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) System Characteristics Model draft-rothenberg-sacm-oval-sys-char-model-00 Abstract This document specifies Version 5.11.1 of the OVAL System Characteristics Model which provides a framework for representing low-level system configuration information that can be extended to support platform-specific constructs. 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 8, 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 Cokus, et al. Expires September 8, 2016 [Page 1] Internet-Draft OVAL System Characteristics Model March 2016 the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 2. OVAL System Characteristics Model . . . . . . . . . . . . . . 3 2.1. SystemInfoType . . . . . . . . . . . . . . . . . . . . . 4 2.2. InterfacesType . . . . . . . . . . . . . . . . . . . . . 5 2.3. InterfaceType . . . . . . . . . . . . . . . . . . . . . . 5 2.4. CollectedObjectsType . . . . . . . . . . . . . . . . . . 6 2.5. ObjectType . . . . . . . . . . . . . . . . . . . . . . . 6 2.6. VariableValueType . . . . . . . . . . . . . . . . . . . . 8 2.7. ReferenceType . . . . . . . . . . . . . . . . . . . . . . 8 2.8. SystemDataType . . . . . . . . . . . . . . . . . . . . . 9 2.9. ItemType . . . . . . . . . . . . . . . . . . . . . . . . 9 2.10. EntityAttributeGroup . . . . . . . . . . . . . . . . . . 9 2.11. FlagEnumeration . . . . . . . . . . . . . . . . . . . . . 10 2.12. StatusEnumeration . . . . . . . . . . . . . . . . . . . . 11 2.13. EntityItemSimpleBaseType . . . . . . . . . . . . . . . . 12 2.14. EntityItemComplexBaseType . . . . . . . . . . . . . . . . 12 2.15. EntityItemIPAddressType . . . . . . . . . . . . . . . . . 13 2.16. EntityItemIPAddressStringType . . . . . . . . . . . . . . 13 2.17. EntityItemAnySimpleType . . . . . . . . . . . . . . . . . 14 2.18. EntityItemBinaryType . . . . . . . . . . . . . . . . . . 14 2.19. EntityItemBoolType . . . . . . . . . . . . . . . . . . . 15 2.20. EntityItemFloatType . . . . . . . . . . . . . . . . . . . 15 2.21. EntityItemIntType . . . . . . . . . . . . . . . . . . . . 16 2.22. EntityItemStringType . . . . . . . . . . . . . . . . . . 16 2.23. EntityItemRecordType . . . . . . . . . . . . . . . . . . 16 2.24. EntityItemFieldType . . . . . . . . . . . . . . . . . . . 17 2.25. EntityItemVersionType . . . . . . . . . . . . . . . . . . 18 2.26. EntityItemFileSetRevisionType . . . . . . . . . . . . . . 18 2.27. EntityItemIOSVersionType . . . . . . . . . . . . . . . . 18 2.28. EntityItemEVRStringType . . . . . . . . . . . . . . . . . 19 2.29. EntityItemDebianEVRStringType . . . . . . . . . . . . . . 19 3. OVAL System Characteristics Model Schema . . . . . . . . . . 20 4. Intellectual Property Considerations . . . . . . . . . . . . 58 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 58 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 58 7. Security Considerations . . . . . . . . . . . . . . . . . . . 58 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 59 8.1. Normative References . . . . . . . . . . . . . . . . . . 59 8.2. Informative References . . . . . . . . . . . . . . . . . 59 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 59 Cokus, et al. Expires September 8, 2016 [Page 2] Internet-Draft OVAL System Characteristics Model March 2016 1. Introduction 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 part of the OVAL contribution to the IETF SACM WG that standardizes the representation of the current machine state of a system. It is intended to serve as a starting point for the endpoint posture assessment data modeling needs of SACM specifically Posture Attributes. 1.1. Requirements Language 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. OVAL System Characteristics Model The OVAL System Characteristics Model is used to represent low-level, system settings that describe the current state of a system. The OVAL System Characteristics Model serves as a basis for extension to create platform-specific, low-level configuration information models. +------------------+---------------------+-------+------------------+ | Property | Type | Count | Description | +------------------+---------------------+-------+------------------+ | generator | oval:GeneratorType | 1 | Information | | | | | regarding the | | | | | generation of | | | | | the OVAL System | | | | | Characteristics. | | | | | The timestamp | | | | | property of the | Cokus, et al. Expires September 8, 2016 [Page 3] Internet-Draft OVAL System Characteristics Model March 2016 | | | | generator MUST | | | | | represent the | | | | | time at which | | | | | the system state | | | | | information was | | | | | collected. | | | | | | | system_info | SystemInfoType | 0..* | Information used | | | | | to identify the | | | | | system under | | | | | test. | | | | | | | collected_object | CollectedObjectsTyp | 0..1 | Contains the | | s | e | | mapping between | | | | | OVAL Objects | | | | | defined in the | | | | | OVAL Definitions | | | | | and the OVAL | | | | | Items that were | | | | | collected from | | | | | the system under | | | | | test. | | | | | | | system_data | SystemDataType | 0..1 | Contains the | | | | | OVAL Items that | | | | | were collected | | | | | from the system | | | | | under test. | | | | | | | signature | ext:Signature | 0..1 | Mechanism to | | | | | ensure the | | | | | integrity and | | | | | authenticity of | | | | | the OVAL System | | | | | Characteristics | | | | | content. | +------------------+---------------------+-------+------------------+ Table 1: oval_system_characteristics Construct 2.1. SystemInfoType The SystemInfoType defines the basic identifying information associated with the system under test. Cokus, et al. Expires September 8, 2016 [Page 4] Internet-Draft OVAL System Characteristics Model March 2016 +-------------------+--------+-------+------------------------------+ | Property | Type | Count | Description | +-------------------+--------+-------+------------------------------+ | os_name | string | 0..1 | The operating system running | | | | | on the system under test. | | | | | | | os_version | string | 1 | The version of the operating | | | | | system running on the system | | | | | under test. | | | | | | | architecture | string | 1 | The hardware architecture | | | | | type of the system under | | | | | test. | | | | | | | primary_host_name | string | 1 | The primary host name of the | | | | | system under test. | | | | | | | interfaces | any | 0..* | The network interface(s) | | | | | present on the system under | | | | | test. | | | | | | | extension_point | any | 0..* | An extension point that | | | | | allows for the inclusion of | | | | | any additional identifying | | | | | information associated with | | | | | the system under test. | +-------------------+--------+-------+------------------------------+ Table 2: SystemInfoType Construct 2.2. InterfacesType The InterfacesType provides a container for zero or more interfaces. +-----------+---------------+-------+-------------------------+ | Property | Type | Count | Description | +-----------+---------------+-------+-------------------------+ | interface | InterfaceType | 0..