Security Model

Security Controls Mapping

Control Domain	Control	Implementation	Status
Identity	Centralized identity provider	Microsoft Entra ID	Enforced
	Managed identity for services	System-assigned on OpenAI, AKS	Enforced
	No shared keys	local_auth_enabled = false on OpenAI, AI Search	Enforced
	RBAC authorization	Key Vault RBAC mode	Default
	Entra ID database auth	PostgreSQL Entra auth	Default (password auth disabled)
Network	Private connectivity	Private endpoints for OpenAI, Key Vault, AI Search, Cosmos DB	Enforced
	No public ingress	public_network_access_enabled = false	Default
	Network segmentation	VNet with dedicated subnets (PE, compute, management, data)	Enforced
	NSG enforcement	NSGs attached to all subnets	Enforced
	DNS internalization	Private DNS zones for all Private Link services	Enforced
	Key Vault network ACLs	Default action: Deny, bypass: None	Default (configurable)
Encryption	Encryption at rest	Azure-managed keys (default)	Enforced
	Customer-managed keys	Optional CMK via Key Vault	Configurable
	Encryption in transit	TLS enforced on all services	Enforced
Data Protection	Key Vault soft delete	90-day retention	Default
	Key Vault purge protection	Enabled	Default
	Cosmos DB backup	Configurable periodic/continuous backup	Default (periodic)
	PostgreSQL backup	Configurable retention (default: 14 days)	Default
Governance	Location restriction	Azure Policy: allowed locations	Default
	Private endpoint audit	Azure Policy: require private endpoints	Default
	Public PaaS denial	Azure Policy: deny public network access	Default
Observability	Centralized logging	Diagnostic settings to Log Analytics	Enforced
	Configurable retention	Log Analytics retention period	Configurable
	Audit trail	All service operations logged	Enforced
Model Governance	Parameterized deployments	Model name, version, capacity as variables	Enforced
	No anonymous model access	Local auth disabled on OpenAI	Enforced
	Configurable quotas	Capacity units per deployment	Configurable

Identity

• Microsoft Entra ID is the control-plane identity authority
• System-assigned managed identities are enabled for OpenAI and AKS
• Key Vault uses RBAC authorization mode by default
• PostgreSQL supports Entra ID authentication (password auth disabled by default)
• No shared keys in the application layer
• No secret-based application access

Network Security

• Public network access disabled on services where supported
• Private endpoint connectivity for OpenAI, Key Vault, AI Search, and Cosmos DB
• PostgreSQL Flexible Server is deployed in private access mode via delegated subnet
• NSGs are attached to all subnets with deny-by-default Azure platform baselines
• Key Vault network ACLs default to Deny with no bypass (configurable)
• Private endpoints are managed at the composition layer (root stack), not inside modules

Secrets and Keys

• Key Vault soft delete and purge protection are enabled by default
• Optional CMK key can be provisioned in Key Vault for downstream encryption patterns
• CMK creation is gated on private endpoint availability (dependency enforced in root stack)

Data Governance

• Cosmos DB: configurable consistency level, backup type, and retention policy
• PostgreSQL: private access only, TLS enforced, Entra ID authentication
• All data services are accessible only through private endpoints or delegated subnets

Model Governance

• OpenAI model deployments are parameterized (name, model, version, capacity)
• Local authentication disabled on OpenAI — managed identity required
• Quotas configurable per deployment

Logging and Audit

• Diagnostic settings stream logs and metrics to Log Analytics
• Log retention is configurable per workspace
• Policy baseline can enforce allowed locations and deny public exposure on selected services

Policy Controls

• Allowed locations enforcement
• Private endpoint audit policy
• Deny public PaaS access policy
• All policy assignments are configurable and can be disabled

Exit Plan

• Terraform state remains customer-owned
• Resource ownership is fully within customer subscription(s)
• No dependency on external hosted control plane