What it does. Conduct a defensible cybersecurity risk assessment using the NIST SP 800-30 Rev 1 methodology: prepare scope and a risk model, identify threat sources and threat events, identify vulnerabilities and predisposing conditions, determine likelihood and impact, compute risk, and communicate results as a prioritized risk register. Use when an organization needs an actual risk assessment (not a maturity score), when a control framework (CSF, ISO 27001, RMF, SOC 2, PCI) requires a documented risk analysis as input, when leadership asks "what are our top risks and how bad are they", when assessing risk for a new system or major change, or when building a risk register from scratch. This is the methodology that feeds framework selection, ATO packages, and treatment decisions. Keywords: risk assessment, NIST 800-30, threat modeling, likelihood and impact, risk register, risk analysis, threat sources, vulnerabilities, risk determination, qualitative risk, risk matrix, residual risk, risk treatment. Part of mukul975/Anthropic-Cybersecurity-Skills (817 security skills) (mukul975/Anthropic-Cybersecurity-Skills).

Install

• npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill conducting-cyber-risk-assessment-with-nist-800-30, or copy the skill folder into ~/.claude/skills/conducting-cyber-risk-assessment-with-nist-800-30/.
• Raw file: curl -sL https://raw.githubusercontent.com/mukul975/Anthropic-Cybersecurity-Skills/HEAD/skills/conducting-cyber-risk-assessment-with-nist-800-30/SKILL.md

SKILL.md (verbatim)

name: conducting-cyber-risk-assessment-with-nist-800-30
description: >-
  Conduct a defensible cybersecurity risk assessment using the NIST SP 800-30 Rev 1
  methodology: prepare scope and a risk model, identify threat sources and threat events,
  identify vulnerabilities and predisposing conditions, determine likelihood and impact,
  compute risk, and communicate results as a prioritized risk register. Use when an
  organization needs an actual risk *assessment* (not a maturity score), when a control
  framework (CSF, ISO 27001, RMF, SOC 2, PCI) requires a documented risk analysis as input,
  when leadership asks "what are our top risks and how bad are they", when assessing risk
  for a new system or major change, or when building a risk register from scratch. This is
  the methodology that feeds framework selection, ATO packages, and treatment decisions.
  Keywords: risk assessment, NIST 800-30, threat modeling, likelihood and impact, risk
  register, risk analysis, threat sources, vulnerabilities, risk determination, qualitative
  risk, risk matrix, residual risk, risk treatment.
domain: cybersecurity
subdomain: compliance-governance
tags:
- risk-assessment
- nist-800-30
- risk-management
- threat-modeling
- risk-register
- governance
- nist-800-39
- compliance
version: "1.0"
author: andrewibrah
license: Apache-2.0
nist_csf:
- GV.RM-01
- ID.RA-01
- ID.RA-03
- ID.RA-04
- ID.RA-05
mitre_attack:
- T1566
- T1078
- T1190
- T1486
- T1021

Conducting a Cyber Risk Assessment with NIST SP 800-30

When to Use

• When the organization needs a real risk assessment — an analysis of specific threats, likelihoods, and impacts — rather than a maturity score against a framework. (Maturity tells you how mature your practices are; a risk assessment tells you what could hurt you and how badly.)
• When another framework requires a documented risk analysis as a mandatory input: NIST CSF (ID.RA), ISO 27001 (Clause 6.1.2), NIST RMF / 800-37 (the Prepare and Select steps), SOC 2 (CC3), PCI DSS, or HIPAA (§164.308(a)(1)(ii)(A)).
• When standing up or significantly changing a system and you must understand its risk before authorization or go-live.
• When leadership asks for the organization's top risks, ranked, with a rationale they can defend to a board or regulator.
• When building or refreshing an enterprise risk register.

Prerequisites

• An inventory of in-scope assets, systems, and the information types they handle (system boundary defined).
• Access to threat intelligence (internal incident history, sector ISAC feeds, MITRE ATT&CK) to ground threat-event likelihood in observed behavior.
• Vulnerability data (scan results, pen-test findings, configuration/architecture review) for the in-scope systems.
• Business context: which missions/processes the systems support, and what impact to confidentiality, integrity, or availability would mean in business terms.
• Agreement on the risk model and scales before scoring, so results are comparable and repeatable (see references/standards.md).
• Familiarity with the three-tier risk-management context from NIST SP 800-39 (organization, mission/business process, information system).

Workflow

NIST SP 800-30 Rev 1 defines four steps. Steps 1 and 4 bookend the assessment; Step 2 is the analytic core.

