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This section describes the modeling of security control information in
an OSCAL-based FedRAMP SSP. To ensure consistent processing, FedRAMP
imposes specific requirements on the use of OSCAL for control implementation information.
The modeling of controls is addressed in the following sections as
follows:
All control definition information is imported from the appropriate
FedRAMP baseline (OSCAL profile). This includes the original NIST control definition and parameter labels as well as any FedRAMP control guidance and parameter constraints.
Interpreting and presenting profile content is out of the scope of this
documentation. Please refer to the NIST OSCAL Profile and Catalog schema references for more information:
Only the control implementation information is present within an
OSCAL-based SSP. Each control in the FedRAMP baseline must have a
corresponding implemented-requirement assembly in the
control-implementation assembly.
<!-- metadata --><import-profilehref="https://path/to/xml/FedRAMP_MODERATE-baseline_profile.xml"/><!-- system-characteristics --><!-- system-implementation --><control-implementation><description><p>This field required by OSCAL, but may be left blank.</p><p>FedRAMP requires no specific content here.</p></description><!-- one implemented-requirement assembly for each required control --><implemented-requirementuuid="uuid-value"control-id="ac-1"><!-- Control content cut - See next pages for detail --></implemented-requirement><implemented-requirementuuid="uuid-value"control-id="ac-2"><!-- Control content cut - See next pages for detail --></implemented-requirement><implemented-requirementuuid="uuid-value"control-id="ac-2.1"><!-- Control content cut - See next pages for detail --></implemented-requirement></control-implementation><!-- back-matter -->
Every applicable control must have at least one responsible-role
defined. There must be a separate responsible-role assembly for each
responsible role. OSCAL requires the specified role-id to be valid in
the defined list of roles in the metadata. Controls with a FedRAMP
implementation-status property value of “non-applicable” (see the Implementation Status section)
do not require a responsible-role. FedRAMP further requires that the
specified role-id must also have been referenced in the system-implementationuser assembly. This equates to the FedRAMP requirement of all responsible roles appearing in the Personnel Roles and Privileges table.
With the implemented-requirement assembly, there must be one set-parameter statement for each of the control’s parameters, as specified in the FedRAMP baseline and illustrated in the example representation below. The only exception to this is with nested parameters. Some select parameters contain an assignment parameter within a selection parameter, such as appears in AC-7 (b). In these instances, only the final selected value must be provided. The nested assignment parameter may be ignored.
OSCAL also supports parameter setting at the component level, within a
by-component assembly.
Number of specified Responsible Roles:
count(/*/control-implementation/implemented-requirement[@control-id="ac-2"]/responsible-role)
Responsible Role:
/*/metadata/role[@id=/*/control-implementation/implemented-requirement[@control-id="ac-2"]/responsible-role[1]/@role-id]/title
Check for existence in Personnel Roles and Privileges (Should return a number > 0)
count(/*/system-implementation/user/role-id[string(.)=/*/control-implementation/implemented-requirement[@control-id="ac-2"]/responsible-role/@role-id])
Parameter Value:
/*/control-implementation/implemented-requirement[@control-id="ac-2"]/set-parameter [@param-id="ac-2_prm_1"]/value
FedRAMP only accepts only one of five values for implementation-status:
implemented, partial, planned, alternative, and not-applicable. A
control may be marked “partial” and “planned” (using two separate
implementation-status fields). All other choices are mutually exclusive.
If the implementation-status is partial, the gap must be explained
in the remarks field.
If the implementation-status is planned, a brief description of the
plan to address the gap, including major milestones must be explained in
the remarks field. There must also be a prop
(name="planned-completion-date" ns="https://fedramp.gov/ns/oscal")
field containing the intended completion date. With XML, prop fields
must appear before other sibling fields (such as set-parmeter, responsible-role, etc.), even though that sequence is
counter-intuitive in this situation.
If the implementation-status is alternative, the alternative
implementation must be summarized in the remarks field.
If the implementation-status is not-applicable, the N/A
justification must be provided in the remarks field.