* | One or more interfaces. | +-----------+---------------+-------+-------------------------+ Table 3: InterfacesType Construct 2.3. InterfaceType The InterfaceType defines the information associated with a network interface on the system under test. This information may help to identify a specific system on a network. Cokus, et al. Expires September 8, 2016 [Page 5] Internet-Draft OVAL System Characteristics Model March 2016 +----------------+--------+-------+---------------------------------+ | Property | Type | Count | Description | +----------------+--------+-------+---------------------------------+ | interface_name | string | 1 | The name of the interface. | | | | | | | ip_address | string | 1 | The Internet Protocol (IP) | | | | | address of the interface. | | | | | | | mac_address | string | 1 | The Media Access Control (MAC) | | | | | address of the interface. MAC | | | | | addresses MUST be formatted | | | | | according to IEEE 802-2001 | | | | | Section 9.2.1 | | | | | [IEEE-STD-802-2001]. | +----------------+--------+-------+---------------------------------+ Table 4: InterfaceType Construct 2.4. CollectedObjectsType The CollectedObjectType is a container for one or more objects of type ObjectType that were used for data collection on the system under test. 2.5. ObjectType The ObjectType provides a mapping between an OVAL Object, defined in content based on the OVAL Definitions Model, and the OVAL Items collected on the system under test. +-------------------+----------------------+-------+----------------+ | Property | Type | Count | Description | +-------------------+----------------------+-------+----------------+ | id | oval:ObjectIDPattern | 1 | The globally | | | | | unique | | | | | identifier of | | | | | an OVAL | | | | | Object. | | | | | | | version | unsigned integer | 1 | The version of | | | | | the globally | | | | | unique OVAL | | | | | Object. | | | | | | | variable_instance | unsigned integer | 0..1 | The unique | | | | | identifier | | | | | that | | | | | differentiates | Cokus, et al. Expires September 8, 2016 [Page 6] Internet-Draft OVAL System Characteristics Model March 2016 | | | | between each | | | | | unique | | | | | instance of an | | | | | OVAL Object. | | | | | If an OVAL | | | | | Object | | | | | utilizes an | | | | | OVAL Variable, | | | | | a unique | | | | | instance of | | | | | each OVAL | | | | | Object must be | | | | | created for | | | | | each OVAL | | | | | Variable | | | | | value. Default | | | | | Value: '1' | | | | | | | comment | string | 0..1 | The | | | | | documentation | | | | | associated | | | | | with the OVAL | | | | | Object | | | | | referenced by | | | | | the id | | | | | property. | | | | | | | flag | oval:FlagEnumeration | 1 | The outcome | | | | | associated | | | | | with OVAL Item | | | | | collection. | | | | | | | message | oval:MessageType | 0..* | Any messages | | | | | that are | | | | | relayed from a | | | | | tool at run- | | | | | time. | | | | | | | variable_value | VariableValueType | 0..* | The value(s) | | | | | associated | | | | | with the | | | | | variable(s) | | | | | used by the | | | | | OVAL Object | | | | | referenced by | | | | | the id | | | | | property. | | | | | | Cokus, et al. Expires September 8, 2016 [Page 7] Internet-Draft OVAL System Characteristics Model March 2016 | reference | ReferenceType | 0..* | The | | | | | identifiers of | | | | | OVAL Items | | | | | collected by | | | | | the OVAL | | | | | Object | | | | | referenced by | | | | | the id | | | | | property. | +-------------------+----------------------+-------+----------------+ Table 5: ObjectType Construct 2.6. VariableValueType The VariableValueType identifies an OVAL Variable and value that is used by an OVAL Object during OVAL Item collection. +-------------+------------------------+-------+--------------------+ | Property | Type | Count | Description | +-------------+------------------------+-------+--------------------+ | variable_id | oval:VariableIDPattern | 1 | The unique | | | | | identifier of an | | | | | OVAL Variable. | | | | | | | value | string | 1 | A value associated | | | | | with the OVAL | | | | | Variable | | | | | identified by the | | | | | variable_id | | | | | property. | +-------------+------------------------+-------+--------------------+ Table 6: VariableValueType Construct 2.7. ReferenceType The ReferenceType identifies an OVAL Item that was collected during OVAL Item collection. +----------+--------------------+-------+---------------------------+ | Property | Type | Count | Description | +----------+--------------------+-------+---------------------------+ | item_ref | oval:ItemIDPattern | 1 | The unique identifier of | | | | | an OVAL Item. | +----------+--------------------+-------+---------------------------+ Table 7: ReferenceType Construct Cokus, et al. Expires September 8, 2016 [Page 8] Internet-Draft OVAL System Characteristics Model March 2016 2.8. SystemDataType The SystemDataType provides a container for all of the OVAL Items that were collected on the system under test. 2.9. ItemType The ItemType is the abstract OVAL Item that defines the common properties associated with all OVAL Items defined in the OVAL System Characteristics OVAL Component Models. +----------+--------------------+-------+---------------------------+ | Property | Type | Count | Description | +----------+--------------------+-------+---------------------------+ | id | oval:ItemIDPattern | 1 | The unique identifier of | | | | | an OVAL Item. The id | | | | | property is unique within | | | | | a given instantiation of | | | | | the OVAL System | | | | | Characteristics Model. | | | | | | | status | StatusEnumeration | 0..1 | The status property of an | | | | | OVAL Item conveys the | | | | | outcome of the system | | | | | data collection effort. | | | | | Default Value: 'exists' | | | | | | | message | MessageType | 0..50 | Any messages that are | | | | | relayed from a tool at | | | | | run-time during the | | | | | collection of an OVAL | | | | | Item. | +----------+--------------------+-------+---------------------------+ Table 8: GeneratorType ItemType 2.10. EntityAttributeGroup The EntityAttributeGroup defines the properties that are common to all OVAL Item Entities in the OVAL Language. Cokus, et al. Expires September 8, 2016 [Page 9] Internet-Draft OVAL System Characteristics Model March 2016 +----------+--------------------------+-------+---------------------+ | Property | Type | Count | Description | +----------+--------------------------+-------+---------------------+ | datatype | oval:DatatypeEnumeration | 0..1 | The datatype for | | | | | the entity. Default | | | | | Value: 'string' | | | | | | | mask | boolean | 0..1 | Tells the data | | | | | collection that | | | | | this entity | | | | | contains sensitive | | | | | data. Data marked | | | | | with mask='true' | | | | | should be used only | | | | | in the evaluation, | | | | | and not be included | | | | | in the results. | | | | | Note that when the | | | | | mask property is | | | | | set to 'true', all | | | | | child field | | | | | elements must be | | | | | masked regardless | | | | | of the child | | | | | field's mask | | | | | attribute value. | | | | | Default Value: | | | | | 'false' | | | | | | | status | StatusEnumeration | 0..1 | The status of the | | | | | collection for an | | | | | OVAL Item Entity. | | | | | Default Value: | | | | | 'exists' | +----------+--------------------------+-------+---------------------+ Table 9: EntityAttributeGroup