.
</xsd:documentation>
</xsd:annotation>
</xsd:element>
</xsd:sequence>
</xsd:complexType>
<xsd:unique name="UniqueDirectiveClass">
<xsd:annotation>
<xsd:documentation>The class
attribute on
class_directives must be
unique.</xsd:documentation>
</xsd:annotation>
<xsd:selector
xpath="oval-dir:class_directives"/>
<xsd:field xpath="@class"/>
</xsd:unique>
</xsd:element>
<!-- ================================================== -->
<!-- =================== GENERATOR ================== -->
<!-- ================================================== -->
<!--
The GeneratorType is defined by the
oval-common-schema. Please refer to that
documentation for a description of the complex type.
-->
<!-- ================================================== -->
<!-- ================= DIRECTIVES =================== -->
<!-- ================================================== -->
<!--
The DefaultDirectivesType is defined by the
oval-results-schema. Please refer to that
documentation for a description of the complex type.
-->
<!-- ================================================== -->
<!-- ================ DIRECTIVES ==================== -->
<!-- ================================================== -->
<!--
The ClassDirectivesType is defined by the
oval-results-schema. Please refer to that
documentation for a description of the complex type.
-->
</xsd:schema>
Copyright (C) 2010 United States Government. All Rights Reserved.
DHS, on behalf of the United States, owns the registered OVAL trademarks, identifying the OVAL STANDARDS SUITE and any component part, as that suite has been provided to the IETF Trust. A "(R)" will be used in conjunction with the first use of any OVAL trademark in any document or publication in recognition of DHS's trademark ownership.
The authors wish to thank DHS for sponsoring the OVAL effort over the years which has made this work possible. The authors also wish to thank the original authors of this document Jonathan Baker, Matthew Hansbury, and Daniel Haynes of the MITRE Corporation as well as the OVAL Community for its assistance in contributing and reviewing the original document. The authors would also like to acknowledge Dave Waltermire of NIST for his contribution to the development of the original document.
This memo includes no request to IANA.
While OVAL is just a set of data models and does not directly introduce security concerns, it does provide a mechanism by which to represent endpoint posture assessment information. This information could be extremely valuable to an attacker allowing them to learn about very sensitive information including, but, not limited to: security policies, systems on the network, criticality of systems, software and hardware inventory, patch levels, user accounts and much more. To address this concern, all endpoint posture assessment information should be protected while in transit and at rest. Furthermore, it should only be shared with parties that are authorized to receive it.
Another possible security concern is due to the fact that content expressed as OVAL has the ability to impact how a security tool operates. For example, content may instruct a tool to collect certain information off a system or may be used to drive follow-up actions like remediation. As a result, it is important for security tools to ensure that they are obtaining OVAL content from a trusted source, that it has not been modified in transit, and that proper validation is performed in order to ensure it does not contain malicious data.
| [RFC2119] | Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997. |
| [OVAL-WEBSITE] | The MITRE Corporation, "The Open Vulnerability and Assessment Language", 2015. |