Rare and potentially high-risk Office operations

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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 365/Analytic Rules/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

tactics:
- Persistence
- Collection
relevantTechniques:
- T1098
- T1114
id: 957cb240-f45d-4491-9ba5-93430a3c08be
severity: Low
status: Available
name: Rare and potentially high-risk Office operations
requiredDataConnectors:
- connectorId: Office365
  dataTypes:
  - OfficeActivity
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])  
queryPeriod: 1d
entityMappings:
- entityType: Account
  fieldMappings:
  - identifier: FullName
    columnName: UserId
  - identifier: Name
    columnName: AccountName
  - identifier: UPNSuffix
    columnName: AccountUPNSuffix
- entityType: IP
  fieldMappings:
  - identifier: Address
    columnName: ClientIP
- entityType: CloudApplication
  fieldMappings:
  - identifier: AppId
    columnName: AppId
triggerOperator: gt
triggerThreshold: 0
description: |
    'Identifies Office operations that are typically rare and can provide capabilities useful to attackers.'
version: 2.0.5
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft 365/Analytic Rules/RareOfficeOperations.yaml
queryFrequency: 1d
kind: Scheduled

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 365/Analytic Rules/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"
    }
  ]
}