Construct 2.11. FlagEnumeration The FlagEnumeration defines the acceptable outcomes associated with the collection of OVAL Items for a specified OVAL Object. Cokus, et al. Expires September 8, 2016 [Page 10] Internet-Draft OVAL System Characteristics Model March 2016 +------------+------------------------------------------------------+ | Value | Description | +------------+------------------------------------------------------+ | error | This value indicates that an error prevented the | | | determination of the existence of OVAL Items on the | | | system. | | | | | complete | This value indicates that every matching OVAL Item | | | on the system has been identified and represented in | | | the OVAL System Characteristics. It can be assumed | | | that no additional matching OVAL Items exist on the | | | system. | | | | | incomplete | This value indicates that matching OVAL Items exist | | | on the system, however, only a subset of those | | | matching OVAL Items have been identified and | | | represented in the OVAL System Characteristics. It | | | cannot be assumed that no additional matching OVAL | | | Items exist on the system. | | | | | does not | This value indicates that no matching OVAL Items | | exist | were found on the system. | | | | | not | This value indicates that no attempt was made to | | collected | collect OVAL Items on the system. | | | | | not | This value indicates that the specified OVAL Object | | applicable | is not applicable to the system under test. | +------------+------------------------------------------------------+ Table 10: FlagEnumeration Construct 2.12. StatusEnumeration The StatusEnumeration defines the acceptable status values associated with the collection of an OVAL Item or the properties of an OVAL Item. Cokus, et al. Expires September 8, 2016 [Page 11] Internet-Draft OVAL System Characteristics Model March 2016 +-----------+-------------------------------------------------------+ | Value | Description | +-----------+-------------------------------------------------------+ | error | This value indicates that there was an error | | | collecting an OVAL Item or a property of an OVAL | | | Item. | | | | | exists | This value indicates that an OVAL Item, or a property | | | of an OVAL Item, exists on the system and was | | | collected. | | | | | does not | This value indicates that an OVAL Item, or a property | | exist | of an OVAL Item, does not exist on the system. | | | | | not | This value indicates that no attempt was made to | | collected | collect an OVAL Item or a property of an OVAL Item. | +-----------+-------------------------------------------------------+ Table 11: StatusEnumeration Construct 2.13. EntityItemSimpleBaseType The EntityItemSimpleBaseType is an abstract type that defines a base type for all simple OVAL Item Entities. +------------+----------------------+-------+-----------------------+ | Property | Type | Count | Description | +------------+----------------------+-------+-----------------------+ | attributes | EntityAttributeGroup | 1 | The standard | | | | | attributes available | | | | | to all entities. | | | | | | | value | string | 0..1 | The value of the | | | | | entity. An empty | | | | | string value SHOULD | | | | | be used when a status | | | | | other than 'exists' | | | | | is specified. | +------------+----------------------+-------+-----------------------+ Table 12: EntityItemSimpleBaseType Construct 2.14. EntityItemComplexBaseType The EntityItemComplexBaseType is an abstract type that defines a base type for all complex OVAL Item Entities. Cokus, et al. Expires September 8, 2016 [Page 12] Internet-Draft OVAL System Characteristics Model March 2016 +------------+----------------------+-------+-----------------------+ | Property | Type | Count | Description | +------------+----------------------+-------+-----------------------+ | attributes | EntityAttributeGroup | 1 | The standard | | | | | attributes available | | | | | to all entities. | +------------+----------------------+-------+-----------------------+ Table 13: EntityItemComplexBaseType Construct 2.15. EntityItemIPAddressType The EntityItemIPAddressType extends the EntityItemSimpleBaseType and describes an IPv4 or IPv6 IP address or prefix. +----------+-----------------+-------+------------------+ | Property | Type | Count | Description | | | | | | +----------+-----------------+-------+------------------+ | datatype | oval: | 1 | Possible | | | SimpleDatatype | | values: | | | Enumeration | | | | | | | o 'ipv4_address' | | | | | o 'ipv6_address' | | | | | | | | | | Also allows an | | | | | empty string | | | | | value. | +----------+-----------------+-------+------------------+ Figure 1: EntityItemIPAddressType Construct 2.16. EntityItemIPAddressStringType The EntityItemIPAddressStringType extends the EntityItemSimpleBaseType and describes an IPv4 or IPv6 IP address or prefix or a string representation of the address. Cokus, et al. Expires September 8, 2016 [Page 13] Internet-Draft OVAL System Characteristics Model March 2016 +----------+-----------------+-------+------------------+ | Property | Type | Count | Description | | | | | | +----------+-----------------+-------+------------------+ | datatype | oval: | 1 | Possible | | | SimpleDatatype | | values: | | | Enumeration | | | | | | | o 'ipv4_address' | | | | | o 'ipv6_address' | | | | | o 'string' | | | | | | | | | | Also allows an | | | | | empty string | | | | | value. | +----------+-----------------+-------+------------------+ Figure 2: EntityItemIPAddressStringType Construct 2.17. EntityItemAnySimpleType The EntityItemAnySimpleType extends the EntityItemSimpleBaseType and describes any simple data. +----------+--------------------------------+-------+---------------+ | Property | Type | Count | Description | +----------+--------------------------------+-------+---------------+ | datatype | oval:SimpleDatatypeEnumeration | 1 | Any simple | | | | | datatype. | | | | | Also allows | | | | | an empty | | | | | string value. | +----------+--------------------------------+-------+---------------+ Table 14: EntityItemAnySimpleType Construct 2.18. EntityItemBinaryType The EntityItemBinaryType extends the EntityItemSimpleBaseType and describes any simple binary data. Cokus, et al. Expires September 8, 2016 [Page 14] Internet-Draft OVAL System Characteristics Model March 2016 +----------+--------------------------------+-------+---------------+ | Property | Type | Count | Description | +----------+--------------------------------+-------+---------------+ | datatype | oval:SimpleDatatypeEnumeration | 1 | This value is | | | | | fixed as | | | | | 'binary'. | | | | | Also allows | | | | | an empty | | | | | string value. | +----------+--------------------------------+-------+---------------+ Table 15: EntityItemBinaryType Construct 2.19. EntityItemBoolType The EntityItemBoolType extends the EntityItemSimpleBaseType and describes any simple boolean data. +----------+--------------------------------+-------+---------------+ | Property | Type | Count | Description | +----------+--------------------------------+-------+---------------+ | datatype | oval:SimpleDatatypeEnumeration | 1 | This value is | | | | | fixed as | | | | | 'boolean'. | | | | | Also allows | | | | | an empty | | | | | string value. | +----------+--------------------------------+-------+---------------+ Table 16: EntityItemBoolType Construct 2.20. EntityItemFloatType The EntityItemFloatType extends the EntityItemSimpleBaseType and describes any simple float data. +----------+--------------------------------+-------+---------------+ | Property | Type | Count | Description | +----------+--------------------------------+-------+---------------+ | datatype | oval:SimpleDatatypeEnumeration | 1 | This value is | | | | | fixed as | | | | | 'float'. Also | | | | | allows an | | | | | empty string | | | | | value. | +----------+--------------------------------+-------+---------------+ Table 17: EntityItemFloatType Construct Cokus, et al. Expires September 8, 2016 [Page 15] Internet-Draft OVAL System Characteristics Model March 2016 2.21. EntityItemIntType The EntityItemIntType extends the EntityItemSimpleBaseType and describes any simple integer data. +----------+--------------------------------+-------+---------------+ | Property | Type | Count | Description | +----------+--------------------------------+-------+---------------+ | datatype | oval:SimpleDatatypeEnumeration | 1 | This value is | | | | | fixed as | | | | | 'int'. Also | | | | | allows an | | | | | empty string | | | | | value. | +----------+--------------------------------+-------+---------------+ Table 18: EntityItemIntType Construct 2.22. EntityItemStringType The EntityItemStringType extends the EntityItemSimpleBaseType and describes any simple string data. +----------+--------------------------------+-------+---------------+ | Property | Type | Count | Description | +----------+--------------------------------+-------+---------------+ | datatype | oval:SimpleDatatypeEnumeration | 0..1 | This value is | | | | | fixed as | | | | | 'string'. | +----------+--------------------------------+-------+---------------+ Table 19: EntityItemStringType Construct 2.23. EntityItemRecordType The EntityItemRecordType extends the EntityItemComplexBaseType and allows assertions to be made on entities with uniquely named fields. It is intended to be used to assess the results of things such as SQL statements and similar data. Cokus, et al. Expires September 8, 2016 [Page 16] Internet-Draft OVAL System Characteristics Model March 2016 +----------+---------------------------------+-------+--------------+ | Property | Type | Count | Description | +----------+---------------------------------+-------+--------------+ | datatype | oval:ComplexDatatypeEnumeration | 0..1 | This value | | | | | is fixed as | | | | | 'record'. | | | | | | | field | EntityItemFieldType | 0..* | Defines the | | | | | name of the | | | | | field whose | | | | | value will | | | | | be assessed. | +----------+---------------------------------+-------+--------------+ Table 20: EntityItemRecordType Construct 2.24. EntityItemFieldType The EntityItemFieldType defines an entity type that captures the details of a single field for a record. +------------+----------------------+-------+-----------------------+ | Property | Type | Count | Description | +------------+----------------------+-------+-----------------------+ | attributes | EntityAttributeGroup | 1 | The standard | | | | | attributes available | | | | | to all entities. | | | | | | | name | string | 1 | The name of the | | | | | field. Names MUST be | | | | | all lower case | | | | | characters in the | | | | | range of a-z. | | | | | | | value | string | 0..1 | The value of the | | | | | field. An empty | | | | | string value SHOULD | | | | | be used when a status | | | | | other than 'exists' | | | | | is specified. | +------------+----------------------+-------+-----------------------+ Table 21: EntityItemFieldType Construct Cokus, et al. Expires September 8, 2016 [Page 17] Internet-Draft OVAL System Characteristics Model March 2016 2.25. EntityItemVersionType The EntityItemVersionType extends the EntityItemSimpleBaseType and describes a version string data. +----------+--------------------------------+-------+---------------+ | Property | Type | Count | Description | +----------+--------------------------------+-------+---------------+ | datatype | oval:SimpleDatatypeEnumeration | 1 | This value is | | | | | fixed as | | | | | 'version'. | | | | | Also allows | | | | | an empty | | | | | string value. | +----------+--------------------------------+-------+---------------+ Table 22: EntityItemVersionType Construct 2.26. EntityItemFileSetRevisionType The EntityItemFileSetRevisionType extends the EntityItemSimpleBaseType and describes a file set revision string data. +---------+----------------------------+-------+--------------------+ | Propert | Type | Count | Description | | y | | | | +---------+----------------------------+-------+--------------------+ | datatyp | oval:SimpleDatatypeEnumera | 1 | This value is | | e | tion | | fixed as 'fileset_ | | | | | revision'. Also | | | | | allows an empty | | | | | string value. | +---------+----------------------------+-------+--------------------+ Table 23: EntityItemFileSetRevisionType Construct 2.27. EntityItemIOSVersionType The EntityItemIOSVersionType extends the EntityItemSimpleBaseType and describes a Cisco IOS version string data. Cokus, et al. Expires September 8, 2016 [Page 18] Internet-Draft OVAL System Characteristics Model March 2016 +----------+-----------------+-------+------------------+ | Property | Type | Count | Description | | | | | | +----------+-----------------+-------+------------------+ | datatype | oval: | 1 | Possible | | | SimpleDatatype | | values: | | | Enumeration | | | | | | | o 'ios_version' | | | | | o 'string' | | | | | | | | | | The string | | | | | type is an | | | | | option in | | | | | order to allow | | | | | use of regular | | | | | expressions. | +----------+-----------------+-------+------------------+ Figure 3: EntityItemIOSVersionType Construct 2.28. EntityItemEVRStringType The EntityItemEVRStringType extends the EntityItemSimpleBaseType and describes an EPOCH:VERSION-RELEASE string data. +----------+--------------------------------+-------+---------------+ | Property | Type | Count | Description | +----------+--------------------------------+-------+---------------+ | datatype | oval:SimpleDatatypeEnumeration | 1 | This value is | | | | | fixed as | | | | | 'evr_string'. | | | | | Also allows | | | | | an empty | | | | | string value. | +----------+--------------------------------+-------+---------------+ Table 24: EntityItemEVRStringType Construct 2.29. EntityItemDebianEVRStringType The EntityItemDebianEVRStringType extends the EntityItemSimpleBaseType and describes an EPOCH:UPSTREAM_VERSION- DEBIAN_REVISION string data for a Debian package. Cokus, et al. Expires September 8, 2016 [Page 19] Internet-Draft OVAL System Characteristics Model March 2016 +---------+----------------------------+-------+--------------------+ | Propert | Type | Count | Description | | y | | | | +---------+----------------------------+-------+--------------------+ | datatyp | oval:SimpleDatatypeEnumera | 1 | This value is | | e | tion | | fixed as 'debian_e | | | | | vr_string'. Also | | | | | allows an empty | | | | | string value. | +---------+----------------------------+-------+--------------------+ Table 25: EntityItemDebianEVRStringType Construct 3. OVAL System Characteristics Model Schema The XML Schema that implements this OVAL System Characteristics