ABAC (Attribute-Based Access Control)

ABAC extends Stratum’s permission system with attribute-based conditions. While permission delegation controls what tenants can do (feature flags, capability toggles), ABAC controls who can do what to which resources based on attributes of the user, the action, and the resource.

When to Use ABAC

Use case	Permission delegation	ABAC
”Enterprise plan gets SIEM feature”	`features.siem = true`	—
“Only admins can delete users over 90 days old”	—	condition on role + age
”Engineering dept can read classified docs”	—	condition on department + classification
”Lock max_users at 1000 for all children”	`max_users = 1000, LOCKED`	—

Use permissions for on/off feature flags. Use ABAC for conditional, attribute-based rules.

Creating Policies

await stratum.createAbacPolicy(tenantId, {
  name: "admin-delete-old-users",
  resource_type: "user",
  action: "delete",
  effect: "allow",
  conditions: [
    { attribute: "role", operator: "eq", value: "admin" },
    { attribute: "account_age_days", operator: "gt", value: 90 },
  ],
  mode: "INHERITED",   // children inherit this policy
  priority: 10,
});

Condition Operators

Operator	Description	Example
`eq`	Equals	`role eq "admin"`
`neq`	Not equals	`status neq "suspended"`
`in`	Value in array	`dept in ["eng", "product"]`
`not_in`	Value not in array	`tier not_in ["free"]`
`contains`	Array contains value	`tags contains "urgent"`
`gt`	Greater than (numeric)	`level gt 5`
`gte`	Greater than or equal	`clearance gte 3`
`lt`	Less than (numeric)	`risk lt 3`
`lte`	Less than or equal	`age_days lte 30`

All conditions in a policy are AND’d — every condition must match for the policy to apply.

Evaluating Access

const result = await stratum.evaluateAbac(tenantId, {
  subject: { role: "admin", department: "engineering" },
  action: "delete",
  resource: { type: "user", account_age_days: 120 },
});

console.log(result.allowed);        // true
console.log(result.reason);         // "explicit_allow"
console.log(result.matched_policy); // the policy that matched

Evaluation Rules

Deny overrides allow — if any deny policy matches, the request is denied regardless of allow policies
Priority — higher priority policies are evaluated first
Default deny — if no policy matches, the request is denied
Wildcard — use * for resource_type or action to match any value

Hierarchical Inheritance

ABAC policies inherit through the tenant tree using the same modes as permissions:

Root (MSSP)
  └── MSP A
       └── Customer X

LOCKED

A LOCKED policy on the root cannot be overridden by children:

// Root locks down: nobody can delete archived users
await stratum.createAbacPolicy(rootId, {
  name: "no-delete-archived",
  resource_type: "user",
  action: "delete",
  effect: "deny",
  conditions: [{ attribute: "status", operator: "eq", value: "archived" }],
  mode: "LOCKED",
  priority: 100,
});

// MSP A tries to override — this throws AbacPolicyLockedError
await stratum.createAbacPolicy(mspAId, {
  name: "no-delete-archived",
  resource_type: "user",
  action: "delete",
  effect: "allow",
  conditions: [],
});

INHERITED

Children inherit the policy but can override it with their own:

await stratum.createAbacPolicy(rootId, {
  name: "default-read-access",
  resource_type: "document",
  action: "read",
  effect: "allow",
  conditions: [{ attribute: "classification", operator: "lte", value: 3 }],
  mode: "INHERITED",
});

// Customer X can tighten the rule for their own users
await stratum.createAbacPolicy(customerXId, {
  name: "default-read-access",
  resource_type: "document",
  action: "read",
  effect: "allow",
  conditions: [{ attribute: "classification", operator: "lte", value: 1 }],
});

DELEGATED

Children can create their own policies for the same resource/action:

await stratum.createAbacPolicy(rootId, {
  name: "base-write-policy",
  resource_type: "document",
  action: "write",
  effect: "allow",
  conditions: [{ attribute: "role", operator: "in", value: ["admin", "editor"] }],
  mode: "DELEGATED",
});

REST API

Method	Endpoint	Description
`POST`	`/api/v1/tenants/:id/abac-policies`	Create a policy
`GET`	`/api/v1/tenants/:id/abac-policies`	List policies for a tenant
`POST`	`/api/v1/tenants/:id/abac-policies/evaluate`	Evaluate an ABAC request
`DELETE`	`/api/v1/tenants/:id/abac-policies/:policyId`	Delete a policy