Comprehending Threat Modeling

Threat modeling is an essential practice for the AZ-400 exam and for securing real‐world systems. By identifying vulnerabilities early in the development lifecycle, you reduce risk, improve resilience, and deliver more trustworthy applications.

In this guide, we’ll break down threat modeling into four core phases:

Define Security Goals
Create an Architectural Diagram
Identify Potential Threats
Design and Implement Countermeasures

1. Define Security Goals

Before you begin, clarify what you’re protecting and why. Strong objectives ensure your team focuses on the assets and risks that matter most.

Common security goals:

Confidentiality: Protect user data from unauthorized disclosure
Integrity: Ensure transactions and records remain unaltered
Availability: Keep services operational under heavy load
Compliance: Meet regulatory requirements such as GDPR or HIPAA

Note

Document your security goals clearly and align them with business requirements. This will guide every subsequent decision.

2. Create an Architectural Diagram

A visual representation of your system highlights data flows, trust boundaries, and critical interfaces. Include:

Front-end clients (web, mobile)
Back-end services and APIs
Databases or storage systems
External dependencies (third-party services, cloud resources)
Network boundaries, firewalls, and trust zones

flowchart LR
  A[User Browser] --> B[Web Server]
  B --> C[Application Server]
  C --> D[(Database)]
  C --> E[External API]

This diagram makes it easier to spot exposed components and entry points for attackers.

3. Identify Potential Threats

With your architecture in hand, enumerate every possible risk. A structured approach—such as STRIDE—helps cover all categories:

STRIDE Category	Threat Description
Spoofing	Pretending to be another user or system component
Tampering	Unauthorized modification of data or code
Repudiation	Denial of performed actions
Information Disclosure	Exposure of sensitive data
Denial of Service	Resource exhaustion or service interruptions
Elevation of Privilege	Gaining higher access than intended

Note

Use a spreadsheet or a threat-modeling tool to track each threat, its likelihood, and impact.

4. Design and Implement Countermeasures

For every identified threat, define controls to prevent, detect, or mitigate its impact. Below is an example mapping:

Countermeasure Type	Examples
Encryption	TLS for in-transit, AES-256 at rest
Access Control	RBAC, MFA, OAuth 2.0
Input Validation	Whitelist validation, parameterized queries
Network Protection	Firewalls, API gateways, WAFs
Rate Limiting & Throttling	API throttling, circuit breakers
Monitoring & Logging	SIEM integration, anomaly detection

Implementation Tips:

Integrate controls early in CI/CD pipelines
Automate security testing (SAST, DAST)
Conduct regular red team exercises and audits

Warning

Security is not a one-off task. Continuously revisit your threat model as your architecture evolves.

Links and References

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