Security Model Decision Matrix

What Is a Security Model Decision Matrix

A security model decision matrix helps organizations select the appropriate access control and security architecture model based on their specific requirements, regulatory environment, and operational constraints. Security models define the rules governing how subjects (users, processes) interact with objects (files, resources, systems) and form the theoretical foundation for implementing access control in any system.

Choosing the wrong security model leads to either excessive restriction (impeding business operations) or insufficient protection (creating vulnerabilities). This tool guides you through the tradeoffs between models to match your organization's actual needs.

Security Model Overview

Model	Full Name	Core Principle	Best For
DAC	Discretionary Access Control	Resource owners control access	General-purpose systems, file sharing
MAC	Mandatory Access Control	System-enforced labels and clearances	Military, classified data, high-security environments
RBAC	Role-Based Access Control	Access determined by job roles	Enterprise applications, healthcare, finance
ABAC	Attribute-Based Access Control	Access based on attributes and policies	Dynamic environments, cloud, context-aware systems
Bell-LaPadula	—	No read up, no write down	Confidentiality-focused (military/government)
Biba	—	No write up, no read down	Integrity-focused (financial, medical)
Clark-Wilson	—	Well-formed transactions, separation of duties	Commercial transaction integrity
Zero Trust	—	Never trust, always verify	Modern enterprise, cloud-native, remote workforce

Decision Factors

When selecting a security model, evaluate these dimensions:

• Data sensitivity — Classified or regulated data (PHI, PCI, CUI) may require MAC or mandatory integrity models. General business data works well with RBAC.
• Organizational structure — Hierarchical organizations with well-defined roles suit RBAC. Dynamic organizations with cross-functional teams may need ABAC.
• Regulatory requirements — HIPAA favors RBAC with audit trails. Government classified systems require MAC (Bell-LaPadula). Financial systems benefit from Clark-Wilson's separation of duties.
• Scale and complexity — RBAC manages thousands of users efficiently through role assignments. ABAC handles complex, contextual policies but requires more infrastructure.
• Cloud vs on-premises — Cloud-native environments often benefit from ABAC and Zero Trust models. Traditional on-premises systems frequently use RBAC with DAC overlay.

Common Use Cases

• Architecture planning: Select the right access control model when designing a new application or system
• Compliance mapping: Determine which security model satisfies specific regulatory requirements (HIPAA, PCI DSS, CMMC, FedRAMP)
• Security certification study: Understand formal security models for CISSP, CISM, and CompTIA Security+ certification exams
• Migration assessment: Evaluate whether your current security model is adequate when migrating to cloud or adopting Zero Trust
• Vendor evaluation: Assess whether a vendor's access control implementation aligns with your security model requirements

Best Practices

1. Layer models rather than choosing one — Most real-world systems combine models: RBAC for base permissions, ABAC for contextual rules, and Zero Trust principles for continuous verification.
2. Start with RBAC for enterprise applications — RBAC is the most practical starting point for most organizations. It maps naturally to organizational structures and is well-supported by identity providers.
3. Add ABAC for context-sensitive decisions — When you need to consider time of day, device type, location, or risk score in access decisions, layer ABAC policies on top of RBAC roles.
4. Apply least privilege regardless of model — Every model benefits from granting only the minimum access required. Regularly review and remove unnecessary permissions.
5. Adopt Zero Trust principles for modern environments — Regardless of your base model, apply Zero Trust's "verify explicitly, least privilege, assume breach" principles to all access decisions.