Threat Model Score Calculator

About the Threat Model Score Calculator

STRIDE is Microsoft's threat modeling methodology that categorizes threats into six types: Spoofing, Tampering, Repudiation, Information Disclosure, Denial of Service, and Elevation of Privilege. Each category maps to a specific security property violation and helps teams systematically identify threats in system designs.

This calculator lets you score each STRIDE category on a 1–5 scale based on your assessment of the threat level for a specific system or component. It produces per-category scores, an aggregate risk score, and an overall threat level. Use it during design reviews, security architecture assessments, and threat modeling workshops to quantify and prioritize identified threats.

When This Page Helps

STRIDE provides comprehensive coverage of threat types, but without scoring, all identified threats appear equal. This calculator adds quantitative scoring to STRIDE analysis, enabling teams to prioritize which threats to address first based on severity rather than treating all threats equally.

How to Use the Inputs

1. Rate each STRIDE category from 1 (Low) to 5 (Critical) for your system.
2. Spoofing: Can an attacker impersonate a legitimate user or service?
3. Tampering: Can data be modified in transit or at rest?
4. Repudiation: Can actions be denied without accountability?
5. Information Disclosure: Can sensitive data be exposed?
6. Denial of Service: Can the service be disrupted?
7. Elevation of Privilege: Can an attacker gain unauthorized access levels?
8. Review the aggregate score and per-category breakdown.

Example Calculation

Tips & Best Practices

• Rate each category independently based on your specific system architecture.
• Use STRIDE-per-element by applying the model to each component in your data flow diagram.
• Map mitigations to specific STRIDE categories to ensure comprehensive coverage.
• Re-score after implementing mitigations to measure security improvement.
• Involve developers, architects, and security engineers for balanced scoring.
• Focus remediation effort on the highest-scoring categories first.

The STRIDE Framework

Developed by Microsoft, STRIDE provides a systematic way to think about threats by categorizing them into six types. Each category corresponds to a violated security property: Authentication, Integrity, Non-repudiation, Confidentiality, Availability, and Authorization.

Scoring Methodology

Rate each category based on: exploitability (how easy is it), impact (how bad if exploited), existing controls (what mitigations are in place), and likelihood (how probable given your threat landscape). A score of 5 means critical risk with inadequate controls.

Integration with Development

Threat modeling is most valuable when integrated into the development lifecycle. Include it in design reviews, update scores after each sprint, and track aggregate scores as a security KPI. Automated tools can help maintain threat models as systems evolve.

Common STRIDE Patterns

Web applications typically have highest risk in Spoofing and Information Disclosure. APIs face Tampering and Elevation risks. Microservices architectures face amplified DoS risks across service dependencies. Understanding these patterns helps focus the assessment.

Frequently Asked Questions

• What does each STRIDE category mean?

  Spoofing: identity falsification. Tampering: data modification. Repudiation: denying actions. Information Disclosure: data exposure. Denial of Service: availability disruption. Elevation of Privilege: unauthorized access escalation. Each maps to a core security property.

• When should I perform threat modeling?

  Ideally during the design phase before implementation. Also perform it when major architectural changes occur, when new data flows are added, during security reviews, and when integrating with external systems. Earlier modeling costs less to act on.

• How does STRIDE compare to other threat modeling methods?

  STRIDE is threat-centric (focused on attacker actions). PASTA is risk-centric (focused on business impact). VAST is process-centric (integrated into DevOps). Attack trees are detailed technical maps. STRIDE is the most widely adopted due to its simplicity and completeness.

• What security controls map to each STRIDE category?

  Spoofing → Authentication. Tampering → Integrity controls (hashing, signing). Repudiation → Logging and auditing. Information Disclosure → Encryption and access control. DoS → Rate limiting and redundancy. Elevation → Authorization and least privilege.

• Should every system component be STRIDE-analyzed?

  Prioritize components that handle sensitive data, authentication, or external input. Trust boundaries (where data crosses privilege levels) are the most critical points. For large systems, focus on the top-risk data flows rather than exhaustively analyzing every component.

• How do I present threat model results to management?

  Focus on aggregate scores, highest-risk categories, concrete business impact, and recommended mitigations with cost estimates. The visual score breakdown from this calculator helps non-technical stakeholders understand the threat landscape quickly.