GSA Enriched Office 365 - Sharepoint File Transfer Above Threshold

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Id	abd6976d-8f71-4851-98c4-4d086201319c
Rulename	GSA Enriched Office 365 - Sharepoint File Transfer Above Threshold
Description	Identifies Office365 SharePoint file transfers with a distinct folder count above a certain threshold in a 15-minute time period. Please note that entity mapping for arrays is not supported, so when there is a single value in an array, we will pull that value from the array as a single string to populate the entity to support entity mapping features within Sentinel. Additionally, if the array is multivalued, we will input a string to indicate this with a unique hash so that matching will not occur.
Severity	Medium
Tactics	Exfiltration
Techniques	T1020
Required data connectors	AzureActiveDirectory Office365
Kind	Scheduled
Query frequency	15m
Query period	15m
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Global Secure Access/Analytic Rules/Office 365 - sharepoint_file_transfer_folders_above_threshold.yaml
Version	2.0.8
Arm template	abd6976d-8f71-4851-98c4-4d086201319c.json

KQL

let threshold = 5000;
// EnrichedMicrosoft365AuditLogs Query
let EnrichedEvents = EnrichedMicrosoft365AuditLogs
  | where Workload has_any("SharePoint", "OneDrive")
  | where Operation has_any("FileDownloaded", "FileSyncDownloadedFull", "FileSyncUploadedFull", "FileUploaded")
  | extend UserAgent = tostring(AdditionalProperties["UserAgent"])
  | summarize count_distinct_ObjectId = dcount(ObjectId),
              fileslist = make_set(ObjectId, 10000),
              any_UserAgent = any(UserAgent)
    by UserId, ClientIP = ClientIp, bin(TimeGenerated, 15m)
  | where count_distinct_ObjectId >= threshold
  | extend FileSample = iff(array_length(fileslist) == 1, tostring(fileslist[0]),
               strcat("SeeFilesListField_", tostring(hash(tostring(fileslist)))))
  | extend AccountName = tostring(split(UserId, "@")[0]),
           AccountUPNSuffix = tostring(split(UserId, "@")[1]);
// OfficeActivity Query
let OfficeEvents = OfficeActivity
  | where EventSource == "SharePoint"
  | where OfficeWorkload has_any("SharePoint", "OneDrive")
  | where Operation has_any("FileDownloaded", "FileSyncDownloadedFull", "FileSyncUploadedFull", "FileUploaded")
  | summarize count_distinct_ObjectId = dcount(OfficeObjectId),
              fileslist = make_set(OfficeObjectId, 10000),
              any_UserAgent = any(UserAgent)
    by UserId, ClientIP, bin(TimeGenerated, 15m)
  | where count_distinct_ObjectId >= threshold
  | extend FileSample = iff(array_length(fileslist) == 1, tostring(fileslist[0]),
               strcat("SeeFilesListField_", tostring(hash(tostring(fileslist)))))
  | extend AccountName = tostring(split(UserId, "@")[0]),
           AccountUPNSuffix = tostring(split(UserId, "@")[1]);
// Combine Office and Enriched Logs
let CombinedEvents = OfficeEvents
  | union EnrichedEvents
  | summarize arg_min(TimeGenerated, *) by UserId, ClientIP, any_UserAgent;
// Final Output
CombinedEvents
  | extend TransferCount = count_distinct_ObjectId
  | project TimeGenerated, UserId, ClientIP, AccountName, AccountUPNSuffix, FileSample, UserAgent = any_UserAgent, TransferCount, fileslist
  | order by TimeGenerated desc

