Files Copied to USB Drives

let UsbDriveMount = DeviceEvents
| where ActionType=="UsbDriveMounted"
| extend ParsedFields=parse_json(AdditionalFields)
| project DeviceId, DeviceName, DriveLetter=ParsedFields.DriveLetter, MountTime=TimeGenerated,
ProductName=ParsedFields.ProductName,SerialNumber=ParsedFields.SerialNumber,Manufacturer=ParsedFields.Manufacturer
| order by DeviceId asc, MountTime desc;
let FileCreation = DeviceFileEvents
| where InitiatingProcessAccountName != "system"
| where ActionType == "FileCreated"
| where FolderPath !startswith "C:\\"
| where FolderPath !startswith "\\"
| project ReportId,DeviceId,InitiatingProcessAccountDomain,
InitiatingProcessAccountName,InitiatingProcessAccountUpn,
FileName, FolderPath, SHA256, TimeGenerated, SensitivityLabel, IsAzureInfoProtectionApplied
| order by DeviceId asc, TimeGenerated desc;
FileCreation | lookup kind=inner (UsbDriveMount) on DeviceId
| where FolderPath startswith DriveLetter
| where TimeGenerated >= MountTime
| partition hint.strategy=native by ReportId ( top 1 by MountTime )
| order by DeviceId asc, TimeGenerated desc
| extend HostName = iff(DeviceName has '.', substring(DeviceName, 0, indexof(DeviceName, '.')), DeviceName)
| extend DnsDomain = iff(DeviceName has '.', substring(DeviceName, indexof(DeviceName, '.') + 1), "")
| extend FileHashAlgorithm = 'SHA256'

relevantTechniques:
- T1041
name: Files Copied to USB Drives
requiredDataConnectors:
- dataTypes:
  - DeviceEvents
  - DeviceFileEvents
  connectorId: MicrosoftThreatProtection
entityMappings:
- fieldMappings:
  - identifier: FullName
    columnName: DeviceName
  - identifier: HostName
    columnName: HostName
  - identifier: DnsDomain
    columnName: DnsDomain
  entityType: Host
- fieldMappings:
  - identifier: Name
    columnName: FileName
  - identifier: Directory
    columnName: FolderPath
  entityType: File
- fieldMappings:
  - identifier: Algorithm
    columnName: FileHashAlgorithm
  - identifier: Value
    columnName: SHA256
  entityType: FileHash
triggerThreshold: 0
id: 3ab04acf-e0e7-4f7c-8995-748ab4c848c2
tactics:
- Exfiltration
version: 1.0.0
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft Defender XDR/Analytic Rules/Exfiltration/FilesCopiedToUSBDrives.yaml
queryPeriod: 1h
kind: Scheduled
queryFrequency: 1h
severity: High
status: Available
description: |
    This query lists files copied to USB external drives with USB drive information based on FileCreated events associated with most recent USBDriveMount events befor file creations. But be aware that Advanced Hunting is not monitoring all the file types.