Model can be found below. The following is a description of the elements, types, and attributes that compose the core schema for encoding Open Vulnerability and Assessment Language (OVAL) System Characteristics. The Core System Cokus, et al. Expires September 8, 2016 [Page 20] Internet-Draft OVAL System Characteristics Model March 2016 Characteristics Schema defines all operating system independent objects. These objects are extended and enhanced by individual family schemas, which are described in separate documents. Each of the elements, types, and attributes that make up the Core System Characteristics 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. Core System Characteristics 5.11.1 4/22/2015 09:00:00 AM Copyright (C) 2010 United States Government. All Rights Reserved. The system_characteristics element is the root of an OVAL System Characteristics Document, and must occur exactly once. Its purpose is to bind together the four major sections of a system characteristics file - generator, system_info, collected_objects, and system_data - which are the Cokus, et al. Expires September 8, 2016 [Page 21] Internet-Draft OVAL System Characteristics Model March 2016 children of the oval_system_characteristics element. The generator section must be present and provides information about when the system characteristics file was compiled and under what version. The required system_info element is used to record information about the system being described. The optional collected_objects section is used to associated the ids of the OVAL Objects collected with the system characteristics items that have been defined. The collected_objects section provides a listing of all the objects used to generate this system Cokus, et al. Expires September 8, 2016 [Page 22] Internet-Draft OVAL System Characteristics Model March 2016 characteristics file. The optional system_data section defines the specific characteristics that have been collected from the system. 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/. Enforce uniqueness amongst the individual object ids used in the collected object section. Cokus, et al. Expires September 8, 2016 [Page 23] Internet-Draft OVAL System Characteristics Model March 2016 Enforce uniqueness amongst the individual item ids. Require that each item reference refers to a valid item id. The SystemInfoType Cokus, et al. Expires September 8, 2016 [Page 24] Internet-Draft OVAL System Characteristics Model March 2016 complex type specifies general information about the system that data was collected from, including information that can be used to identify the system. See the description of the InterfacesType complex type for more information. Note that the high level interfaces is required due to the inclusion of the xsd:any tag that follows it. The interfaces tag can be empty if no single interface is present. Additional system information is also allowed although it is not part of the official OVAL Schema. Individual organizations can place system information that they feel is important and these will be skipped during the validation. All OVAL really cares about is that the required system information items are there. The required os_name elements describes the operating system of the machine the data was collected on. The required os_version elements describe the operating system version of the machine the data was collected on. Cokus, et al. Expires September 8, 2016 [Page 25] Internet-Draft OVAL System Characteristics Model March 2016 The required architecture element describes the hardware architecture type of the system data was collected on. The required primary_host_name element is the primary host name of the machine the data was collected on. The required interfaces element outlines the network interfaces that exist on the system. The Asset Identification specification (http://scap.nist.gov/specifications/ai/) provides a standardized way of reporting asset information across different Cokus, et al. Expires September 8, 2016 [Page 26] Internet-Draft OVAL System Characteristics Model March 2016 organizations. The information contained within an AI computing-device element is similar to the information collected by OVAL's SystemInfoType. To support greater interoperability, an ai:computing-device element describing the system that data was collected from may appear at this point in an OVAL System Characteristics document. The InterfacesType complex type is a container for zero or more interface elements. Each interface element is used to describe an existing network interface on the system. Please refer to the description of the InterfaceType for more information. Cokus, et al. Expires September 8, 2016 [Page 27] Internet-Draft OVAL System Characteristics Model March 2016 The InterfaceType complex type is used to describe an existing network interface on the system. This information can help identify a specific system on a given network. The required interface_name element is the name of the interface The required ip_address element holds the IP address for the interface. Note that the IP address can be IPv4 or IPv6. The required mac_address element holds the MAC address for the interface. MAC addresses should be formatted according to the IEEE 802-2001 standard which states that a MAC address is a sequence of six octet values, separated by hyphens, where each octet is represented by two hexadecimal digits. Cokus, et al. Expires September 8, 2016 [Page 28] Internet-Draft OVAL System Characteristics Model March 2016 Uppercase letters should also be used to represent the hexadecimal digits A through F. The CollectedObjectsType complex type states all the objects that have been collected by the system characteristics file. The details of each object are defined by the global OVAL object that is identified by the id. The ObjectType complex type provides a reference between items collected and a related global OVAL Object. If an OVAL Object does not exist on the system, then an object element is still provided but with the flag attribute set to 'does not exist'. For details on how to handle items, when an OVAL Object does not exist on the system, please see the ItemType documentation. This shows that the object was Cokus, et al. Expires September 8, 2016 [Page 29] Internet-Draft OVAL System Characteristics Model March 2016 looked for but not found on the system. If no object element is written in this case, users of the system characteristics file will not know whether the object was not found or no attempt was made to collect it. The required id attribute is the id of the global OVAL Object. The required version attribute is the specific version of the global OVAL Object that was used by the data collection engine. The version is necessary so that analysis using a system characteristics file knows exactly what was collected. The optional variable_instance identifier is a unique id that differentiates each unique instance of an object. Capabilities that use OVAL may reference the same definition multiple times and provide different variable values each time the definition is referenced. This will result in multiple instances of an object being included in the OVAL System Characteristics file (definitions that do not use variables can only have one unique instance). The inclusion of this unique