risk-assessment-methodology
SKILL.md
Risk Assessment Methodology Skill
Purpose
This skill provides quantitative risk assessment methodology aligned with Hack23 AB's enterprise risk management framework. It enables security professionals and business leaders to systematically identify, analyze, evaluate, and treat risks using defensible statistical methods that demonstrate cybersecurity consulting expertise through measurable, data-driven risk quantification.
When to Use This Skill
Apply this skill when:
- ✅ Conducting quarterly risk assessments
- ✅ Evaluating risks for new products or services
- ✅ Calculating Annual Loss Expectancy (ALE) for control investments
- ✅ Prioritizing risk treatment based on quantitative impact
- ✅ Documenting risk acceptance decisions
- ✅ Creating risk registers for compliance frameworks
- ✅ Performing threat modeling with financial impact
- ✅ Supporting business case for security controls
- ✅ Responding to client risk assessment inquiries
Do NOT use for:
- ❌ Real-time incident response (use incident-response skill)
- ❌ Vulnerability scoring (use vulnerability-management skill)
- ❌ Code security reviews (use secure-code-review skill)
Risk Assessment Process Flow
flowchart TD
START[🎯 Risk Assessment<br/>Initiation] --> IDENTIFY[📋 Risk Identification<br/>Assets • Threats • Vulnerabilities]
IDENTIFY --> ANALYZE[🔍 Risk Analysis]
ANALYZE --> LIKELIHOOD[📊 Likelihood Assessment<br/>Historical + Industry + Expert]
ANALYZE --> IMPACT[💰 Impact Assessment<br/>Financial • Operational • Reputational]
LIKELIHOOD --> CALC[🔢 Risk Score Calculation<br/>Probability × Impact × 100]
IMPACT --> CALC
CALC --> CATEGORY{Risk Level?}
CATEGORY -->|400-600| CRITICAL[🔴 Critical Risk<br/>Immediate action required]
CATEGORY -->|200-399| HIGH[🟠 High Risk<br/>Priority mitigation needed]
CATEGORY -->|100-199| MEDIUM[🟡 Medium Risk<br/>Planned controls required]
CATEGORY -->|50-99| LOW[🟢 Low Risk<br/>Monitor and accept]
CATEGORY -->|1-49| MINIMAL[⚪ Minimal Risk<br/>Accept risk]
CRITICAL --> TREAT{Treatment<br/>Decision}
HIGH --> TREAT
MEDIUM --> TREAT
LOW --> ACCEPT[✅ Accept Risk<br/>Document in Risk Register]
MINIMAL --> ACCEPT
TREAT -->|Reduce| MITIGATE[🛡️ Implement Controls<br/>Reduce likelihood or impact]
TREAT -->|Transfer| TRANSFER[🤝 Insurance/Outsource<br/>Share financial burden]
TREAT -->|Avoid| AVOID[🚫 Eliminate Activity<br/>Remove risk source]
TREAT -->|Accept| ACCEPT_HIGH[📋 Document Acceptance<br/>CEO approval required]
MITIGATE --> RESIDUAL[📉 Residual Risk<br/>Reassessment]
TRANSFER --> RESIDUAL
AVOID --> RESIDUAL
ACCEPT_HIGH --> RESIDUAL
ACCEPT --> REGISTER[📊 Risk Register<br/>Tracking & Monitoring]
RESIDUAL --> REGISTER
REGISTER --> REVIEW[🔄 Periodic Review<br/>Quarterly/Annual]
REVIEW --> START
style START fill:#1565C0,stroke:#0D47A1,stroke-width:3px,color:#fff
style CRITICAL fill:#D32F2F,stroke:#B71C1C,stroke-width:3px,color:#fff
style HIGH fill:#FF9800,stroke:#F57C00,stroke-width:2px
style MEDIUM fill:#FFC107,stroke:#FFA000,stroke-width:2px
style LOW fill:#4CAF50,stroke:#2E7D32,stroke-width:2px,color:#fff
style MINIMAL fill:#9E9E9E,stroke:#616161,stroke-width:1px
style REGISTER fill:#9C27B0,stroke:#7B1FA2,stroke-width:2px,color:#fff
Likelihood Assessment Framework
Evaluate probability using descriptive categories with quantitative ranges:
| Likelihood | Badge | Probability | Annual Frequency | ARO | Definition | Examples |
|---|---|---|---|---|---|---|
| Almost Certain | 80-99% | 292-361 events/year | 0.8-0.99 | Expected to occur in most circumstances | Daily operational issues, routine maintenance | |
| Likely | 60-79% | 219-291 events/year | 0.6-0.79 | Will probably occur | Weekly service disruptions, staff availability issues | |
