Review guest access to groups using access reviews APIs

The access reviews API in Microsoft Graph enables organizations to audit and attest to the access that identities (also called principals) are assigned to resources in the organization. With B2B collaboration, you can use Microsoft 365 groups to efficiently manage access for guests to resources such as files, notes, calendars, and even Teams conversations. And by using the access reviews API, organizations can periodically attest to principals that have access to such groups and by extension, other resources in the organization.

In this tutorial, you learn how to:

  • Create a recurring access review of Microsoft 365 groups with guests.
  • Investigate the decisions that are applied to access reviews.

Prerequisites

To complete this tutorial, you need the following resources and privileges:

  • A working Microsoft Entra tenant with a Microsoft Entra ID P2 or Microsoft Entra ID Governance license enabled.
  • A test guest and a test Microsoft 365 group in your tenant. The guest should be a member of the Microsoft 365 group.
  • Sign in to an API client such as Graph Explorer to call Microsoft Graph with an account that has at least the Identity Governance Administrator role.
  • Grant yourself the following delegated permissions: AccessReview.ReadWrite.All.

Step 1: Create an access review for all Microsoft 365 groups with guests

The following access review series uses following settings:

  • It's a recurring access review and reviewed quarterly.
  • The group owners are the decision makers.
  • The review scope is limited to only Microsoft 365 groups with guests.
  • It defines a user as the fallback reviewer who can review the access in case the group doesn't have any owners assigned.
  • autoApplyDecisionsEnabled is set to true. In this case, decisions are applied automatically once the reviewer completes the access review or the access review duration ends. If not enabled, a user must apply the decisions manually after the review completes.
  • applyActions is set to removeAccessApplyAction. This action removes denied guests from the group. The guest can still sign in to your tenant, but won't be members of the group or have the access privileges that are granted through the group.

Request

In this call, replace the following values:

  • c9a5aff7-9298-4d71-adab-0a222e0a05e4 with the ID of the fallback reviewer.
  • Value of startDate with today's date and value of endDate with a date one year from the start date.
POST https://graph.microsoft.com/v1.0/identityGovernance/accessReviews/definitions
Content-type: application/json

{
    "displayName": "Guest access to marketing group",
    "scope": {
        "@odata.type": "#microsoft.graph.accessReviewQueryScope",
        "query": "./members/microsoft.graph.user/?$count=true&$filter=(userType eq 'Guest')",
        "queryType": "MicrosoftGraph"
    },
    "instanceEnumerationScope": {
        "@odata.type": "#microsoft.graph.accessReviewQueryScope",
        "query": "/v1.0/groups?$filter=(groupTypes/any(c:c+eq+'Unified'))&$count=true",
        "queryType": "MicrosoftGraph",
        "queryRoot": null
    },
    "reviewers": [
        {
            "query": "./owners",
            "queryType": "MicrosoftGraph",
            "queryRoot": null
        }
    ],
    "fallbackReviewers": [
        {
            "query": "/users/c9a5aff7-9298-4d71-adab-0a222e0a05e4",
            "queryType": "MicrosoftGraph"
        }
    ],
    "settings": {
        "mailNotificationsEnabled": true,
        "reminderNotificationsEnabled": true,
        "justificationRequiredOnApproval": true,
        "defaultDecisionEnabled": true,
        "defaultDecision": "Deny",
        "instanceDurationInDays": 3,
        "autoApplyDecisionsEnabled": true,
        "recommendationsEnabled": true,
        "recommendationLookBackDuration": "P30D",
        "decisionHistoriesForReviewersEnabled": false,
        "recurrence": {
            "pattern": {
                "type": "absoluteMonthly",
                "interval": 3,
                "month": 0,
                "dayOfMonth": 0,
                "daysOfWeek": [],
                "firstDayOfWeek": "sunday",
                "index": "first"
            },
            "range": {
                "type": "endDate",
                "numberOfOccurrences": 0,
                "recurrenceTimeZone": null,
                "startDate": "2024-03-21",
                "endDate": "2025-03-21"
            }
        },
        "applyActions": [
            {
                "@odata.type": "#microsoft.graph.removeAccessApplyAction"
            }
        ]
    }
}

Response

Note: The response object shown here might be shortened for readability.