instance identifier allows the OVAL Results document to associate the correct objects and items for each combination of supplied values. The optional comment attribute provides a short description of the object. The required flag attribute holds information regarding the outcome of the data collection. For example, if there Cokus, et al. Expires September 8, 2016 [Page 30] Internet-Draft OVAL System Characteristics Model March 2016 was an error looking for items that match the object specification, then the flag would be 'error'. Please refer to the description of FlagEnumeration for details about the different flag values. The optional message element holds an error message or some other string that the data collection engine wishes to pass along. The optional variable_value elements define the actual value(s) used during data collection of any variable referenced by the object (as well as any object referenced via a set element). An OVAL Object that includes a variable maybe have a different unique set of matching items depending on the value assigned to the variable. A tool that is given an OVAL System Characteristics file in order to analyze an OVAL Definition needs to be able to determine the Cokus, et al. Expires September 8, 2016 [Page 31] Internet-Draft OVAL System Characteristics Model March 2016 exact instance of an object to use based on the variable values supplied. If a variable represents a collection of values, then multiple variable_value elements would exist with the same variable_id attribute. The optional reference element links the collected item found by the data collection engine and the global OVAL Object. A global OVAL Object my have multiple matching items on a system. For example a global file object that is a pattern match might match 10 different files on a specific system. In this case, there would be 10 reference elements, one for each of the files found on the system. The VariableValueType complex type holds the value to a variable used during the collection of an object. The required variable_id attribute is the unique id of the variable being identified. The ReferenceType complex type specifies an item in the system characteristics file. This reference is used to link global OVAL Objects to specific items. The SystemDataType complex type is a container for one or more item elements. Each item defines a specific piece of data on the Cokus, et al. Expires September 8, 2016 [Page 33] Internet-Draft OVAL System Characteristics Model March 2016 system. The abstract item element holds information about a specific item on a system. An item might be a file, a rpm, a process, etc. This element is extended by the different component schemas through substitution groups. Each item represents a unique instance of an object as specified by an OVAL Object. For example, a single file or a single user. Each item may be referenced by more than one object in the collected object section. Please refer to the description of ItemType for more details about the information stored in items. The ItemType complex type specifies an optional message element that is used to pass things like error messages during data collection to a tool that will utilize the information. The required id attribute is a unique (to the file) identifier that allows the specific item to be referenced. The required status attribute holds information regarding the success of the data Cokus, et al. Expires September 8, 2016 [Page 34] Internet-Draft OVAL System Characteristics Model March 2016 collection. For example, if an item exists on the system then the status would reflect this with a value of 'exists'. If there was an error collecting any information about an item that is known to exist, then the status would be 'error'. An error specific to a particular entity should be addressed at the entity level and not the item level. When creating items, any entities that can successfully be collected should be reported. In some cases, when an item for a specified object does not exist, it may be beneficial to report a partial match of an item showing what entities did exist and what entities did not exist for debugging purposes. This is especially true when considering items that are collected by objects with hierarchical object entities. An example of such a case is when a file_object has a path entity equal to 'C:\' and a filename entity equal to 'test.txt' where 'test.txt' does not exist in the 'C:\' directory. This would result in the creation of a partially matching file_item with a status of 'does not exist' where the path entity equals 'C:\' and the filename entity equals 'test.txt' with a status of 'does not exist'. By showing the partial match, someone reading a system-characteristics document can quickly see that a matching file_item did not exist because the specified filename did not exist and not that the specified path did not exist. Again, please note that the implementation of partial matches, when an item for a specified object does not exist, Cokus, et al. Expires September 8, 2016 [Page 35] Internet-Draft OVAL System Characteristics Model March 2016 is completely optional. The FlagEnumeration simple type defines the valid flags associated with a collected object. These flags are meant to provide information about how the specified object was handled by the data collector. In order to evaluate an OVAL Definition, information about the defined objects needs to be available. The flags help detail the outcome of attempting to collect information related to these objects.. Below is a table that outlines how each Cokus, et al. Expires September 8, 2016 [Page 36] Internet-Draft OVAL System Characteristics Model March 2016 FlagEnumeration value effects evaluation of a given test. Note that this is related to the existence of a unique set of items identified by an object and not each item's compliance with a state. The left column identifies the FlagEnumeration value in question. The right column specifies the ResultEnumeration value that should be used when evaluating the collected object. || flag value || test result is || -----------------||---------------------------- error || error complete || (test result depends on incomplete || check_existence and does not exist || check attributes) not collected || unknown not applicable || not applicable -----------------||----------------------------- A flag of 'error' indicates that there was an error trying to identify items on the system that match the specified object declaration. This flag is not meant to be used when there was an error retrieving a specific entity, but rather when it could not be determined if an item exists or not. Any error in retrieving a specific entity should be Cokus, et al. Expires September 8, 2016 [Page 37] Internet-Draft OVAL System Characteristics Model March 2016 represented by setting the status of that specific entity to 'error'. A flag of 'complete' indicates that every matching item on the system has been identified and is represented in the system characteristics file. It can be assumed that no additional matching items exist on the system. A flag of 'incomplete' indicates that a matching item exists on the system, but only some of the matching items have been identified and are represented in the system characteristics file. It is unknown if