| Possible | 40-59% | 146-218 events/year | 0.4-0.59 | Might occur at some time | Monthly supplier issues, seasonal variations | |
| Unlikely | 20-39% | 73-145 events/year | 0.2-0.39 | Could occur but not expected | Quarterly security incidents, annual contract changes | |
| Rare | 5-19% | 18-72 events/year | 0.05-0.19 | May occur only in exceptional circumstances | Multi-year events, rare external factors | |
| Exceptional | <5% | <18 events/year | <0.05 | Rare, once-in-decade event | Black swan events, extreme scenarios |
Likelihood Assessment Methods
Quantitative Data (Preferred):
# Historical frequency analysis
def calculate_aro(events_last_3_years, trend_factor=1.0):
"""Calculate Annual Rate of Occurrence from historical data"""
base_aro = sum(events_last_3_years) / 3
adjusted_aro = base_aro * trend_factor
return min(adjusted_aro, 0.99) # Cap at 99%
# Example: 8 incidents in 3 years, increasing trend
aro = calculate_aro([2, 3, 3], trend_factor=1.2) # = 0.32 (Unlikely)
Qualitative Assessment (When Data Limited):
- Industry benchmarks (DBIR, ENISA Threat Landscape)
- Expert judgment from security team
- Peer comparison with similar organizations
- Threat intelligence feeds
Impact Assessment Framework
Evaluate business impact across multiple dimensions:
| Impact | Badge | Financial | Operational | Reputational | Regulatory |
|---|---|---|---|---|---|
| Catastrophic | >€50K | Complete shutdown | International media | Criminal charges | |
| Critical | €10K-50K | Major disruption | National media | Significant fines | |
| High | €1K-10K | Significant degradation | Industry attention | Moderate penalties | |
| Moderate | €500-1K | Partial service impact | Regional visibility | Minor warnings | |
| Low | €100-500 | Minor inconvenience | Limited local impact | Verbal guidance | |
| Minimal | <€100 | No significant impact | No external visibility | No implications |
Impact Score Mapping
- Catastrophic = 6
- Critical = 5
- High = 4
- Moderate = 3
- Low = 2
- Minimal = 1
Risk Score Calculation
Formula: Risk Score = Likelihood (midpoint %) × Impact Score (1-6) × 100
Calculation Examples
Example 1: Data Breach Risk
- Likelihood: Unlikely (30% midpoint)
- Impact: Critical (5)
- Risk Score: 0.30 × 5 × 100 = 150 → 🟡 Medium Risk
Example 2: DDoS Attack Risk
- Likelihood: Possible (50% midpoint)
- Impact: High (4)
- Risk Score: 0.50 × 4 × 100 = 200 → 🟠 High Risk
Example 3: Ransomware Risk
- Likelihood: Likely (70% midpoint)
- Impact: Catastrophic (6)
- Risk Score: 0.70 × 6 × 100 = 420 → 🔴 Critical Risk
Risk Level Categories
| Risk Level | Score Range | Badge | Management Response | Review Frequency |
|---|---|---|---|---|
| Critical | 400-600 | CEO immediate action, daily monitoring | Daily | |
| High | 200-399 | Weekly executive review | Weekly | |
| Medium | 100-199 | Monthly assessment | Monthly | |
| Low | 50-99 | Quarterly monitoring | Quarterly | |
| Minimal | 1-49 | Acceptance, periodic review | Annual |
Financial Risk Analysis
Single Loss Expectancy (SLE)
Formula: SLE = Asset Value × Exposure Factor
Asset Value Categories:
| Category | Value Range | Examples |
|---|---|---|
| Mission Critical | €100K-500K | Core infrastructure, customer data |
| High Value | €50K-100K | Business applications, intellectual property |
| Standard | €10K-50K | Supporting systems, processes |
| Low Value | €1K-10K | Documentation, utilities |
Exposure Factor Guidelines:
| Exposure | Factor | Description |
|---|---|---|
| Complete Loss | 0.8-1.0 | Total destruction (ransomware, theft) |
| Major Loss | 0.5-0.8 | Significant damage (data corruption) |
| Moderate Loss | 0.2-0.5 | Partial damage (service disruption) |
| Minor Loss | 0.1-0.2 | Limited impact (performance degradation) |