1. Prepare for the assessment

Define and document:

• Purpose (e.g., support an authorization decision, inform control selection, satisfy ISO 6.1.2).
• Scope — organizational tier (Tier 1/2/3), systems, and time horizon.
• Assumptions and constraints (e.g., assume an external adversarial threat with moderate capability).
• Information sources — threat, vulnerability, and impact inputs.
• Risk model and analytic approach — the factors (threat source, threat event, vulnerability, likelihood, impact) and the scales (qualitative Very Low–Very High, or semi-quantitative 0–10). Lock these now.

2. Conduct the assessment

Work through the analytic tasks in order. The 800-30 appendices provide the reference taxonomies (D–I).

2a. Identify threat sources (Appendix D). Classify by type: Adversarial (individuals, groups, nation-states — characterize capability, intent, targeting), Accidental (user error), Structural (equipment/software failure), Environmental (natural disasters, infrastructure outages).

2b. Identify threat events (Appendix E). The specific actions a source could take (e.g., "adversary exfiltrates credentials via phishing then moves laterally"). Map adversarial events to MITRE ATT&CK techniques for traceability.

2c. Identify vulnerabilities and predisposing conditions (Appendix F). Weaknesses (missing MFA, unpatched service) and conditions that make exploitation more or less likely (internet exposure, flat network, lack of segmentation).

2d. Determine likelihood (Appendix G). Assess the likelihood that a threat event is initiated (adversarial) or occurs (non-adversarial), and the likelihood it results in adverse impact given the vulnerabilities. Combine into an overall likelihood on the agreed scale.

2e. Determine impact (Appendix H). Magnitude of harm if the event succeeds — to operations, assets, individuals, other organizations, or the nation. Express against the agreed scale and in business terms.

2f. Determine risk (Appendix I). Risk is a function of likelihood and impact. Plot each threat event on the risk matrix (e.g., likelihood × impact → Very Low … Very High). Record the risk level, the contributing factors, and uncertainty/assumptions.

3. Communicate and share results

Produce the risk register and an executive briefing. For each risk: the threat event, affected assets, likelihood, impact, risk level, key contributing vulnerabilities, and a recommended treatment. Rank by risk level so decision-makers see the top risks first.

4. Maintain the assessment

Risk is not static. Define a refresh cadence and the triggers that force re-assessment (new system, major architecture change, significant incident, new threat intel). Track risk-acceptance decisions and treatment progress over time.

5. Drive treatment decisions

Hand the ranked register to risk owners. For each risk choose a treatment — mitigate (add/strengthen controls), transfer (insurance, contractual), avoid (stop the activity), or accept (document residual risk with an authorizing signature). Re-score residual risk after planned controls to show the post-treatment position.

Key Concepts

Tools & Systems

• NIST SP 800-30 Rev 1 — the methodology and Appendices D–I taxonomies (threat sources, events, vulnerabilities, likelihood, impact, risk).
• NIST SP 800-39 — enterprise risk-management context (three tiers).
• MITRE ATT&CK — to enumerate and ground adversarial threat events in observed TTPs.
• Vulnerability scanners / pen-test reports — empirical vulnerability input.
• Threat intel sources — sector ISACs, vendor feeds, internal incident history for likelihood grounding.
• GRC / risk-register tooling — spreadsheet, or platforms such as ServiceNow GRC, Archer, OneTrust, to store and track the register.
• FAIR (optional) — a quantitative model if leadership wants risk expressed in dollar ranges rather than qualitative bands.

Common Scenarios

• CSF/ISO/SOC 2 needs a risk analysis. Run 800-30 to produce the documented assessment those frameworks require as input, then map results to their control sets.
• New system before go-live. Assess threat events against the system's architecture and feed the result into the authorization (RMF Select/Authorize) decision.
• Board wants the top risks. Deliver a ranked register with impacts in business terms and clear treatment recommendations.
• Post-incident. Re-assess the affected systems; the incident updates likelihood evidence and may surface new threat events.
• Annual refresh. Re-score against current threat intel and control changes; show movement in residual risk year over year.

Output Format

Produce a Risk Assessment Report using assets/template.md, containing:

1. Purpose, scope, and tier — what was assessed and why.
2. Assumptions, constraints, and risk model — the factors and scales used (so results are reproducible).
3. Threat sources — by type, with adversarial characterization.
4. Threat events — each with affected assets and ATT&CK mapping where adversarial.
5. Vulnerabilities and predisposing conditions — tied to threat events.
6. Risk register — table: ID, threat event, asset, likelihood, impact, risk level, contributing vulnerabilities, recommended treatment, owner, residual risk.
7. Top risks summary — ranked, in business terms, for leadership.
8. Maintenance plan — refresh cadence and re-assessment triggers.