additional matching items also exist. Note that with a flag of 'incomplete', each item that has been identified matches the object declaration, but additional items might also exist on the system. A flag of 'does not exist' indicates Cokus, et al. Expires September 8, 2016 [Page 38] Internet-Draft OVAL System Characteristics Model March 2016 that the underlying structure is installed on the system but no matching item was found. For example, the Windows metabase is installed but there were no items that matched the metabase_object. In this example, if the metabase itself was not installed, then the flag would have been 'not applicable'. A flag of 'not collected' indicates that no attempt was made to collect items on the system. An object with this flag will produce an 'unknown' result during analysis since it is unknown if matching items exists on the system or not. This is different from an 'error' flag because an 'error' flag indicates that an attempt was made to collect items on system whereas a 'not collected' flag indicates that an attempt was not made to collect items on the system. A flag of 'not applicable' indicates that the specified object is not applicable to the Cokus, et al. Expires September 8, 2016 [Page 39] Internet-Draft OVAL System Characteristics Model March 2016 system being characterized. This could be because the data repository is not installed or that the object structure is for a different flavor of systems. An example would be trying to collect objects related to a Red Hat system off of a Windows system. Another example would be trying to collect an rpminfo_object on a Linux system if the rpm packaging system is not installed. If the rpm packaging system is installed and the specified rpminfo_object could not be found, then the flag would be 'does not exist'. The StatusEnumeration simple type defines the valid status messages associated with collection of specific information associated with an item. A status of 'error' says that there was an error collecting information associated with an item as a whole or a specific entity. An item would have a status of 'error' if a problem Cokus, et al. Expires September 8, 2016 [Page 40] Internet-Draft OVAL System Characteristics Model March 2016 occurred that prevented the item from being collected. For example, a file_item would have a status of 'error' if a handle to the file could not be opened because the handle was already in use by another program. Also, if an item has entities with a status of 'error' and entities with a status of 'exists', the status of 'error' must not be propagated up to the item level as the item may still be usable. A status of 'exists' says that the item or specific piece of information exists on the system and has been collected. A status of 'does not exist' says that the item or specific piece of information does not exist and therefore has not been collected. This status assumes that an attempt was made to collect the information, but the information just does not exist. This can happen when a certain entity is only pertinent to particular instances or if the information for Cokus, et al. Expires September 8, 2016 [Page 41] Internet-Draft OVAL System Characteristics Model March 2016 that entity is not set. A status of 'not collected' says that no attempt was made to collect the item or specific piece of information so it is unknown what the value is and if it even exists. The EntityAttributeGroup is a collection of attributes that are common to all entities. This group defines these attributes and their default values. Individual entities may limit allowed values for these attributes, but all entities will support these attributes. Warning: item - a Cokus, et al. Expires September 8, 2016 [Page 42] Internet-Draft OVAL System Characteristics Model March 2016 value for the entity should only be supplied if the status attribute is 'exists' - The datatype for the entity is 'int' but the value is not an integer. The optional datatype attribute determines the type of data expected (the default datatype is 'string'). Note that the datatype attribute simply defines the type of data as found on the system, it is not used during evaluation. An OVAL Definition defines how the data should be interpreted during analysis. If the definition states a datatype that is different than what the system characteristics presents, then a type cast must be made. The optional mask attribute is used to identify values that have been Cokus, et al. Expires September 8, 2016 [Page 44] Internet-Draft OVAL System Characteristics Model March 2016 hidden for sensitivity concerns. This is used by the Result document which uses the System Characteristics schema to format the information found on a specific system. When the mask attribute is set to 'true' on an OVAL Entity or an OVAL Field, the corresponding collected value of that OVAL Entity or OVAL Field MUST NOT be present in the "results" section of the OVAL Results document; the "oval_definitions" section must not be altered and must be an exact copy of the definitions evaluated. Values MUST NOT be masked in OVAL System Characteristics documents that are not contained within an OVAL Results document. It is possible for masking conflicts to occur where one entity has mask set to true and another entity has mask set to false. A conflict will occur when the mask attribute is set differently on an OVAL Object and matching OVAL State or when more than one OVAL Objects identify the same OVAL Item(s). When such a conflict occurs the result is always to mask the entity. The optional status attribute holds information regarding the success of the data collection. For example, if Cokus, et al. Expires September 8, 2016 [Page 45] Internet-Draft OVAL System Characteristics Model March 2016 there was an error collecting a particular piece of data, then the status would be 'error'. The EntityItemSimpleBaseType complex type is an abstract type that serves as the base type for all simple item entities. The EntityItemComplexBaseType complex type is an abstract type that serves as the base type for all complex item entities. The Cokus, et al. Expires September 8, 2016 [Page 46] Internet-Draft OVAL System Characteristics Model March 2016 EntityItemIPAddressType type is extended by the entities of an individual item. This type provides uniformity to each entity by including the attributes found in the EntityItemSimpleBaseType. This specific type describes any IPv4/IPv6 address or address prefix. The EntityItemIPAddressStringType type is extended by the entities of an individual item. This type provides uniformity to each entity by including the attributes found in the EntityItemSimpleBaseType. This specific type describes any IPv4/IPv6 address, address prefix, or its string representation. Cokus, et al. Expires September 8, 2016 [Page 47] Internet-Draft OVAL System Characteristics Model March 2016 The EntityItemAnySimpleType type is extended by the entities of an individual item. This type provides uniformity to each entity by including the attributes found in the EntityItemSimpleBaseType. This specific type describes any simple data. Cokus, et al. Expires September 8, 2016 [Page 48] Internet-Draft OVAL System Characteristics Model March 2016 The EntityItemBinaryType type is extended by the entities of an individual item. This