Annual Loss Expectancy (ALE)
Formula: ALE = SLE × ARO
Example Calculation:
# Ransomware attack on CIA Platform
asset_value = 200000 # €200K (Mission Critical)
exposure_factor = 0.9 # 90% loss (Complete Loss)
aro = 0.7 # 70% (Likely based on industry data)
sle = asset_value * exposure_factor # €180K
ale = sle * aro # €126K annually
Value at Risk (VaR) Framework
Formula: VaR = Impact (€) × Probability × Confidence Factor × Time Horizon
VaR Risk Categories:
| Category | VaR Range (€) | Management Action |
|---|---|---|
| Critical | >€200K | Board escalation, immediate mitigation |
| High | €50K-200K | Executive committee, quarterly review |
| Medium | €10K-50K | Risk committee, semi-annual review |
| Low | €1K-10K | Management monitoring, annual review |
| Minimal | <€1K | Acceptance, periodic review |
Risk Treatment Decision Matrix
graph TB
RISK[📊 Risk Identified<br/>with Score] --> EVAL{Risk Level?}
EVAL -->|Critical/High<br/>400-600, 200-399| HIGH_TREAT[🎯 Treatment Required]
EVAL -->|Medium<br/>100-199| MED_TREAT[⚖️ Treatment Evaluation]
EVAL -->|Low/Minimal<br/>1-99| LOW_TREAT[✅ Consider Acceptance]
HIGH_TREAT --> OPTIONS1[Treatment Options]
MED_TREAT --> OPTIONS2[Treatment Options]
LOW_TREAT --> ACCEPT_DIRECT[Accept Risk<br/>Document in Risk Register]
OPTIONS1 --> MITIGATE1[🛡️ Mitigate<br/>Implement controls]
OPTIONS1 --> TRANSFER1[🤝 Transfer<br/>Insurance/Outsource]
OPTIONS1 --> AVOID1[🚫 Avoid<br/>Eliminate activity]
OPTIONS2 --> MITIGATE2[🛡️ Mitigate<br/>Cost-benefit analysis]
OPTIONS2 --> ACCEPT2[📋 Accept<br/>Document rationale]
MITIGATE1 --> COST_BENEFIT{Control Cost<br/>vs ALE?}
TRANSFER1 --> COST_BENEFIT
MITIGATE2 --> COST_BENEFIT
COST_BENEFIT -->|Control < ALE| IMPLEMENT[✅ Implement Control]
COST_BENEFIT -->|Control > ALE| ACCEPT_COST[📋 Accept Risk<br/>Document decision]
AVOID1 --> BUSINESS{Business<br/>Impact?}
BUSINESS -->|Acceptable| ELIMINATE[🚫 Eliminate Risk]
BUSINESS -->|Unacceptable| FIND_ALT[🔄 Find Alternative]
IMPLEMENT --> RESIDUAL[📉 Residual Risk<br/>Assessment]
ACCEPT2 --> REGISTER[📊 Risk Register]
ACCEPT_COST --> REGISTER
ACCEPT_DIRECT --> REGISTER
ELIMINATE --> REGISTER
RESIDUAL --> REEVAL{Still<br/>High/Critical?}
REEVAL -->|Yes| ADDITIONAL[Additional Controls<br/>Required]
REEVAL -->|No| REGISTER
ADDITIONAL --> COST_BENEFIT
style RISK fill:#1565C0,stroke:#0D47A1,stroke-width:3px,color:#fff
style HIGH_TREAT fill:#D32F2F,stroke:#B71C1C,stroke-width:3px,color:#fff
style MED_TREAT fill:#FF9800,stroke:#F57C00,stroke-width:2px
style IMPLEMENT fill:#4CAF50,stroke:#2E7D32,stroke-width:2px,color:#fff
style REGISTER fill:#9C27B0,stroke:#7B1FA2,stroke-width:2px,color:#fff
Cost-Benefit Analysis Formula
Control Value = ALE (Before) - ALE (After) - Control Cost
def control_roi(ale_before, ale_after, control_cost_annual):
"""Calculate return on investment for security control"""
annual_benefit = ale_before - ale_after
net_benefit = annual_benefit - control_cost_annual
roi_percentage = (net_benefit / control_cost_annual) * 100
return {
'annual_benefit': annual_benefit,
'net_benefit': net_benefit,
'roi_percentage': roi_percentage,
'recommendation': 'Implement' if net_benefit > 0 else 'Reject'
}
# Example: MFA implementation
result = control_roi(
ale_before=126000, # €126K ransomware risk
ale_after=12600, # 90% reduction
control_cost_annual=5000 # €5K/year for MFA
)
# Result: €108.4K net benefit, 2068% ROI → Implement
Risk Assessment Templates
Template 1: Comprehensive Risk Assessment
# Risk Assessment: [Risk Name]
**Risk ID:** RSK-2025-XXX
**Assessment Date:** 2025-01-XX
**Assessor:** [Name/Role]
**Status:** Open/Mitigated/Accepted/Closed
## Risk Description
Brief description of the risk scenario.