query: |
  let UsbDriveMount = DeviceEvents
  | where ActionType=="UsbDriveMounted"
  | extend ParsedFields=parse_json(AdditionalFields)
  | project DeviceId, DeviceName, DriveLetter=ParsedFields.DriveLetter, MountTime=TimeGenerated,
  ProductName=ParsedFields.ProductName,SerialNumber=ParsedFields.SerialNumber,Manufacturer=ParsedFields.Manufacturer
  | order by DeviceId asc, MountTime desc;
  let FileCreation = DeviceFileEvents
  | where InitiatingProcessAccountName != "system"
  | where ActionType == "FileCreated"
  | where FolderPath !startswith "C:\\"
  | where FolderPath !startswith "\\"
  | project ReportId,DeviceId,InitiatingProcessAccountDomain,
  InitiatingProcessAccountName,InitiatingProcessAccountUpn,
  FileName, FolderPath, SHA256, TimeGenerated, SensitivityLabel, IsAzureInfoProtectionApplied
  | order by DeviceId asc, TimeGenerated desc;
  FileCreation | lookup kind=inner (UsbDriveMount) on DeviceId
  | where FolderPath startswith DriveLetter
  | where TimeGenerated >= MountTime
  | partition hint.strategy=native by ReportId ( top 1 by MountTime )
  | order by DeviceId asc, TimeGenerated desc
  | extend HostName = iff(DeviceName has '.', substring(DeviceName, 0, indexof(DeviceName, '.')), DeviceName)
  | extend DnsDomain = iff(DeviceName has '.', substring(DeviceName, indexof(DeviceName, '.') + 1), "")
  | extend FileHashAlgorithm = 'SHA256'  
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/3ab04acf-e0e7-4f7c-8995-748ab4c848c2')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/3ab04acf-e0e7-4f7c-8995-748ab4c848c2')]",
      "properties": {
        "alertRuleTemplateName": "3ab04acf-e0e7-4f7c-8995-748ab4c848c2",
        "customDetails": null,
        "description": "This query lists files copied to USB external drives with USB drive information based on FileCreated events associated with most recent USBDriveMount events befor file creations. But be aware that Advanced Hunting is not monitoring all the file types.\n",
        "displayName": "Files Copied to USB Drives",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "columnName": "DeviceName",
                "identifier": "FullName"
              },
              {
                "columnName": "HostName",
                "identifier": "HostName"
              },
              {
                "columnName": "DnsDomain",
                "identifier": "DnsDomain"
              }
            ]
          },
          {
            "entityType": "File",
            "fieldMappings": [
              {
                "columnName": "FileName",
                "identifier": "Name"
              },
              {
                "columnName": "FolderPath",
                "identifier": "Directory"
              }
            ]
          },
          {
            "entityType": "FileHash",
            "fieldMappings": [
              {
                "columnName": "FileHashAlgorithm",
                "identifier": "Algorithm"
              },
              {
                "columnName": "SHA256",
                "identifier": "Value"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft Defender XDR/Analytic Rules/Exfiltration/FilesCopiedToUSBDrives.yaml",
        "query": "let UsbDriveMount = DeviceEvents\n| where ActionType==\"UsbDriveMounted\"\n| extend ParsedFields=parse_json(AdditionalFields)\n| project DeviceId, DeviceName, DriveLetter=ParsedFields.DriveLetter, MountTime=TimeGenerated,\nProductName=ParsedFields.ProductName,SerialNumber=ParsedFields.SerialNumber,Manufacturer=ParsedFields.Manufacturer\n| order by DeviceId asc, MountTime desc;\nlet FileCreation = DeviceFileEvents\n| where InitiatingProcessAccountName != \"system\"\n| where ActionType == \"FileCreated\"\n| where FolderPath !startswith \"C:\\\\\"\n| where FolderPath !startswith \"\\\\\"\n| project ReportId,DeviceId,InitiatingProcessAccountDomain,\nInitiatingProcessAccountName,InitiatingProcessAccountUpn,\nFileName, FolderPath, SHA256, TimeGenerated, SensitivityLabel, IsAzureInfoProtectionApplied\n| order by DeviceId asc, TimeGenerated desc;\nFileCreation | lookup kind=inner (UsbDriveMount) on DeviceId\n| where FolderPath startswith DriveLetter\n| where TimeGenerated >= MountTime\n| partition hint.strategy=native by ReportId ( top 1 by MountTime )\n| order by DeviceId asc, TimeGenerated desc\n| extend HostName = iff(DeviceName has '.', substring(DeviceName, 0, indexof(DeviceName, '.')), DeviceName)\n| extend DnsDomain = iff(DeviceName has '.', substring(DeviceName, indexof(DeviceName, '.') + 1), \"\")\n| extend FileHashAlgorithm = 'SHA256'\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "PT1H",
        "severity": "High",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Exfiltration"
        ],
        "techniques": [
          "T1041"
        ],
        "templateVersion": "1.0.0",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}