YAML

query: |
  let threshold = 5000;
  // EnrichedMicrosoft365AuditLogs Query
  let EnrichedEvents = EnrichedMicrosoft365AuditLogs
    | where Workload has_any("SharePoint", "OneDrive")
    | where Operation has_any("FileDownloaded", "FileSyncDownloadedFull", "FileSyncUploadedFull", "FileUploaded")
    | extend UserAgent = tostring(AdditionalProperties["UserAgent"])
    | summarize count_distinct_ObjectId = dcount(ObjectId),
                fileslist = make_set(ObjectId, 10000),
                any_UserAgent = any(UserAgent)
      by UserId, ClientIP = ClientIp, bin(TimeGenerated, 15m)
    | where count_distinct_ObjectId >= threshold
    | extend FileSample = iff(array_length(fileslist) == 1, tostring(fileslist[0]),
                 strcat("SeeFilesListField_", tostring(hash(tostring(fileslist)))))
    | extend AccountName = tostring(split(UserId, "@")[0]),
             AccountUPNSuffix = tostring(split(UserId, "@")[1]);
  // OfficeActivity Query
  let OfficeEvents = OfficeActivity
    | where EventSource == "SharePoint"
    | where OfficeWorkload has_any("SharePoint", "OneDrive")
    | where Operation has_any("FileDownloaded", "FileSyncDownloadedFull", "FileSyncUploadedFull", "FileUploaded")
    | summarize count_distinct_ObjectId = dcount(OfficeObjectId),
                fileslist = make_set(OfficeObjectId, 10000),
                any_UserAgent = any(UserAgent)
      by UserId, ClientIP, bin(TimeGenerated, 15m)
    | where count_distinct_ObjectId >= threshold
    | extend FileSample = iff(array_length(fileslist) == 1, tostring(fileslist[0]),
                 strcat("SeeFilesListField_", tostring(hash(tostring(fileslist)))))
    | extend AccountName = tostring(split(UserId, "@")[0]),
             AccountUPNSuffix = tostring(split(UserId, "@")[1]);
  // Combine Office and Enriched Logs
  let CombinedEvents = OfficeEvents
    | union EnrichedEvents
    | summarize arg_min(TimeGenerated, *) by UserId, ClientIP, any_UserAgent;
  // Final Output
  CombinedEvents
    | extend TransferCount = count_distinct_ObjectId
    | project TimeGenerated, UserId, ClientIP, AccountName, AccountUPNSuffix, FileSample, UserAgent = any_UserAgent, TransferCount, fileslist
    | order by TimeGenerated desc  
relevantTechniques:
- T1020
name: GSA Enriched Office 365 - Sharepoint File Transfer Above Threshold
severity: Medium
triggerThreshold: 0
description: |
    'Identifies Office365 SharePoint file transfers with a distinct folder count above a certain threshold in a 15-minute time period. Please note that entity mapping for arrays is not supported, so when there is a single value in an array, we will pull that value from the array as a single string to populate the entity to support entity mapping features within Sentinel. Additionally, if the array is multivalued, we will input a string to indicate this with a unique hash so that matching will not occur.'
status: Available
incidentConfiguration:
  groupingConfiguration:
    groupByEntities:
    - Account
    lookbackDuration: PT5H
    reopenClosedIncident: false
    enabled: true
    matchingMethod: Selected
  createIncident: true
triggerOperator: gt
tactics:
- Exfiltration
entityMappings:
- fieldMappings:
  - columnName: UserId
    identifier: FullName
  - columnName: AccountName
    identifier: Name
  - columnName: AccountUPNSuffix
    identifier: UPNSuffix
  entityType: Account
- fieldMappings:
  - columnName: ClientIP
    identifier: Address
  entityType: IP
- fieldMappings:
  - columnName: FileSample
    identifier: Name
  entityType: File
customDetails:
  FilesList: fileslist
  TransferCount: TransferCount
requiredDataConnectors:
- connectorId: AzureActiveDirectory
  dataTypes:
  - EnrichedMicrosoft365AuditLogs
- connectorId: Office365
  dataTypes:
  - OfficeActivity (SharePoint)
id: abd6976d-8f71-4851-98c4-4d086201319c
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Global Secure Access/Analytic Rules/Office 365 - sharepoint_file_transfer_folders_above_threshold.yaml
queryPeriod: 15m
queryFrequency: 15m
version: 2.0.8
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/abd6976d-8f71-4851-98c4-4d086201319c')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/abd6976d-8f71-4851-98c4-4d086201319c')]",