Implementation Status (may return more than 1 result for a given control) :
/*/control-implementation/implemented-requirement[@control-id="ac-1"] /prop[@name="implementation-status"]/@value
Gap Description (If implementation-status="partial"):
/*/control-implementation/implemented-requirement/prop[@name='implementation-status'][@value="partial"][@ns="https://fedramp.gov/ns/oscal"]/remarks/node()
Planned Completion Date (If implementation-status="planned"):
/*/control-implementation/implemented-requirement[@control-id="ac-1"]/prop[@name="planned-completion-date"][@ns="https://fedramp.gov/ns/oscal"]/@value
Plan for Completion (If implementation-status="planned"):
/*/control-implementation/implemented-requirement/prop[@name='implementation-status'][@value="planned"][@ns="https://fedramp.gov/ns/oscal"]/remarks/node()
Not Applicable (N/A) Justification (If implementation-status="na"):
/*/control-implementation/implemented-requirement/prop[@name='implementation-status'][@value="not-applicable"][@ns="https://fedramp.gov/ns/oscal"]/remarks/node()
The FedRAMP implementation-status property at the control’s
implemented-requirement level is a summary of all statement and/or
component level core OSCAL implementation-status designations. It must
be set appropriately based on the least value of child statement
or component level implementation-status designations. When a statement
and/or component level implementation-status designation is not
specified, the FedRAMP implementation-status value is assumed.
Individual statements and/or components may override
implementation-status locally.
FedRAMP accepts only one of five values for control-origination:
sp-corporate, sp-system, customer-configured, customer-provided, and
inherited. Hybrid choices are expressed by identifying more than one
control-origination, each in a separate prop field.
For controls with a control-id ending in "-1", FedRAMP only accepts
sp-corporate and sp-system.
If the control origination is inherited, there must also be a
FedRAMP extension (prop name="leveraged-authorization-uuid"
ns="https://fedramp.gov/ns/oscal") field containing the UUID of the
leveraged authorization as it appears in the
/*/system-implementation/leveraged-authorization assembly.
Number of Control Originations:
count(/*/control-implementation/implemented-requirement[@control-id="ac-2"]/prop[@name="control-origination"][@ns="https://fedramp.gov/ns/oscal"])
Control Origination(could return more than 1 result):
/*/control-implementation/implemented-requirement[@control-id="ac-2"]/prop[@name="control-origination"][@ns="https://fedramp.gov/ns/oscal"][1]/@value
Inherited From: System Name (If control-origination="inherited"):
/*/system-implementation/leveraged-authorization[@uuid=/*/control-implementation/implemented-requirement[@control-id="ac-2"]/prop[@name="leveraged-authorization-uuid"]]/title
Inherited From: Authorization Date (If control-origination="inherited"):
/*/system-implementation/leveraged-authorization[@uuid=/*/control-implementation/implemented-requirement[@control-id="ac-2"]/prop[@name="leveraged-authorization-uuid"]]/date-authorized
Within the OSCAL-based FedRAMP baselines, control statements and control
objectives are tagged with a response-point FedRAMP Extension. Every
control statement designated as a response-point in the baseline must
have a statement with the control’s implemented-requirement assembly.
Please note that control objective response points are used for the SAP and
SAR.
When using a FedRAMP Resolved Profile Catalog, the following query
will identify the response points for a given control.
Within each statement assembly, all responses must be provided within
one or more by-component assemblies. There must always be a component
defined in the system-implementation representing the system as a whole
(“THIS SYSTEM”), even if individual components are defined that
comprise the system. See the Working with Components section for more information.
An OSCAL-based FedRAMP SSP should define individual components of the
system. Components are not just hardware and software. Policies,
processes, FIPS 140 validation information, interconnections, services,
and underlying systems (leveraged authorizations) are all components.
With OSCAL, the content in the cell next to Part a must be broken down
into its individual components and responded to separately.
For Part a
Component - This System
Describes how part a is satisfied holistically, or where the description does not fit with a defined component.
Component - Platform
Describes how part a is satisfied by the platform.
Component - Web-Server
Describes how part a is satisfied by the web server.
Component - Process
Describes how part a is satisfied by an identified process within this organization.
Component - Inherited
Describes what is inherited from the underlying Infrastructure as a Service (IaaS) provider to satisfy part a.
For Part b
Component - This System
Describes how part b is satisfied holistically, or where the description does not fit with a defined component.
Component - Platform
Describes how part b is satisfied by the platform.
Component - Web-Server
Describes how part b is satisfied by the web server.
Component - Process
Describes how part b is satisfied by an identified process within this organization.
Component - Inherited
Describes what is inherited from the underlying Infrastructure as a Service (IaaS) provider to satisfy part b.
Within each of the statement assemblies, all responses appear in one or
more by-component assemblies. Each by-component assembly references a component defined in the system-implementation assembly.
