Cross-tenant Access Settings Organization Inbound Collaboration Settings Changed

// In User & Groups and in Applications, the following "AccessType" values in columns PremodifiedInboundSettings and ModifiedInboundSettings are interpreted accordingly
// When Access Type in premodified inbound settings value was 1 that means that the initial access was allowed. When Access Type in premodified inbound settings value was 2 that means that the initial access was blocked.
// When Access Type in modified inbound settings value is 1 that means that now access is allowed. When Access Type in modified inbound settings value is 2 that means that now access is blocked.
AuditLogs
| where OperationName has "Update a partner cross-tenant access setting"
| mv-apply TargetResource = TargetResources on
  (
      where TargetResource.type =~ "Policy"
      | extend Properties = TargetResource.modifiedProperties
  )
| mv-apply Property = Properties on
  (
      where Property.displayName =~ "b2bCollaborationInbound"
      | extend PremodifiedInboundSettings = trim('"',tostring(Property.oldValue)),
               ModifiedInboundSettings = trim(@'"',tostring(Property.newValue))
  )
| where PremodifiedInboundSettings != ModifiedInboundSettings
| extend InitiatingAppName = tostring(InitiatedBy.app.displayName)
| extend InitiatingAppServicePrincipalId = tostring(InitiatedBy.app.servicePrincipalId)
| extend InitiatingUserPrincipalName = tostring(InitiatedBy.user.userPrincipalName)
| extend InitiatingAadUserId = tostring(InitiatedBy.user.id)
| extend InitiatingIpAddress = tostring(iff(isnotempty(InitiatedBy.user.ipAddress), InitiatedBy.user.ipAddress, InitiatedBy.app.ipAddress))
| extend InitiatingAccountName = tostring(split(InitiatingUserPrincipalName, "@")[0]), InitiatingAccountUPNSuffix = tostring(split(InitiatingUserPrincipalName, "@")[1])

relevantTechniques:
- T1078.004
- T1136.003
- T1087.004
name: Cross-tenant Access Settings Organization Inbound Collaboration Settings Changed
requiredDataConnectors:
- dataTypes:
  - AuditLogs
  connectorId: AzureActiveDirectory
entityMappings:
- fieldMappings:
  - identifier: Name
    columnName: InitiatingAppName
  - identifier: AadUserId
    columnName: InitiatingAppServicePrincipalId
  entityType: Account
- fieldMappings:
  - identifier: FullName
    columnName: InitiatingUserPrincipalName
  - identifier: Name
    columnName: InitiatingAccountName
  - identifier: UPNSuffix
    columnName: InitiatingAccountUPNSuffix
  entityType: Account
- fieldMappings:
  - identifier: AadUserId
    columnName: InitiatingAadUserId
  entityType: Account
- fieldMappings:
  - identifier: Address
    columnName: InitiatingIpAddress
  entityType: IP
triggerThreshold: 0
id: c895c5b9-0fc6-40ce-9830-e8818862f2d5
tactics:
- InitialAccess
- Persistence
- Discovery
version: 1.1.1
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft Entra ID/Analytic Rules/Cross-tenantAccessSettingsOrganizationInboundCollaborationSettingsChanged.yaml
queryPeriod: 2d
kind: Scheduled
queryFrequency: 2d
severity: Medium
status: Available
description: |
    'Organizations are added in the Cross-tenant Access Settings to control communication inbound or outbound for users and applications. This detection notifies when Organization Inbound Collaboration Settings are changed for "Users & Groups" and for "Applications".'
query: |
  // In User & Groups and in Applications, the following "AccessType" values in columns PremodifiedInboundSettings and ModifiedInboundSettings are interpreted accordingly
  // When Access Type in premodified inbound settings value was 1 that means that the initial access was allowed. When Access Type in premodified inbound settings value was 2 that means that the initial access was blocked.
  // When Access Type in modified inbound settings value is 1 that means that now access is allowed. When Access Type in modified inbound settings value is 2 that means that now access is blocked.
  AuditLogs
  | where OperationName has "Update a partner cross-tenant access setting"
  | mv-apply TargetResource = TargetResources on
    (
        where TargetResource.type =~ "Policy"
        | extend Properties = TargetResource.modifiedProperties
    )
  | mv-apply Property = Properties on
    (
        where Property.displayName =~ "b2bCollaborationInbound"
        | extend PremodifiedInboundSettings = trim('"',tostring(Property.oldValue)),
                 ModifiedInboundSettings = trim(@'"',tostring(Property.newValue))
    )
  | where PremodifiedInboundSettings != ModifiedInboundSettings
  | extend InitiatingAppName = tostring(InitiatedBy.app.displayName)
  | extend InitiatingAppServicePrincipalId = tostring(InitiatedBy.app.servicePrincipalId)
  | extend InitiatingUserPrincipalName = tostring(InitiatedBy.user.userPrincipalName)
  | extend InitiatingAadUserId = tostring(InitiatedBy.user.id)
  | extend InitiatingIpAddress = tostring(iff(isnotempty(InitiatedBy.user.ipAddress), InitiatedBy.user.ipAddress, InitiatedBy.app.ipAddress))
  | extend InitiatingAccountName = tostring(split(InitiatingUserPrincipalName, "@")[0]), InitiatingAccountUPNSuffix = tostring(split(InitiatingUserPrincipalName, "@")[1])  
triggerOperator: gt