HTTP/1.1 201 Created
Content-type: application/json

{
    "@odata.context": "https://graph.microsoft.com/v1.0/$metadata#identityGovernance/accessReviews/definitions/$entity",
    "id": "c22ae540-b89a-4d24-bac0-4ef35e6591ea",
    "displayName": "Guest access to marketing group",
    "createdDateTime": null,
    "lastModifiedDateTime": null,
    "status": "NotStarted",
    "descriptionForAdmins": null,
    "descriptionForReviewers": null,
    "scope": {
        "@odata.type": "#microsoft.graph.accessReviewQueryScope",
        "query": "./members/microsoft.graph.user/?$count=true&$filter=(userType eq 'Guest')",
        "queryType": "MicrosoftGraph",
        "queryRoot": null
    },
    "instanceEnumerationScope": {
        "@odata.type": "#microsoft.graph.accessReviewQueryScope",
        "query": "/groups?$filter=(groupTypes/any(c:c+eq+'Unified'))&$count=true",
        "queryType": "MicrosoftGraph",
        "queryRoot": null
    },
    "reviewers": [
        {
            "query": "./owners",
            "queryType": "MicrosoftGraph",
            "queryRoot": null
        }
    ],
    "fallbackReviewers": [
        {
            "query": "/users/c9a5aff7-9298-4d71-adab-0a222e0a05e4",
            "queryType": "MicrosoftGraph",
            "queryRoot": null
        }
    ],
    "settings": {
        "mailNotificationsEnabled": true,
        "reminderNotificationsEnabled": true,
        "justificationRequiredOnApproval": true,
        "defaultDecisionEnabled": true,
        "defaultDecision": "Deny",
        "instanceDurationInDays": 3,
        "autoApplyDecisionsEnabled": true,
        "recommendationsEnabled": true,
        "recommendationLookBackDuration": "P30D",
        "decisionHistoriesForReviewersEnabled": false,
        "recurrence": {
            "pattern": {
                "type": "absoluteMonthly",
                "interval": 3,
                "month": 0,
                "dayOfMonth": 0,
                "daysOfWeek": [],
                "firstDayOfWeek": "sunday",
                "index": "first"
            },
            "range": {
                "type": "endDate",
                "numberOfOccurrences": 0,
                "recurrenceTimeZone": null,
                "startDate": "2024-03-21",
                "endDate": "2025-03-21"
            }
        },
        "applyActions": [
            {
                "@odata.type": "#microsoft.graph.removeAccessApplyAction"
            }
        ],
        "recommendationInsightSettings": []
    },
    "stageSettings": [],
    "additionalNotificationRecipients": []
}

Step 2: List instances of the access review

The following query lists all instances of the access review definition. If there are more than one Microsoft 365 groups with guests in your tenant, this request returns one instance for every Microsoft 365 group with guests.

Request

GET https://graph.microsoft.com/v1.0/identityGovernance/accessReviews/definitions/c22ae540-b89a-4d24-bac0-4ef35e6591ea/instances

Response

In this response, the scope includes the test group because it has a guest. In this response, the access review instance is currently InProgress. Because it's a quarterly review, a new review instance is created automatically every three months and the reviewers can apply new decisions.

Note: The response object shown here might be shortened for readability.

HTTP/1.1 200 OK
Content-type: application/json

{
    "@odata.context": "https://graph.microsoft.com/v1.0/$metadata#identityGovernance/accessReviews/definitions('c22ae540-b89a-4d24-bac0-4ef35e6591ea')/instances",
    "value": [
        {
            "id": "6392b1a7-9c25-4844-83e5-34e23c88e16a",
            "startDateTime": "2024-03-21T17:00:36.96Z",
            "endDateTime": "2024-03-24T17:00:36.96Z",
            "status": "InProgress",
            "scope": {
                "query": "/groups/59ab642a-2776-4e32-9b68-9ff7a47b7f6a/members/microsoft.graph.user/?$count=true&$filter=(userType eq 'Guest')",
                "queryType": "MicrosoftGraph"
            }
        }
    ]
}

Step 3: Get decisions

Get the decisions taken for the instance of an access review. In a quarterly review like this one, and as long as the access review is still active:

  • Every three months a new review instance is created.
  • Reviewers are required to apply new decisions for new instances.

Request

GET https://graph.microsoft.com/v1.0/identityGovernance/accessReviews/definitions/c22ae540-b89a-4d24-bac0-4ef35e6591ea/instances/6392b1a7-9c25-4844-83e5-34e23c88e16a/decisions

Response

The following response shows the decision taken for the instance of the review.

Note: The response object shown here might be shortened for readability.

HTTP/1.1 200 OK
Content-type: application/json

{
    "@odata.context": "https://graph.microsoft.com/v1.0/$metadata#identityGovernance/accessReviews/definitions('c22ae540-b89a-4d24-bac0-4ef35e6591ea')/instances('6392b1a7-9c25-4844-83e5-34e23c88e16a')/decisions",
    "@odata.count": 1,
    "value": [
        {
            "id": "0e76ee07-b4c6-469e-bc9d-e73fc9a8d660",
            "accessReviewId": "6392b1a7-9c25-4844-83e5-34e23c88e16a",
            "reviewedDateTime": "2021-02-10T17:06:26.147Z",
            "decision": "Approve",
            "justification": "",
            "appliedDateTime": null,
            "applyResult": "New",
            "recommendation": "Deny",
            "reviewedBy": {
                "id": "00000000-0000-0000-0000-000000000000",
                "displayName": "AAD Access Reviews",
                "userPrincipalName": "AAD Access Reviews"
            },
            "appliedBy": {
                "id": "00000000-0000-0000-0000-000000000000",
                "displayName": "",
                "userPrincipalName": ""
            },
            "target": {
                "@odata.type": "#microsoft.graph.accessReviewInstanceDecisionItemUserTarget",
                "userId": "baf1b0a0-1f9a-4a56-9884-6a30824f8d20",
                "userDisplayName": "John Doe (Tailspin Toys)",
                "userPrincipalName": "john@tailspintoys.com"
            },
            "principal": {
                "@odata.type": "#microsoft.graph.userIdentity",
                "id": "baf1b0a0-1f9a-4a56-9884-6a30824f8d20",
                "displayName": "John Doe (Tailspin Toys)",
                "userPrincipalName": "john@tailspintoys.com"
            }
        }
    ]
}

Step 4: Clean up resources

In this step, you delete the access review definition. Since the access review schedule definition is the blueprint for the access review, deleting the definition removes the related settings, instances, and decisions. The request returns a 204 No Content response.

DELETE https://graph.microsoft.com/v1.0/identityGovernance/accessReviews/definitions/c22ae540-b89a-4d24-bac0-4ef35e6591ea