Use scripts/process.py to score the register from a risk-input JSON (likelihood × impact → risk level on a configurable matrix), rank risks, and emit the register table.

Other files in this skill

• LICENSE
• assets/template.md
• references/standards.md
• scripts/process.py

assets/template.md (verbatim)

Risk Assessment Report (NIST SP 800-30 Rev 1) — Worked Example

Filled example for a mid-size SaaS company assessing its internet-facing application tier. Replace bracketed content for your own assessment.

1. Purpose, Scope, and Tier

• Purpose: Inform control-investment decisions for FY26 and satisfy the documented risk-analysis input required by the company's SOC 2 (CC3) program and ISO 27001 Clause 6.1.2.
• Scope: Internet-facing application tier — customer web portal, its identity provider (IdP), the API gateway, and the data lake behind them.
• Risk-management tier (SP 800-39): Tier 3 (information system), rolling up to Tier 2 (the "Customer Platform" mission).
• Assessment window: FY26 Q2; valid 12 months or until a triggering change.

2. Assumptions, Constraints, and Risk Model

• Assumptions: A financially motivated external adversary of moderate-to-high capability is actively targeting the sector; internal users are trusted but fallible.
• Constraints: Assessment is architecture- and scan-driven; no red-team engagement was run this cycle.
• Risk model: Factors = threat source, threat event, vulnerability/predisposing condition, likelihood, impact. Adversarial threat events are mapped to MITRE ATT&CK.
• Scales: Five-level qualitative (Very Low → Very High). Risk computed via the 800-30 Rev 1 reference 5×5 matrix (see references/standards.md). This matrix was agreed during Prepare and is locked for the cycle.

3. Threat Sources (Appendix D)

4. Threat Events (Appendix E)

5. Vulnerabilities and Predisposing Conditions (Appendix F)

6. Risk Register

(generated by scripts/process.py; likelihood × impact → risk on the 800-30 5×5 matrix, ranked highest-first)

7. Top Risks Summary (for leadership)

1. R-01 — Very High. A successful phish into our identity provider is the single most damaging plausible event: it grants broad access and, on a flat network, fast lateral movement. Recommendation: deploy phishing-resistant MFA (FIDO2) and segment the IdP — this is the highest-leverage control this fiscal year.
2. R-02 — High. Edge-VPN ransomware is a sector-common entry path. Recommendation: emergency-patch the appliance, restrict the management plane, and validate offline backups.
3. R-04 — Moderate. Cloud misconfiguration is likely but bounded; a preventive SCP guardrail collapses the likelihood cheaply.

8. Maintenance Plan

• Cadence: Full re-assessment annually; register reviewed quarterly.
• Re-assessment triggers: new internet-facing system, major architecture change, any incident affecting in-scope assets, or significant new threat intel (e.g., active exploitation of a component we run).
• Tracking: Treatment progress and risk-acceptance signatures recorded in the GRC tool; residual risk re-scored after each control lands to show year-over-year movement.

references/standards.md (verbatim)

NIST SP 800-30 — Standards & Reference

Primary standard

NIST SP 800-30 Revision 1 — Guide for Conducting Risk Assessments

• Publisher: NIST
• Published: September 2012
• Scope: The risk-assessment component of the broader risk-management process.
• URL: https://csrc.nist.gov/pubs/sp/800/30/r1/final

Companion standards

The four-step process (800-30 Rev 1)

1. Prepare — purpose, scope, assumptions/constraints, sources, risk model and scales.
2. Conduct — tasks 2a–2f below.
3. Communicate — risk register + briefing.
4. Maintain — monitoring and refresh.

Conduct tasks and their reference appendices

Threat source types (Appendix D)

• Adversarial — individuals, groups, organizations, nation-states. Characterize by capability, intent, and targeting.
• Accidental — erroneous actions by authorized users.
• Structural — failures of equipment, software, or environmental controls.
• Environmental — natural or man-made disasters, infrastructure outages.

Assessment scales (qualitative / semi-quantitative)

800-30 uses five-level scales. A common qualitative mapping:

Reference 5×5 risk matrix (likelihood × impact → risk)

Document whichever matrix the organization adopts during Prepare; the engine in scripts/process.py defaults to the table above and is configurable.

NIST CSF 2.0 alignment

Risk treatment options

• Mitigate — implement/strengthen controls (re-score residual risk).
• Transfer — insurance or contractual shift.
• Avoid — discontinue the risk-generating activity.
• Accept — document residual risk with an authorizing signature within risk tolerance.

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