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2024-01-01-preview",
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/c895c5b9-0fc6-40ce-9830-e8818862f2d5')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/c895c5b9-0fc6-40ce-9830-e8818862f2d5')]",
      "properties": {
        "alertRuleTemplateName": "c895c5b9-0fc6-40ce-9830-e8818862f2d5",
        "customDetails": null,
        "description": "'Organizations are added in the Cross-tenant Access Settings to control communication inbound or outbound for users and applications. This detection notifies when Organization Inbound Collaboration Settings are changed for \"Users & Groups\" and for \"Applications\".'\n",
        "displayName": "Cross-tenant Access Settings Organization Inbound Collaboration Settings Changed",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "InitiatingAppName",
                "identifier": "Name"
              },
              {
                "columnName": "InitiatingAppServicePrincipalId",
                "identifier": "AadUserId"
              }
            ]
          },
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "InitiatingUserPrincipalName",
                "identifier": "FullName"
              },
              {
                "columnName": "InitiatingAccountName",
                "identifier": "Name"
              },
              {
                "columnName": "InitiatingAccountUPNSuffix",
                "identifier": "UPNSuffix"
              }
            ]
          },
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "InitiatingAadUserId",
                "identifier": "AadUserId"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "InitiatingIpAddress",
                "identifier": "Address"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft Entra ID/Analytic Rules/Cross-tenantAccessSettingsOrganizationInboundCollaborationSettingsChanged.yaml",
        "query": "// In User & Groups and in Applications, the following \"AccessType\" values in columns PremodifiedInboundSettings and ModifiedInboundSettings are interpreted accordingly\n// When Access Type in premodified inbound settings value was 1 that means that the initial access was allowed. When Access Type in premodified inbound settings value was 2 that means that the initial access was blocked.\n// When Access Type in modified inbound settings value is 1 that means that now access is allowed. When Access Type in modified inbound settings value is 2 that means that now access is blocked.\nAuditLogs\n| where OperationName has \"Update a partner cross-tenant access setting\"\n| mv-apply TargetResource = TargetResources on\n  (\n      where TargetResource.type =~ \"Policy\"\n      | extend Properties = TargetResource.modifiedProperties\n  )\n| mv-apply Property = Properties on\n  (\n      where Property.displayName =~ \"b2bCollaborationInbound\"\n      | extend PremodifiedInboundSettings = trim('\"',tostring(Property.oldValue)),\n               ModifiedInboundSettings = trim(@'\"',tostring(Property.newValue))\n  )\n| where PremodifiedInboundSettings != ModifiedInboundSettings\n| extend InitiatingAppName = tostring(InitiatedBy.app.displayName)\n| extend InitiatingAppServicePrincipalId = tostring(InitiatedBy.app.servicePrincipalId)\n| extend InitiatingUserPrincipalName = tostring(InitiatedBy.user.userPrincipalName)\n| extend InitiatingAadUserId = tostring(InitiatedBy.user.id)\n| extend InitiatingIpAddress = tostring(iff(isnotempty(InitiatedBy.user.ipAddress), InitiatedBy.user.ipAddress, InitiatedBy.app.ipAddress))\n| extend InitiatingAccountName = tostring(split(InitiatingUserPrincipalName, \"@\")[0]), InitiatingAccountUPNSuffix = tostring(split(InitiatingUserPrincipalName, \"@\")[1])\n",
        "queryFrequency": "P2D",
        "queryPeriod": "P2D",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [
          "T1078.004",
          "T1136.003",
          "T1087.004"
        ],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Discovery",
          "InitialAccess",
          "Persistence"
        ],
        "techniques": [
          "T1078",
          "T1087",
          "T1136"
        ],
        "templateVersion": "1.1.1",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}