Rare and potentially high-risk Office operations | Microsoft Sentinel Analytic Rules

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Id	957cb240-f45d-4491-9ba5-93430a3c08be
Rulename	Rare and potentially high-risk Office operations
Description	Identifies Office operations that are typically rare and can provide capabilities useful to attackers.
Severity	Low
Tactics	Persistence Collection
Techniques	T1098 T1114
Required data connectors	Office365
Kind	Scheduled
Query frequency	1d
Query period	1d
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft%20365/Analytic%20Rules/RareOfficeOperations.yaml
Version	2.0.5
Arm template	957cb240-f45d-4491-9ba5-93430a3c08be.json

KQL

OfficeActivity
| where Operation in~ ( "Add-MailboxPermission", "Add-MailboxFolderPermission", "Set-Mailbox", "New-ManagementRoleAssignment", "New-InboxRule", "Set-InboxRule", "Set-TransportRule")
and not(UserId has_any ('NT AUTHORITY\\SYSTEM (Microsoft.Exchange.ServiceHost)', 'NT AUTHORITY\\SYSTEM (Microsoft.Exchange.AdminApi.NetCore)', 'NT AUTHORITY\\SYSTEM (w3wp)', 'devilfish-applicationaccount') and Operation in~ ( "Add-MailboxPermission", "Set-Mailbox"))
| extend ClientIPOnly = tostring(extract_all(@'\[?(::ffff:)?(?P<IPAddress>(\d+\.\d+\.\d+\.\d+)|[^\]]+)\]?', dynamic(["IPAddress"]), ClientIP)[0])
| extend AccountName = tostring(split(UserId, "@")[0]), AccountUPNSuffix = tostring(split(UserId, "@")[1])

YAML

name: Rare and potentially high-risk Office operations
triggerOperator: gt
query: |
  OfficeActivity
  | where Operation in~ ( "Add-MailboxPermission", "Add-MailboxFolderPermission", "Set-Mailbox", "New-ManagementRoleAssignment", "New-InboxRule", "Set-InboxRule", "Set-TransportRule")
  and not(UserId has_any ('NT AUTHORITY\\SYSTEM (Microsoft.Exchange.ServiceHost)', 'NT AUTHORITY\\SYSTEM (Microsoft.Exchange.AdminApi.NetCore)', 'NT AUTHORITY\\SYSTEM (w3wp)', 'devilfish-applicationaccount') and Operation in~ ( "Add-MailboxPermission", "Set-Mailbox"))
  | extend ClientIPOnly = tostring(extract_all(@'\[?(::ffff:)?(?P<IPAddress>(\d+\.\d+\.\d+\.\d+)|[^\]]+)\]?', dynamic(["IPAddress"]), ClientIP)[0])
  | extend AccountName = tostring(split(UserId, "@")[0]), AccountUPNSuffix = tostring(split(UserId, "@")[1])
queryFrequency: 1d
description: |
  'Identifies Office operations that are typically rare and can provide capabilities useful to attackers.'
id: 957cb240-f45d-4491-9ba5-93430a3c08be
triggerThreshold: 0
queryPeriod: 1d
version: 2.0.5
kind: Scheduled
status: Available
severity: Low
requiredDataConnectors:
- connectorId: Office365
  dataTypes:
  - OfficeActivity
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft%20365/Analytic%20Rules/RareOfficeOperations.yaml
relevantTechniques:
- T1098
- T1114
tactics:
- Persistence
- Collection
entityMappings:
- fieldMappings:
  - identifier: FullName
    columnName: UserId
  - identifier: Name
    columnName: AccountName
  - identifier: UPNSuffix
    columnName: AccountUPNSuffix
  entityType: Account
- fieldMappings:
  - identifier: Address
    columnName: ClientIP
  entityType: IP
- fieldMappings:
  - identifier: AppId
    columnName: AppId
  entityType: CloudApplication

ARM

{
  "$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/957cb240-f45d-4491-9ba5-93430a3c08be')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/957cb240-f45d-4491-9ba5-93430a3c08be')]",
      "properties": {
        "alertRuleTemplateName": "957cb240-f45d-4491-9ba5-93430a3c08be",
        "customDetails": null,
        "description": "'Identifies Office operations that are typically rare and can provide capabilities useful to attackers.'\n",
        "displayName": "Rare and potentially high-risk Office operations",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "UserId",
                "identifier": "FullName"
              },
              {
                "columnName": "AccountName",
                "identifier": "Name"
              },
              {
                "columnName": "AccountUPNSuffix",
                "identifier": "UPNSuffix"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "ClientIP",
                "identifier": "Address"
              }
            ]
          },
          {
            "entityType": "CloudApplication",
            "fieldMappings": [
              {
                "columnName": "AppId",
                "identifier": "AppId"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft%20365/Analytic%20Rules/RareOfficeOperations.yaml",
        "query": "OfficeActivity\n| where Operation in~ ( \"Add-MailboxPermission\", \"Add-MailboxFolderPermission\", \"Set-Mailbox\", \"New-ManagementRoleAssignment\", \"New-InboxRule\", \"Set-InboxRule\", \"Set-TransportRule\")\nand not(UserId has_any ('NT AUTHORITY\\\\SYSTEM (Microsoft.Exchange.ServiceHost)', 'NT AUTHORITY\\\\SYSTEM (Microsoft.Exchange.AdminApi.NetCore)', 'NT AUTHORITY\\\\SYSTEM (w3wp)', 'devilfish-applicationaccount') and Operation in~ ( \"Add-MailboxPermission\", \"Set-Mailbox\"))\n| extend ClientIPOnly = tostring(extract_all(@'\\[?(::ffff:)?(?P<IPAddress>(\\d+\\.\\d+\\.\\d+\\.\\d+)|[^\\]]+)\\]?', dynamic([\"IPAddress\"]), ClientIP)[0])\n| extend AccountName = tostring(split(UserId, \"@\")[0]), AccountUPNSuffix = tostring(split(UserId, \"@\")[1])\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P1D",
        "severity": "Low",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Collection",
          "Persistence"
        ],
        "techniques": [
          "T1098",
          "T1114"
        ],
        "templateVersion": "2.0.5",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}