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'

id: 3ab04acf-e0e7-4f7c-8995-748ab4c848c2
triggerOperator: gt
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft Defender XDR/Analytic Rules/Exfiltration/FilesCopiedToUSBDrives.yaml
requiredDataConnectors:
- dataTypes:
  - DeviceEvents
  - DeviceFileEvents
  connectorId: MicrosoftThreatProtection
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.
severity: High
queryPeriod: 1h
kind: Scheduled
tactics:
- Exfiltration
queryFrequency: 1h
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'  
version: 1.0.0
triggerThreshold: 0
name: Files Copied to USB Drives
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
status: Available
relevantTechniques:
- T1041

{
  "$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"
    }
  ]
}