<system-implementation><!-- leveraged-authorization, user --><componentuuid="uuid-value"type="software"><title>Component Title</title><description><p>Description of the component.</p></description><statusstate="operational"/></component><componentuuid="uuid-value"type="process"><title>Process Title</title><description><p>Description of the component.</p></description><statusstate="operational"/><responsible-rolerole-id="admin-unix"><party-uuid>3360e343-9860-4bda-9dfc-ff427c3dfab6</party-uuid></responsible-role></component></system-implementation><control-implementation><!-- cut --><implemented-requirementuuid="uuid-value"control-id="ac-2"><statementuuid="uuid-value"statement-id="ac-2_smt.a"><by-componentuuid="uuid-value"component-uuid="uuid-of-software-component"><description><p>Describe how the software component is satisfying the control.</p></description></by-component><by-componentuuid="uuid-value"component-uuid="uuid-of-process-component"><description><p>Describe how the process satisfies the control.</p></description></by-component><!-- repeat by-component assembly for each component related to part a. --></statement><!-- repeat statement assembly for statement part (b, c, etc.) as needed. --></implemented-requirement></control-implementation><!-- back-matter -->
There must always be a “This System” component in the SSP. This is used in several ways:
Holistic Overview: The SSP author may wish to provide a more
holistic overview of how several components work together, even if
details are provided individually in other by-component assemblies.
Catch-all: Any control response that does not cleanly align with
another system component may be described in the “This System”
component.
Legacy SSP Conversion: When converting a legacy SSP to OSCAL,
the legacy control response statements may initially be associated
with the “This System” component until the SSP author is able
to provide responses for individual components.
<system-implementation><!-- leveraged-authorization, user --><componentuuid="uuid-value"type="this-system"><title>This System</title><description><p>Description of the component.</p></description><statusstate="operational"/></component></system-implementation><control-implementation><!-- cut --><implemented-requirementuuid="uuid-value"control-id="ac-2"><statementuuid="uuid-value"statement-id="ac-2_smt.a"><by-componentuuid="uuid-value"component-uuid="uuid-of-this-system-component"><description><p>Describe how individual components are working together.</p><p>Describe how the system - as a whole - is satisfying this statement.</p><p>This can include policy, procedures, hardware, software, etc.</p></description></by-component></statement><!-- repeat statement assembly for statement part (b, c, etc.) as needed. --></implemented-requirement></control-implementation><!-- back-matter -->
NOTES:
Although the name of the component is “This System”,
non-technical solutions may also be discussed here, such as policies
and procedures.
Any time policies, procedures, plans, and similar documentation are
cited in a control response, they must be linked.
For the legacy approach, when responding within the by-component
assembly for “this system”, the link must be within the same by-component assembly where the artifact is cited.
<control-implementation><implemented-requirementuuid="uuid-value"control-id="ac-1"><statementuuid="uuid-value"statement-id="ac-1_smt.a"><by-componentcomponent-uuid="uuid-of-this-system"uuid="uuid-value"><description><p>Describe how Part a is satisfied within the system.</p></description><linkhref="#uuid-of-policy-resource-in-back-matter"rel="policy"/></by-component></statement></implemented-requirement></control-implementation><!-- back-matter -->
For the component approach, use the component representing the policy.
The link should be in the component, but may be added directly to the
by-component as well.
<system-implementation><!-- leveraged-authorization, user --><componentuuid="uuid-value"type="policy"><title>Access Control and Identity Management Policy</title><description><p>An example component representing a policy.</p></description><linkhref="#uuid-of-policy-resource-in-back-matter"rel="policy"/><statusstate="operational"/></component></system-implementation><control-implementation><implemented-requirementuuid="uuid-value"control-id="ac-1"><statementuuid="uuid-value"statement-id="ac-1_smt.a"><by-componentcomponent-uuid="uuid-of-policy-component"uuid="uuid-value"><description><p>Describe how this policy satisfies Part a.</p></description></by-component></statement></implemented-requirement></control-implementation><!-- back-matter -->
For either example above, the policy must be present as a resource in back-matter.
<back-matter><resourceuuid="uuid-value"><title>Access Control and Identity Management Policy</title><rlinkmedia-type="application/pdf"href="./documents/policies/sample_policy.pdf"/><base64filename="sample_policy.pdf"media-type="application/pdf">00000000</base64></resource></back-matter>
For systems that may be leveraged, OSCAL enables a robust mechanism for
providing both inheritance details as well as customer responsibilities
(referred to as consumer responsibilities by NIST). OSCAL is designed to
enable leveraged and leveraging system SSP details to be linked by tools
for validation.
Within the appropriate by-component assembly, include an export
assembly. Use provided to identify a capability that may be inherited by a leveraging system. Use responsibility to identify a customer responsibility. If a responsibility must be satisfied to achieve inheritance, add the
provided-uuid flag to the responsibility field.
