Rare and potentially high-risk Office operations

id: 957cb240-f45d-4491-9ba5-93430a3c08be
name: Rare and potentially high-risk Office operations
description: |
  'Identifies Office operations that are typically rare and can provide capabilities useful to attackers.'
severity: Low
status: Available
requiredDataConnectors:
  - connectorId: Office365
    dataTypes:
      - OfficeActivity
queryFrequency: 1d
queryPeriod: 1d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - Persistence
  - Collection
relevantTechniques:
  - T1098
  - T1114
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])
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
version: 2.0.5
kind: Scheduled