type provides uniformity to each entity by including the attributes found in the EntityItemSimpleBaseType. This specific type describes simple binary data. The empty string is also allowed for cases where there was an error in the data collection of an entity and a status needs to be reported. The EntityItemBoolType type is extended by the entities of an individual item. This type provides uniformity to each entity by including the attributes found in the EntityItemSimpleBaseType. This specific type describes simple boolean data. The empty string is also allowed for cases Cokus, et al. Expires September 8, 2016 [Page 49] Internet-Draft OVAL System Characteristics Model March 2016 where there was an error in the data collection of an entity and a status needs to be reported. The EntityItemFloatType type is extended by the entities of an individual item. This type provides uniformity to each entity by including the attributes found in the EntityItemSimpleBaseType. This specific type describes simple float data. The empty string is also allowed for cases where there was an error in the data collection of an entity and a status needs to be reported. The EntityItemIntType type is extended by the entities of an individual item. This type provides uniformity to each entity by including the attributes found in the EntityItemSimpleBaseType. This specific type describes simple integer data. The empty string is also allowed for cases where there was an error in the data collection of an entity and a status needs to be reported. The EntityItemStringType type is extended by the entities of an individual item. This type provides uniformity to each entity by including the attributes found in the EntityItemSimpleBaseType. This specific type describes simple string data. Cokus, et al. Expires September 8, 2016 [Page 51] Internet-Draft OVAL System Characteristics Model March 2016 The EntityItemRecordType defines an entity that consists of a number of named fields. This structure is used for representing a record from a database query and other similar structures where multiple related fields must be collected at once. Note that for all entities of this type, the only allowed datatype is 'record'. Note the datatype attribute must be set to 'record'. Note that when the mask attribute is set to 'true', all child field elements must be masked regardless of the child field's mask attribute Cokus, et al. Expires September 8, 2016 [Page 52] Internet-Draft OVAL System Characteristics Model March 2016 value. The EntityItemFieldType defines an element with simple content that represents a named field in a record that may contain any number of named fields. The EntityItemFieldType is much like all other entities with one significant difference, the EntityItemFieldType has a name attribute. The required name attribute specifies a name for the field. Field names are lowercase and may occur more than once to allow for a field to have multiple values. Note that when the mask attribute is set to 'true' on a field's parent element the field must be masked regardless of the field's mask attribute value. A string restricted to Cokus, et al. Expires September 8, 2016 [Page 53] Internet-Draft OVAL System Characteristics Model March 2016 disallow upper case characters. The EntityItemVersionType type is extended by the entities of an individual item. This type provides uniformity to each entity by including the attributes found in the EntityItemSimpleBaseType. This specific type describes version data. The EntityItemFilesetRevisionType type Cokus, et al. Expires September 8, 2016 [Page 54] Internet-Draft OVAL System Characteristics Model March 2016 is extended by the entities of an individual item. This type provides uniformity to each entity by including the attributes found in the EntityItemSimpleBaseType. This specific type represents the version string related to filesets in HP-UX. The EntityItemIOSVersionType type is extended by the entities of an individual item. This type provides uniformity to each entity by including the attributes found in the EntityItemSimpleBaseType. This specific type represents the version string for IOS. Cokus, et al. Expires September 8, 2016 [Page 55] Internet-Draft OVAL System Characteristics Model March 2016 The EntityItemEVRStringType type is extended by the entities of an individual item. This type provides uniformity to each entity by including the attributes found in the EntityItemSimpleBaseType. This type represents the epoch, version, and release fields, for an RPM package, as a single version string. It has the form "EPOCH:VERSION-RELEASE". Note that a null epoch (or '(none)' as returned by rpm) is equivalent to '0' and would hence have the form 0:VERSION-RELEASE. Comparisons involving this datatype should follow the algorithm of librpm's rpmvercmp() function. The EntityItemDebianEVRStringType type Cokus, et al. Expires September 8, 2016 [Page 56] Internet-Draft OVAL System Characteristics Model March 2016 is extended by the entities of an individual item. This type provides uniformity to each entity by including the attributes found in the EntityItemSimpleBaseType. This type represents the epoch, upstream_version, and debian_revision fields, for a Debian package, as a single version string. It has the form "EPOCH:UPSTREAM_VERSION-DEBIAN_REVISION". Note that a null epoch (or '(none)' as returned by dpkg) is equivalent to '0' and would hence have the form 0:UPSTREAM_VERSION-DEBIAN_REVISION. Comparisons involving this datatype should follow the algorithm outlined in Chapter 5 of the "Debian Policy Manual" (https://www.debian.org/doc/debian-policy/ ch-controlfields.html#s-f-Version). An implementation of this is the cmpversions() function in dpkg's enquiry.c. Cokus, et al. Expires September 8, 2016 [Page 57] Internet-Draft OVAL System Characteristics Model March 2016 4. Intellectual Property Considerations 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. 5. Acknowledgements 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. 6. IANA Considerations This memo includes no request to IANA. 7. Security Considerations 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 Cokus, et al. Expires September 8, 2016 [Page 58] Internet-Draft OVAL System Characteristics Model March 2016 validation is performed in order to ensure it does not contain malicious data. 8. References 8.1. Normative References [IEEE-STD-802-2001] IEEE, "IEEE Std 802-2001 - IEEE Standard for Local and Metropolitan Area Networks: Overview and Architecture", 1999, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . 8.2. Informative References [OVAL-WEBSITE] The MITRE Corporation, "The Open Vulnerability and Assessment Language", 2015, . Authors' Addresses Michael Cokus The MITRE Corporation 903 Enterprise Parkway, Suite 200 Hampton, VA 23666 USA Email: msc@mitre.org Daniel Haynes The MITRE Corporation 202 Burlington Road Bedford, MA 01730 USA Email: dhaynes@mitre.org Cokus, et al. Expires September 8, 2016 [Page 59] Internet-Draft OVAL System Characteristics Model March 2016 David Rothenberg The MITRE Corporation 202 Burlington Road Bedford, MA 01730 USA Email: drothenberg@mitre.org Juan Gonzalez Department of Homeland Security 245 Murray Lane Washington, DC 20548 USA Email: juan.gonzalez@dhs.gov Cokus, et al. Expires September 8, 2016 [Page 60]