Category: HITRUST Assessment Types

Shared Responsibility Matrix

Also known as: SRM, Shared Responsibility Model, Responsibility Matrix

Simply put

A Shared Responsibility Matrix (SRM) is a structured document that spells out who is responsible for which security tasks when an organization relies on an outside service provider, such as a cloud vendor. Rather than assuming one party handles everything, it divides duties so both the customer and the provider know what each must do. This helps prevent gaps where a security responsibility is left unassigned.

Formal definition

A Shared Responsibility Matrix (SRM) is a formal responsibility-assignment document that maps specific security and compliance obligations to the parties involved in a service relationship, typically a customer (or contractor) and an external service provider. It clarifies which controls or assessment objectives are owned by the provider, which are owned by the customer, and which are shared, and is often developed collaboratively between the two parties. In frameworks such as CMMC 2.0, an SRM is used to ensure every assessment objective has an assigned owner. Note that the evidence provided describes SRMs primarily in the context of cloud providers (e.g., AWS) and CMMC/NIST SP 800-171; it does not establish an SRM's role or requirements under HIPAA or the HITRUST CSF specifically. Readers applying an SRM to HIPAA or HITRUST contexts should verify how responsibility allocation interacts with business associate agreements and current framework requirements, as these are outside the scope of the cited evidence.

Why it matters

When an organization moves systems or data to an outside service provider, security responsibilities do not automatically transfer in full to either party. A Shared Responsibility Matrix matters because it prevents the dangerous assumption that "the cloud provider handles security" or, conversely, that the customer alone bears every obligation. As AWS frames its own model, security and compliance are shared between the provider and the customer, and clearly documenting that division can help relieve the customer's operational burden while ensuring nothing critical is left unassigned. Unassigned responsibilities are exactly where security gaps and audit failures tend to appear.

In regulatory and assessment contexts, an SRM has become a practical necessity rather than a nicety. Under CMMC 2.0, an SRM is used to ensure that every assessment objective has an assigned owner, and industry practitioners have described a well-constructed SRM as a leading indicator of an organization's likelihood to pass a CMMC assessment. The underlying principle applies broadly: assessors and auditors want evidence that each required control is owned by someone who can demonstrate it is actually performed.

Readers should note an important scope limitation. The evidence supporting this entry concerns cloud providers (such as AWS) and the CMMC 2.0 / NIST SP 800-171 ecosystem. It does not establish any specific role for an SRM under the HIPAA Rules or the HITRUST CSF. In a HIPAA context, responsibility allocation between a covered entity and a business associate is generally governed through a business associate agreement, and an SRM is not a substitute for one. Organizations applying an SRM to HIPAA or HITRUST work should verify how it interacts with their BAAs and the current requirements of the applicable framework.

Who it's relevant to

Compliance and security officers using cloud or third-party services

Officers responsible for overseeing outsourced or cloud-hosted systems use an SRM to document which safeguards their organization retains and which the provider performs. This helps them avoid the assumption that adopting a compliant provider automatically covers all of their own obligations, and it supports clearer evidence during audits and assessments.

Contractors and organizations pursuing CMMC 2.0

For defense contractors and other organizations subject to CMMC 2.0 and NIST SP 800-171, an SRM is directly relevant because it is used to ensure every assessment objective has an assigned owner. Practitioners have described it as a strong indicator of assessment readiness, making it a core piece of preparation documentation.

External service providers (ESPs) and cloud vendors

Providers such as cloud vendors participate in building the SRM so that their customers understand precisely where the provider's responsibilities end and the customer's begin. Collaborative development helps both sides align on the boundary between the shared environment and the customer-controlled environment.

HIPAA and HITRUST professionals (with caution)

Privacy and security professionals working under HIPAA or the HITRUST CSF may find the SRM concept useful for clarifying responsibilities with vendors, but should treat this cautiously. The cited evidence does not establish SRM requirements for these frameworks, and HIPAA responsibility allocation between covered entities and business associates is generally handled through business associate agreements. Verify how any SRM interacts with your BAAs and current framework requirements.

Inside SRM

Responsibility Assignment

A structured mapping that allocates specific controls or safeguard obligations between parties, typically indicating which party is responsible, accountable, or shares responsibility for a given control. In HIPAA-related arrangements, this often reflects the division of duties between a covered entity and a business associate, or between a customer and a service provider.

Control-Level Granularity

A breakdown of individual controls (for example, mapped to Security Rule administrative, physical, and technical safeguards, or to HITRUST CSF control references) so that responsibility can be assigned at a specific control level rather than only at a broad, general level.

Shared and Delineated Duties

Identification of controls that are the sole responsibility of one party versus those that are shared, clarifying handoffs and dependencies. This helps distinguish, for instance, obligations a cloud or hosting provider manages from those the customer retains.

Relationship Context

Documentation of the underlying relationship the matrix supports, such as a business associate or subcontractor arrangement. Because HIPAA obligations attach through defined relationships (often formalized in a business associate agreement), the matrix generally complements, rather than replaces, the contractual instrument.

