- 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
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
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 |
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 |
- Integrate controls early in CI/CD pipelines
- Automate security testing (SAST, DAST)
- Conduct regular red team exercises and audits
Security is not a one-off task. Continuously revisit your threat model as your architecture evolves.