      "properties": {
        "alertRuleTemplateName": "abd6976d-8f71-4851-98c4-4d086201319c",
        "customDetails": {
          "FilesList": "fileslist",
          "TransferCount": "TransferCount"
        },
        "description": "'Identifies Office365 SharePoint file transfers with a distinct folder count above a certain threshold in a 15-minute time period. Please note that entity mapping for arrays is not supported, so when there is a single value in an array, we will pull that value from the array as a single string to populate the entity to support entity mapping features within Sentinel. Additionally, if the array is multivalued, we will input a string to indicate this with a unique hash so that matching will not occur.'\n",
        "displayName": "GSA Enriched Office 365 - Sharepoint File Transfer Above Threshold",
        "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": "File",
            "fieldMappings": [
              {
                "columnName": "FileSample",
                "identifier": "Name"
              }
            ]
          }
        ],
        "incidentConfiguration": {
          "createIncident": true,
          "groupingConfiguration": {
            "enabled": true,
            "groupByEntities": [
              "Account"
            ],
            "lookbackDuration": "PT5H",
            "matchingMethod": "Selected",
            "reopenClosedIncident": false
          }
        },
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Global Secure Access/Analytic Rules/Office 365 - sharepoint_file_transfer_folders_above_threshold.yaml",
        "query": "let threshold = 5000;\n// EnrichedMicrosoft365AuditLogs Query\nlet EnrichedEvents = EnrichedMicrosoft365AuditLogs\n  | where Workload has_any(\"SharePoint\", \"OneDrive\")\n  | where Operation has_any(\"FileDownloaded\", \"FileSyncDownloadedFull\", \"FileSyncUploadedFull\", \"FileUploaded\")\n  | extend UserAgent = tostring(AdditionalProperties[\"UserAgent\"])\n  | summarize count_distinct_ObjectId = dcount(ObjectId),\n              fileslist = make_set(ObjectId, 10000),\n              any_UserAgent = any(UserAgent)\n    by UserId, ClientIP = ClientIp, bin(TimeGenerated, 15m)\n  | where count_distinct_ObjectId >= threshold\n  | extend FileSample = iff(array_length(fileslist) == 1, tostring(fileslist[0]),\n               strcat(\"SeeFilesListField_\", tostring(hash(tostring(fileslist)))))\n  | extend AccountName = tostring(split(UserId, \"@\")[0]),\n           AccountUPNSuffix = tostring(split(UserId, \"@\")[1]);\n// OfficeActivity Query\nlet OfficeEvents = OfficeActivity\n  | where EventSource == \"SharePoint\"\n  | where OfficeWorkload has_any(\"SharePoint\", \"OneDrive\")\n  | where Operation has_any(\"FileDownloaded\", \"FileSyncDownloadedFull\", \"FileSyncUploadedFull\", \"FileUploaded\")\n  | summarize count_distinct_ObjectId = dcount(OfficeObjectId),\n              fileslist = make_set(OfficeObjectId, 10000),\n              any_UserAgent = any(UserAgent)\n    by UserId, ClientIP, bin(TimeGenerated, 15m)\n  | where count_distinct_ObjectId >= threshold\n  | extend FileSample = iff(array_length(fileslist) == 1, tostring(fileslist[0]),\n               strcat(\"SeeFilesListField_\", tostring(hash(tostring(fileslist)))))\n  | extend AccountName = tostring(split(UserId, \"@\")[0]),\n           AccountUPNSuffix = tostring(split(UserId, \"@\")[1]);\n// Combine Office and Enriched Logs\nlet CombinedEvents = OfficeEvents\n  | union EnrichedEvents\n  | summarize arg_min(TimeGenerated, *) by UserId, ClientIP, any_UserAgent;\n// Final Output\nCombinedEvents\n  | extend TransferCount = count_distinct_ObjectId\n  | project TimeGenerated, UserId, ClientIP, AccountName, AccountUPNSuffix, FileSample, UserAgent = any_UserAgent, TransferCount, fileslist\n  | order by TimeGenerated desc\n",
        "queryFrequency": "PT15M",
        "queryPeriod": "PT15M",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Exfiltration"
        ],
        "techniques": [
          "T1020"
        ],
        "templateVersion": "2.0.8",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}