## Asset Information
- **Primary Asset:** [Asset name]
- **Asset Value:** €X
- **Classification:** [Confidentiality/Integrity/Availability levels]
## Threat & Vulnerability
- **Threat Actor:** [Who/what causes the risk]
- **Threat Motivation:** [Why would they exploit this]
- **Vulnerability:** [What weakness enables exploitation]
- **Attack Vector:** [How the attack occurs]
## Likelihood Assessment
- **Category:** [Exceptional/Rare/Unlikely/Possible/Likely/Almost Certain]
- **Probability:** X%
- **ARO:** X.XX
- **Evidence:** [Historical data, industry benchmarks, expert judgment]
## Impact Assessment
- **Financial:** €X (Category: [Minimal/Low/Moderate/High/Critical/Catastrophic])
- **Operational:** [Description]
- **Reputational:** [Description]
- **Regulatory:** [Description]
- **Impact Score:** X (1-6)
## Risk Calculation
- **Risk Score:** [Probability × Impact × 100] = XXX
- **Risk Level:** 🔴/🟠/🟡/🟢/⚪ [Critical/High/Medium/Low/Minimal]
## Financial Analysis
- **Asset Value:** €X
- **Exposure Factor:** X.X
- **SLE:** €X
- **ALE:** €X
## Current Controls
- [Existing control 1]
- [Existing control 2]
## Recommended Treatment
- **Strategy:** Mitigate/Transfer/Avoid/Accept
- **Proposed Controls:** [List controls]
- **Control Cost:** €X annually
- **Residual Risk Score:** XXX → [Risk Level]
- **Cost-Benefit:** Net benefit €X, ROI X%
- **Recommendation:** Implement/Reject
## Approval
- **Risk Owner:** [Name/Role]
- **Approval Date:** 2025-XX-XX
- **Review Date:** 2025-XX-XX
Template 2: Quick Risk Matrix
| Risk ID | Description | Likelihood | Impact | Score | Level | Treatment | Owner |
|---|---|---|---|---|---|---|---|
| RSK-001 | Data breach | Unlikely (30%) | Critical (5) | 150 | 🟡 Medium | MFA implementation | CTO |
| RSK-002 | DDoS attack | Possible (50%) | High (4) | 200 | 🟠 High | CDN + WAF | CTO |
| RSK-003 | Ransomware | Likely (70%) | Catastrophic (6) | 420 | 🔴 Critical | Backup + EDR | CEO |
Integration with Classification Framework
Align risk assessments with Classification Framework:
CIA Triad Mapping
Confidentiality Impact:
- Very High (C5) → Catastrophic financial impact
- High (C4) → Critical financial impact
- Moderate (C3) → High financial impact
- Low (C2) → Moderate financial impact
- Minimal (C1) → Low financial impact
Integrity Impact:
- Critical (I5) → Catastrophic operational impact
- High (I4) → Critical operational impact
- Moderate (I3) → High operational impact
- Low (I2) → Moderate operational impact
- Minimal (I1) → Low operational impact
Availability Impact:
- Mission Critical (A5) → Catastrophic business impact
- High (A4) → Critical business impact
- Moderate (A3) → High business impact
- Low (A2) → Moderate business impact
- Minimal (A1) → Low business impact
Practical Examples
Example 1: CIA Platform Ransomware Risk
Risk Assessment:
risk_id: "RSK-2025-001"
risk_name: "Ransomware attack on CIA Platform"
asset: "CIA Platform (Production)"
asset_value: 200000 # €200K
likelihood:
category: "Likely"
probability: 0.70
aro: 0.70
evidence: "Industry data (DBIR 2024), phishing susceptibility"
impact:
financial: 180000 # €180K recovery costs
