STRIDE Security Methodology

Guide for comprehensive security analysis using the STRIDE threat modeling framework, vulnerability assessment, and security architecture evaluation.

When to Use This Skill

Activate when:

•Conducting security threat modeling
•Performing vulnerability assessments
•Evaluating security architecture
•Creating security review documentation
•Generating threat model diagrams
•Assessing security posture of applications

STRIDE Framework

STRIDE categorizes security threats into six categories:

S - Spoofing

Identity theft/impersonation threats

•User authentication bypass
•Session hijacking
•Credential theft
•Certificate spoofing

T - Tampering

Data modification threats

•SQL injection
•Parameter manipulation
•Man-in-the-middle attacks
•Data store manipulation

R - Repudiation

Deniability threats

•Log tampering
•Missing audit trails
•Insufficient logging
•Non-repudiation failures

I - Information Disclosure

Data exposure threats

•Sensitive data leakage
•Error message exposure
•Directory traversal
•Improper access controls

D - Denial of Service

Availability threats

•Resource exhaustion
•Rate limiting bypass
•Memory leaks
•Infinite loops

E - Elevation of Privilege

Authorization bypass threats

•Privilege escalation
•Role bypass
•Insecure direct object reference
•Broken access control

Security Analysis Process

Phase 1: Asset Identification

•Identify critical data assets
•Map data flows and trust boundaries
•Identify entry points and exit points
•Document authentication mechanisms
•List third-party dependencies

Phase 2: Threat Modeling

•Apply STRIDE to each component
•Identify threat scenarios
•Assess likelihood and impact
•Document attack vectors
•Create threat diagrams

Phase 3: Vulnerability Assessment

•Static code analysis
•Dependency vulnerability scanning
•Configuration review
•Authentication/authorization testing
•Input validation analysis

Phase 4: Risk Prioritization

•Calculate risk scores
•Prioritize by business impact
•Identify quick wins
•Create remediation roadmap
•Document mitigations

Threat Model Template

markdown

## Threat: [STRIDE Category] - [Threat Name]

### Description
[Detailed threat description]

### Attack Vector
[How the attack could be executed]

### Affected Components
- [Component 1]
- [Component 2]

### Risk Assessment
- **Likelihood**: High/Medium/Low
- **Impact**: High/Medium/Low
- **Risk Score**: [Likelihood × Impact]

### Mitigation
- [Mitigation step 1]
- [Mitigation step 2]

### Verification
- [How to verify mitigation is effective]

Mermaid Diagram Patterns

Data Flow Diagram

mermaid

graph LR
    A[User] -->|HTTPS| B[Load Balancer]
    B -->|Internal| C[App Server]
    C -->|Query| D[(Database)]
    C -->|API| E[External Service]

    style B fill:#f9f,stroke:#333
    style D fill:#bbf,stroke:#333

Trust Boundary Diagram

mermaid

graph TB
    subgraph "Untrusted Zone"
        A[Internet Users]
    end

    subgraph "DMZ"
        B[Web Server]
    end

    subgraph "Trusted Zone"
        C[App Server]
        D[(Database)]
    end

    A --> B
    B --> C
    C --> D

Security Report Structure

markdown

# Security Assessment Report

## Executive Summary
- **Overall Risk Level**: [Critical/High/Medium/Low]
- **Critical Issues**: [Count]
- **High Issues**: [Count]
- **Recommendations**: [Top 3 actions]

## Threat Model Analysis
### STRIDE Coverage
- Spoofing: [Finding count]
- Tampering: [Finding count]
- Repudiation: [Finding count]
- Information Disclosure: [Finding count]
- Denial of Service: [Finding count]
- Elevation of Privilege: [Finding count]

## Architecture Diagram
[Mermaid diagram with trust boundaries]

## Findings

### Critical
1. [Finding with STRIDE category]

### High Priority
1. [Finding with STRIDE category]

## Remediation Roadmap
### Immediate (0-7 days)
- [Action items]

### Short-term (1-4 weeks)
- [Action items]

### Long-term (1-3 months)
- [Action items]

Key Principles

•Defense in Depth: Multiple security layers
•Least Privilege: Minimal access rights
•Secure by Default: Safe default configurations
•Fail Securely: Handle errors safely
•Zero Trust: Verify everything, trust nothing
•Data Classification: Protect based on sensitivity