intermediate

Threat Model: Multi-Tenant SaaS

Tenant data, admin roles, API keys, integrations, search and AI retrieval.

webhookUser / BrowserExternal ProviderPublic APIBackendDatabase
UserLLMAgentToolDataDecisionHumanGuardrail

Assets

Tenant datahighly-sensitive

Loss of tenant data harms users and the system’s core promise.

API keysconfidential

Loss of api keys harms users and the system’s core promise.

Administrative authorityconfidential

Loss of administrative authority harms users and the system’s core promise.

Actors and capabilities

ActorTrustStarting capability
Anonymous visitoruntrustedCan send arbitrary public requests.
Authenticated usersemi-trustedCan exercise product APIs within an account or tenant.
Backend servicetrustedCan read and modify scoped production data.
AdministratorprivilegedCan perform exceptional cross-user operations.

Entry points & trust boundaries

Attack surface
public Public API and login

Rate-limit, parse and authenticate at the first boundary.

authenticated Product resources

Every object needs a resource-level authorization decision.

privileged Admin operations

Step-up, separate authorization and audit.

public Webhook

Verify exact provider, body freshness and event identity.

Boundary validation
Browser ┃ TRUST ┃ API
origin where relevant · session/token · shape and limits
API ┃ TRUST ┃ Backend
principal · action · resource authorization
Backend ┃ TRUST ┃ Database
restricted role · tenant scope

Threats

Information DisclosureTenant isolation failureOpen lesson →

A cache, search or retrieval key omits tenant scope.

IMPACT · Compromise of tenant data.
PREVENT · Enforce the boundary-specific control. Limit the responsible identity.
DETECT · Record principal, action and resource.
TamperingOver-privileged integrationOpen lesson →

One API token reaches unrelated tenants or actions.

IMPACT · Compromise of api keys.
PREVENT · Enforce the boundary-specific control. Limit the responsible identity.
DETECT · Record principal, action and resource.
Information DisclosureSilent admin misuseOpen lesson →

A support action lacks an attributable audit record.

IMPACT · Compromise of administrative authority.
PREVENT · Enforce the boundary-specific control. Limit the responsible identity.
DETECT · Record principal, action and resource.

Residual risk & unknowns

Residual risks
  • • Privileged insiders and control-plane compromise remain high-impact.
  • • Business abuse can use technically valid operations.
Explicitly out of scope
  • • Physical facilities and provider-internal controls.