operational: "72-hour downtime"
reputational: "National media coverage"
regulatory: "GDPR breach notification required"
category: "Catastrophic"
score: 6
risk_score: 420 # 0.70 × 6 × 100
risk_level: "Critical"
financial_analysis:
sle: 180000 # €200K × 0.9
ale: 126000 # €180K × 0.70
current_controls:
- "Firewall"
- "Antivirus"
- "User awareness training"
proposed_treatment:
strategy: "Mitigate"
controls:
- "Multi-factor authentication (MFA)"
- "Endpoint detection and response (EDR)"
- "Immutable backups (3-2-1 rule)"
- "Email security gateway"
control_cost_annual: 15000 # €15K
residual_likelihood: 0.07 # 90% reduction
residual_risk_score: 42 # 0.07 × 6 × 100
residual_risk_level: "Minimal"
cost_benefit:
ale_reduction: 113400 # €126K - €12.6K
net_benefit: 98400 # €113.4K - €15K
roi: 656 # 656% ROI
recommendation: "IMPLEMENT IMMEDIATELY"
approval:
risk_owner: "CEO"
approval_date: "2025-01-25"
next_review: "2025-04-25"
Example 2: Black Trigram No Authentication Risk
Risk Assessment:
risk_id: "RSK-2025-015"
risk_name: "No authentication system risk"
asset: "Black Trigram Gaming Platform"
asset_value: 10000 # €10K
likelihood:
category: "Rare"
probability: 0.12
aro: 0.12
evidence: "No user accounts, public content only"
impact:
financial: 500 # €500 reputation recovery
operational: "Minimal—frontend only"
reputational: "Limited local impact"
regulatory: "None—no personal data"
category: "Low"
score: 2
risk_score: 24 # 0.12 × 2 × 100
risk_level: "Minimal"
financial_analysis:
sle: 5000 # €10K × 0.5 (moderate exposure)
ale: 600 # €5K × 0.12
treatment:
strategy: "Accept"
rationale: "Low confidentiality classification. All content is public educational material. No user-specific operations."
controls_considered:
- "Authentication system: €8K/year"
- "Cost-benefit: Negative ROI (€7.4K loss)"
residual_risk: "Same as inherent risk"
risk_acceptance:
documented_in: "Risk_Register.md"
approved_by: "CEO"
review_frequency: "Annual"
trigger_conditions:
- "Introduction of user accounts"
- "Processing of personal data"
- "User-generated content features"
Compliance Mapping
| Risk Assessment Component | ISO 27005 | NIST RMF | CIS Controls v8 |
|---|---|---|---|
| Risk identification | Clause 8.2 | Categorize | 4.1 Asset Management |
| Likelihood assessment | Annex C | Assess | 4.1 Risk Assessment |
| Impact assessment | Annex C | Assess | 4.2 Risk Analysis |
| Risk calculation | Clause 8.3 | Assess | 4.2 Risk Analysis |
| Risk treatment | Clause 8.4 | Select + Implement | 4.3 Risk Response |
| Risk acceptance | Clause 8.4.4 | Authorize | 4.4 Risk Approval |
| Monitoring & review | Clause 9 | Monitor | 4.5 Risk Monitoring |
Standards & Policy References
Core Hack23 ISMS Policies:
- Risk Assessment Methodology - Quantitative framework
- Risk Register - Live risk tracking
- Classification Framework - Impact assessment
- Asset Register - Asset valuation
- Threat Modeling - Threat identification
All Hack23 ISMS Policies: https://github.com/Hack23/ISMS-PUBLIC
Weekly Installs
4
Repository
hack23/ciaGitHub Stars
212
First Seen
10 days ago
Security Audits
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