<!-- system-implementation --><control-implementation><!-- cut --><implemented-requirementuuid="uuid-value"control-id="ac-2"><statementuuid="uuid-value"statement-id="ac-2_smt.a"><by-componentuuid="uuid-value"component-uuid="uuid-of-this-system-component"><description><p>Describe how the system - as a whole - is satisfying this statement.</p></description><export><responsibilityuuid="uuid-value"><description><p>Leveraging system's responsibilities in satisfaction of AC-2.</p><p>Not linked to inheritance, so this is always required.</p></description><responsible-rolerole-id="customer"/></responsibility></export></by-component><by-componentuuid="uuid-value"component-uuid="uuid-of-software-component"><description><p>Describe how the software is satisfying this statement.</p></description><export><provideduuid="uuid-value"><description><p>Customer appropriate description of what may be inherited.</p></description><responsible-rolerole-id="poc-for-customers"/></provided><responsibilityuuid="uuid-value"provided-uuid="uuid-of-provided"><description><p>Customer responsibilities if inheriting this capability.</p></description><responsible-rolerole-id="customer"/></responsibility></export></by-component></statement></implemented-requirement></control-implementation>
When the current system is inheriting a control from or meeting customer
responsibilities defined by an underlying authorization, the leveraged
system must first be defined as described in the Response: Identifying Inheritable Controls and Customer Responsibilities section, and documented a component int the leveraging system SSP before it may be referenced in a control response. The by-component assembly references these components.
IMPORTANT: The leveraged system may provide a single component
representing the entire leveraged system
or may provide individual system components as well. In either case, the
inherited-uuid property in the component must have the value flag set to the UUID of the leveraged system or component.
<system-implementation><componentuuid="uuid-value"type="this-system"><!-- cut --></component><componentuuid="uuid-value"type="leveraged-system"><title><b>LEVERAGED SYSTEM as a whole (IaaS)</b></title><propname="leveraged-authorization-uuid"value="uuid-of-LA-in-this-SSP"/><propname="inherited-uuid"value="uuid-of-component-in-leveraged-SSP"/></component><componentuuid="uuid-value"type="service"><title>Service Provided by Leveraged System</title><propname="leveraged-authorization-uuid"value="uuid-of-LA-in-this-SSP"/><propname="inherited-uuid"value="uuid-of-component-in-leveraged-SSP"/></component></system-implementation><control-implementation><implemented-requirementuuid="uuid-value"control-id="ac-2"><statementuuid="uuid-value"statement-id="ac-2_smt.a"><by-componentuuid="uuid-value"component-uuid="uuid-of-this-system-component"><description><p>Describe what is satisfied by this system.</p></description></by-component><by-componentuuid="uuid-value"component-uuid="uuid-leveraged-system-component"><description><p>Describe what is inherited from the leveraged system in satisfaction
of this control statement.</p></description><inheritedprovided-uuid="uuid-of-provided"uuid="uuid-value"><description><p>Optional: Information provided by leveraged system.</p></description></inherited><satisfiedresponsibility-uuid="uuid-of-responsibility"uuid="uuid-value"><description><p>Description of how the responsibility was satisfied.</p></description></satisfied></by-component></statement><!-- repeat statement assembly for statement part (b, c, etc.) as needed. --></implemented-requirement></control-implementation><!-- back-matter -->
Use the following XPath queries to retrieve basic control response
information. For any given control response part, tools should list the
name of each component cited by a by-component assembly, as well as the
description.
Number of cited components for AC-2, part a (Integer):
count(/*/control-implementation/implemented-requirement[@control-id="ac-2"]/statement[@statement-id="ac-2_smt.a"]/by-component)
Name of first component related to AC-2, part a:
/*/system-implementation/component[@uuid=/*/control-implementation/implemented-requirement[@control-id="ac-2"]/statement[@statement-id="ac-2_smt.a"]/by-component[1]/@component-uuid]/title
"What is the solution and how is it implemented?" for AC-2, Part (a), first component:
/*/control-implementation/implemented-requirement[@control-id="ac-2"]/statement[@statement-id="ac-2_smt.a"]/by-component[1]/description/node()
Is there a customer responsibility for the first component in AC-2, part a? (true/false):
boolean(/*/control-implementation/implemented-requirement[@control-id="ac-2"]/statement[@statement-id="ac-2_smt.a"]/by-component[1] /prop[@name='responsibility'][@value='customer'])
Customer responsibility statement for the first component in AC-2, part a:
/*/control-implementation/implemented-requirement[@control-id="ac-2"]/statement[@statement-id="ac-2_smt.a"]/by-component[1]/prop[@name='responsibility'][@value='customer']/remarks/node()
NOTES:
Replace “ac-2” with target control-id.
Replace “ac-2_smt.a” with target control statement-id.
Replace “[1]” with “[2]”, “[3]”, etc. as needed to reference
by-componentstatement.