Contain Incidents (RS.MI-01) — NIST CSF 2.0 Subcategory

SubcategoryRS.MI-01 — Contain Incidents

FunctionRS — Respond CategoryRS.MI — Incident Mitigation

Official CSF Core outcome
Incidents are contained

Official CSF 2.0 outcome

RS.MI-01: Incidents are contained.

NIST places this Subcategory within RS.MI — Incident Mitigation and the RS — Respond Function. The statement defines an outcome; it does not prescribe one technology, control set, or maturity level.

What this outcome asks the organization to achieve

Contain Incidents should be understood as an observable organizational condition, not merely an activity. The organization should be able to explain the scope, owner, decision criteria, operating process, and evidence that demonstrate the outcome.

Within Incident Mitigation, the outcome contributes to containment, eradication, risk tradeoffs, and preventing recurrence or spread. Achievement may require policy, process, people, technology, supplier coordination, and assurance working together.

The appropriate implementation depends on mission, business impact, threat exposure, legal and contractual duties, architecture, and risk appetite. A small organization and a large enterprise can pursue the same outcome through different means.

Implementation considerations

Use the following questions and priorities to turn the outcome into a controlled, measurable capability. They are original Bare Metal Cyber guidance and should be tailored to the environment.

Define the exact organizational scope in which “Contain Incidents” must be achieved.
Assign an accountable outcome owner and identify the teams that operate, support, or independently assess the capability.
Translate the outcome into measurable requirements using the organization’s risk strategy, architecture, obligations, and operating context.
Select containment actions based on incident scope, business impact, evidence needs, and safety.
Remove malicious access, artifacts, persistence, and exploited conditions.
Document exceptions, compensating measures, expiration dates, and reassessment triggers.
Test the outcome using normal operations, a negative or failure condition, and a material change scenario.

Evidence to retain

Evidence should be strong enough for an operator to troubleshoot the capability, a risk owner to make a decision, and an independent reviewer to verify the assessment. Prefer current operational evidence over policy statements alone.

Containment and eradication action records
Change approvals and emergency action authority
Validation scans, telemetry, and recurrence monitoring
Evidence of ownership, approval, exceptions, and corrective actions
A current measurement or test showing whether the outcome is achieved in scope

Using this outcome in an Organizational Profile

In a Current Profile, record whether RS.MI-01 is achieved for the selected scope, the evidence used, important limitations, and any accepted residual risk. Avoid a simple yes-or-no answer when coverage or effectiveness varies across assets, suppliers, locations, or business services.

In a Target Profile, describe the target condition, priority, accountable owner, dependencies, resources, and the evidence that will demonstrate achievement. The gap between Current and Target becomes a managed improvement action rather than a vague aspiration.

Scope and business or mission context
Current achievement statement and supporting evidence
Target achievement statement and success criteria
Gap, priority, owner, dependencies, and target date
Exceptions, residual risk, and reassessment triggers

Common failure modes

The following failure patterns are especially relevant to this Category. They should be tested rather than assumed absent.

Containment is delayed while teams seek perfect certainty.
Eradication removes visible artifacts but not access paths or root causes.
Actions are taken without preserving evidence or understanding dependencies.
The organization declares success without sustained monitoring for recurrence.
The organization marks the outcome complete without defining the assessed scope.
Evidence demonstrates that an activity occurred but not that the intended outcome is sustained.

Relationship to the wider CSF

RS.MI-01 depends on and supports outcomes across the other CSF Functions. Governance establishes direction and accountability; Identify clarifies context and risk; Protect applies safeguards; Detect provides visibility; Respond manages incidents; and Recover restores operations.

Use the parent Category and Function profiles to understand the broader objective, then examine adjacent Subcategories for dependencies and sequencing. The CSF does not require the published order to be the implementation order.

Source, scope, and attribution

The Subcategory identifier and official outcome are reproduced from Appendix A of NIST CSWP 29, The NIST Cybersecurity Framework (CSF) 2.0. The page title after the identifier, explanatory guidance, implementation considerations, evidence suggestions, and failure modes are original Bare Metal Cyber educational material.

NIST’s online Reference Tool is the appropriate place to obtain current Implementation Examples and Informative References, which may change more frequently than the Core taxonomy.

Certification relevance

This subject appears in or supports the following certification bodies of knowledge:

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