Dataverse - Terminated employee exfiltration to USB drive

id: c5e75cb6-cea0-49c2-a998-da414035aac1
kind: Scheduled
name: Dataverse - Terminated employee exfiltration to USB drive
description: Identifies files downloaded from Dataverse by departing or terminated
  employees which are copied to USB mounted drives.
severity: High
status: Available
requiredDataConnectors:
  - connectorId: Dataverse
    dataTypes:
      - DataverseActivity
  - connectorId: MicrosoftThreatProtection
    dataTypes:
      - DeviceInfo
      - DeviceEvents
      - DeviceFileEvents
queryFrequency: 1h
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - Exfiltration
relevantTechniques:
  - T1052
query: |
  let drive_mount_lookback = 14d;
  let query_frequency = 1h;
  DataverseActivity
  | distinct InstanceUrl
  | join kind=inner (DeviceFileEvents
      | where TimeGenerated >= ago(query_frequency))
      on $left.InstanceUrl == $right.FileOriginUrl
  | join kind=inner (MSBizAppsTerminatedEmployees()) on $left.InitiatingProcessAccountUpn == $right.UserPrincipalName
  | join kind=inner (DeviceEvents
      | where TimeGenerated >= ago(drive_mount_lookback)
      | where ActionType == "UsbDriveMounted"
      | extend DriveLetter = tostring(AdditionalFields.DriveLetter)
      | summarize MountedDriveLetters = make_set(DriveLetter, 26) by DeviceId, DeviceName)
      on DeviceId
  | extend TargetDriveLetter = tostring(split(FolderPath, "\\")[0])
  | where set_has_element(MountedDriveLetters, TargetDriveLetter)
  | join kind=inner (DeviceInfo
      | summarize arg_max(TimeGenerated, DeviceId, PublicIP) by DeviceName)
      on DeviceId
  | project-rename
      UserId = UserPrincipalName
  | summarize LatestEvent = arg_max(TimeGenerated, *), Files = make_set(FileName, 100) by UserId, InstanceUrl
  | extend
      CloudAppId = int(32780),
      AccountName = tostring(split(UserId, '@')[0]),
      UPNSuffix = tostring(split(UserId, '@')[1])
  | project
      LatestEvent,
      UserId,
      PublicIP,
      Files,
      InstanceUrl,
      CloudAppId,
      AccountName,
      UPNSuffix
eventGroupingSettings:
  aggregationKind: AlertPerResult
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: Name
        columnName: AccountName
      - identifier: UPNSuffix
        columnName: UPNSuffix
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: PublicIP
  - entityType: CloudApplication
    fieldMappings:
      - identifier: AppId
        columnName: CloudAppId
      - identifier: InstanceName
        columnName: InstanceUrl
alertDetailsOverride:
  alertDisplayNameFormat: Dataverse - terminated user copied files from {{InstanceUrl}}
    to USB
  alertDescriptionFormat: '{{UserId}} , on the TerminatedUsers watchlist, was found
    to copy files to a USB mounted drive.'
customDetails: {}
version: 3.2.0