RS — Respond NIST CSF 2.0

NIST CSF 2.0 Respond Function:
Incident Response Planning & Execution

The Respond function covers everything that happens after an incident is declared — from containment and forensic analysis to regulatory notification and stakeholder communication.

A breach without a response plan is expensive. A breach with a response plan is contained. The difference — in regulatory fines, customer trust, and remediation cost — is measurable and significant. NIST CSF Respond provides the structure for building that plan before you need it.

In NIST CSF 2.0, Respond has four categories that mirror the lifecycle of an incident: management (declaring and managing the incident), analysis (understanding what happened), communication (telling the right people at the right time), and mitigation (containing and eradicating the threat). Most SMB incident response failures trace back to RS.MA — either the plan doesn’t exist, or nobody knows where it is when an incident occurs.

Regulatory timelines are unforgiving. HIPAA’s 60-day breach notification window, state laws with 30-day requirements, and the SEC’s 4-business-day material incident disclosure rule all require pre-existing process — you cannot build notification capability during an active breach. RS.CO is the control that maps to these obligations.

The 4 Respond Categories

RS.MA
Incident Management
Documented incident response plan, defined roles and escalation paths, criteria for declaring an incident, and integration with business continuity.
RS.AN
Incident Analysis
Forensic investigation, root cause determination, scope assessment, and impact estimation to inform response decisions and regulatory disclosures.
RS.CO
Incident Response Reporting & Communication
Internal escalation protocols, external notification to regulators and affected parties, legal counsel engagement, and public communications strategy.
RS.MI
Incident Mitigation
Containment actions, system isolation, eradication of the threat, and validation that affected systems are clean before restoration.

Common SMB Gaps in the Respond Function

Regulatory Notification Requirements

NIST CSF does not set notification timelines, but RS.CO maps directly to obligations that do. HIPAA requires covered entities to notify affected individuals within 60 days of breach discovery, HHS within 60 days, and media in breaches affecting 500+ individuals in a state. Most state breach notification laws require 30-day or 72-hour notice. If your organization accepts payment cards, PCI-DSS requires notification to your acquiring bank within 24 hours of suspected compromise.

The common thread: all of these timelines are measured from discovery, not from breach. An organization with a mature Detect function discovers breaches early, which compresses how much of the notification window is already consumed before you even start your RS.CO process. Detect and Respond are architecturally linked.

Frequently Asked Questions: NIST CSF Respond

What is the NIST CSF Respond function?
Respond covers what your organization does when a security event occurs: incident containment (RS.MI), forensic analysis (RS.AN), stakeholder and regulatory communication (RS.CO), and incident management and planning (RS.MA). It is the function that determines whether a breach becomes a controlled event or a crisis.
Does NIST CSF require an incident response plan?
RS.MA explicitly requires a documented incident response plan with defined roles, escalation paths, and decision-making authority. It is one of the most auditor-focused controls and among the first things a cyber insurer or regulator will ask for after a breach.
What are the notification requirements under NIST CSF Respond?
NIST CSF does not mandate specific notification timelines, but RS.CO maps to regulatory requirements: HIPAA requires breach notification within 60 days, many state laws require 30 days, and the SEC cybersecurity rules require public company disclosure within 4 business days of a material incident. The IR plan must account for all applicable timelines in advance.
How often should we test our incident response plan?
Tabletop exercises annually at minimum; functional drills every one to two years. Most SMBs skip testing entirely — the gap is discovered during real incidents, when the cost of that gap is highest. Cyber insurance policies increasingly require demonstrated IR capability as a condition of coverage.

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