Reference Alignment

Cross-references to the applicable framework or regulatory basis (for example, HIPAA Security Rule safeguards or the applicable HITRUST CSF version) so that each assigned responsibility can be traced back to a specific requirement. Readers should confirm mappings against the current regulation or current HITRUST CSF version.

Common questions

Answers to the questions practitioners most commonly ask about SRM.

Is a Shared Responsibility Matrix (SRM) a type of HITRUST assessment?

No. An SRM is a responsibility-assignment tool, not an assessment type. It documents which party (for example, a cloud service provider versus its customer) is responsible for implementing, operating, or sharing responsibility for specific controls. It is used to support compliance and assurance activities, but it does not itself constitute a HITRUST assessment or certification. Readers should not confuse the SRM with the distinct assessment offerings defined in the current HITRUST CSF program.

Does having an SRM in place mean a covered entity or business associate has transferred its HIPAA obligations to its service provider?

Generally, no. An SRM clarifies who performs which control activities, but it does not, by itself, transfer legal accountability. Under HIPAA, obligations attach through defined relationships and, where applicable, through business associate agreements. A covered entity typically remains accountable for its overall compliance posture even when a service provider performs certain controls. The SRM helps document expectations, but legal responsibility is governed by the underlying contracts and the applicable regulatory text, which readers should verify.

How should an SRM handle controls marked as shared between two parties?

For controls identified as shared, the SRM should generally describe the specific portion each party performs rather than simply labeling the control shared. For example, one party may manage the underlying infrastructure while the other configures and monitors application-level settings. Documenting the boundary of each party's responsibility helps avoid gaps where both parties assume the other is responsible. The level of detail needed will typically depend on the control and the service model.

Who should review and approve an SRM, and how often?

An SRM is typically reviewed by both parties to the arrangement, often involving compliance, security, and contracting stakeholders, so that each side confirms the responsibilities assigned to it. Review is generally warranted when the service scope changes, when contracts or business associate agreements are updated, or on a periodic basis aligned with an organization's governance cycle. Specific timing depends on organizational policy and any requirements in the current HITRUST CSF version or applicable agreements.

How does an SRM relate to a business associate agreement (BAA)?

The two are complementary but distinct. A BAA is the contractual instrument that establishes permitted uses and required safeguards between the parties, while an SRM is an operational tool that maps who performs which control activities. An SRM can help operationalize expectations that support the BAA, but it does not replace the BAA and does not by itself create or alter legal obligations. Where the two documents address overlapping topics, organizations should ensure they are consistent.

Can an SRM be used to satisfy HIPAA Security Rule documentation expectations?

An SRM can support documentation of how administrative, physical, and technical safeguards are allocated between parties, which may be useful evidence in demonstrating that responsibilities are defined. However, it is one input rather than a complete solution; it does not substitute for a risk analysis, policies and procedures, or other required documentation. Organizations should confirm what documentation is expected against the current regulatory text and note that state law or the HITECH Act may impose additional requirements.

Common misconceptions

A Shared Responsibility Matrix by itself satisfies HIPAA compliance or transfers legal liability to a vendor.

An SRM is generally a responsibility-assignment and documentation tool, not a compliance determination. Under HIPAA, obligations attach to covered entities and business associates through defined relationships and agreements; documenting who performs a control does not, by itself, establish compliance or fully shift regulatory accountability. Actual liability allocation depends on the governing agreements and applicable law, which readers should verify.

An SRM is a type of HITRUST assessment.

An SRM is a responsibility-allocation tool used to clarify which party handles which controls; it is not itself an assessment type. It may be used alongside an assessment to document shared or inherited controls, but completing an SRM is distinct from undergoing any evaluation or certification.

If a control is assigned to a service provider, the customer has no remaining obligations for it.

Many controls are shared or have customer-side configuration and oversight responsibilities even when a provider manages the underlying infrastructure. A responsibility marked as the provider's may still require the customer to verify, configure, or monitor its portion, and addressable specifications remain obligations that must be addressed rather than ignored.

Best practices

Map responsibilities at the individual control level and align each entry to the applicable framework reference (such as HIPAA Security Rule safeguards or the current HITRUST CSF version), verifying mappings against current guidance.

Ensure the matrix is consistent with, and referenced by, the governing business associate agreement or service contract, since HIPAA obligations attach through those defined relationships rather than through the matrix alone.

Explicitly identify shared controls and document the specific customer-side actions required, so that responsibilities marked to a provider do not leave gaps in configuration, oversight, or monitoring.

Distinguish required and addressable implementation specifications when assigning responsibility, and record how addressable items are being handled rather than treating them as optional.

Review and update the matrix periodically and when relationships, services, or the underlying framework version change, keeping version and date information for auditability.

Confirm the scope and limitations of the matrix in writing, noting that it documents responsibility allocation and does not by itself establish HIPAA compliance or account for additional state law or HITECH obligations.