Exes with double file extension and access summary

let known_ext = dynamic(["lnk", "log", "option", "config", "manifest", "partial"]);
let excluded_users = dynamic(["app@sharepoint"]);
EnrichedMicrosoft365AuditLogs
| where RecordType == "SharePointFileOperation" and isnotempty(ObjectId)
| where ObjectId has ".exe." 
    and not(ObjectId endswith ".lnk") 
    and not(ObjectId endswith ".log") 
    and not(ObjectId endswith ".option") 
    and not(ObjectId endswith ".config") 
    and not(ObjectId endswith ".manifest") 
    and not(ObjectId endswith ".partial")
| extend Extension = extract("[^.]*\\.[^.]*$", 0, ObjectId)
| extend SourceFileName = tostring(parse_json(tostring(AdditionalProperties)).SourceFileName)
| join kind=leftouter (
    EnrichedMicrosoft365AuditLogs
    | where RecordType == "SharePointFileOperation" and (Operation == "FileDownloaded" or Operation == "FileAccessed")
    | where not(ObjectId endswith ".lnk") 
        and not(ObjectId endswith ".log") 
        and not(ObjectId endswith ".option") 
        and not(ObjectId endswith ".config") 
        and not(ObjectId endswith ".manifest") 
        and not(ObjectId endswith ".partial")
) on ObjectId
| where UserId1 !in (excluded_users)
| extend userBag = bag_pack("UserId", UserId1, "ClientIp", ClientIp1)
| summarize make_set(UserId1, 10000), userBag = make_bag(userBag), UploadTime = max(TimeGenerated) by UserId, ObjectId, SourceFileName, Extension
| extend NumberOfUsers = array_length(bag_keys(userBag))
| project UploadTime, Uploader = UserId, FileLocation = ObjectId, FileName = SourceFileName, AccessedBy = userBag, Extension, NumberOfUsers
| extend UploaderName = tostring(split(Uploader, "@")[0]), UploaderUPNSuffix = tostring(split(Uploader, "@")[1])

OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Global Secure Access/Hunting Queries/double_file_ext_exes.yaml
name: Exes with double file extension and access summary
entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: UploaderName
    identifier: Name
  - columnName: UploaderUPNSuffix
    identifier: UPNSuffix
tactics:
- DefenseEvasion
version: 2.0.1
description: |
  'Provides a summary of executable files with double file extensions in SharePoint 
   and the users and IP addresses that have accessed them.'  
requiredDataConnectors:
- dataTypes:
  - EnrichedMicrosoft365AuditLogs
  connectorId: AzureActiveDirectory
kind: Scheduled
query: |
  let known_ext = dynamic(["lnk", "log", "option", "config", "manifest", "partial"]);
  let excluded_users = dynamic(["app@sharepoint"]);
  EnrichedMicrosoft365AuditLogs
  | where RecordType == "SharePointFileOperation" and isnotempty(ObjectId)
  | where ObjectId has ".exe." 
      and not(ObjectId endswith ".lnk") 
      and not(ObjectId endswith ".log") 
      and not(ObjectId endswith ".option") 
      and not(ObjectId endswith ".config") 
      and not(ObjectId endswith ".manifest") 
      and not(ObjectId endswith ".partial")
  | extend Extension = extract("[^.]*\\.[^.]*$", 0, ObjectId)
  | extend SourceFileName = tostring(parse_json(tostring(AdditionalProperties)).SourceFileName)
  | join kind=leftouter (
      EnrichedMicrosoft365AuditLogs
      | where RecordType == "SharePointFileOperation" and (Operation == "FileDownloaded" or Operation == "FileAccessed")
      | where not(ObjectId endswith ".lnk") 
          and not(ObjectId endswith ".log") 
          and not(ObjectId endswith ".option") 
          and not(ObjectId endswith ".config") 
          and not(ObjectId endswith ".manifest") 
          and not(ObjectId endswith ".partial")
  ) on ObjectId
  | where UserId1 !in (excluded_users)
  | extend userBag = bag_pack("UserId", UserId1, "ClientIp", ClientIp1)
  | summarize make_set(UserId1, 10000), userBag = make_bag(userBag), UploadTime = max(TimeGenerated) by UserId, ObjectId, SourceFileName, Extension
  | extend NumberOfUsers = array_length(bag_keys(userBag))
  | project UploadTime, Uploader = UserId, FileLocation = ObjectId, FileName = SourceFileName, AccessedBy = userBag, Extension, NumberOfUsers
  | extend UploaderName = tostring(split(Uploader, "@")[0]), UploaderUPNSuffix = tostring(split(Uploader, "@")[1])  
relevantTechniques:
- T1036
id: d12580c2-1474-4125-a8a3-553f50d91215

{
  "$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/d12580c2-1474-4125-a8a3-553f50d91215')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/d12580c2-1474-4125-a8a3-553f50d91215')]",
      "properties": {
        "alertRuleTemplateName": "d12580c2-1474-4125-a8a3-553f50d91215",
        "customDetails": null,
        "description": "'Provides a summary of executable files with double file extensions in SharePoint \n and the users and IP addresses that have accessed them.'\n",
        "displayName": "Exes with double file extension and access summary",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "UploaderName",
                "identifier": "Name"
              },
              {
                "columnName": "UploaderUPNSuffix",
                "identifier": "UPNSuffix"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Global Secure Access/Hunting Queries/double_file_ext_exes.yaml",
        "query": "let known_ext = dynamic([\"lnk\", \"log\", \"option\", \"config\", \"manifest\", \"partial\"]);\nlet excluded_users = dynamic([\"app@sharepoint\"]);\nEnrichedMicrosoft365AuditLogs\n| where RecordType == \"SharePointFileOperation\" and isnotempty(ObjectId)\n| where ObjectId has \".exe.\" \n    and not(ObjectId endswith \".lnk\") \n    and not(ObjectId endswith \".log\") \n    and not(ObjectId endswith \".option\") \n    and not(ObjectId endswith \".config\") \n    and not(ObjectId endswith \".manifest\") \n    and not(ObjectId endswith \".partial\")\n| extend Extension = extract(\"[^.]*\\\\.[^.]*$\", 0, ObjectId)\n| extend SourceFileName = tostring(parse_json(tostring(AdditionalProperties)).SourceFileName)\n| join kind=leftouter (\n    EnrichedMicrosoft365AuditLogs\n    | where RecordType == \"SharePointFileOperation\" and (Operation == \"FileDownloaded\" or Operation == \"FileAccessed\")\n    | where not(ObjectId endswith \".lnk\") \n        and not(ObjectId endswith \".log\") \n        and not(ObjectId endswith \".option\") \n        and not(ObjectId endswith \".config\") \n        and not(ObjectId endswith \".manifest\") \n        and not(ObjectId endswith \".partial\")\n) on ObjectId\n| where UserId1 !in (excluded_users)\n| extend userBag = bag_pack(\"UserId\", UserId1, \"ClientIp\", ClientIp1)\n| summarize make_set(UserId1, 10000), userBag = make_bag(userBag), UploadTime = max(TimeGenerated) by UserId, ObjectId, SourceFileName, Extension\n| extend NumberOfUsers = array_length(bag_keys(userBag))\n| project UploadTime, Uploader = UserId, FileLocation = ObjectId, FileName = SourceFileName, AccessedBy = userBag, Extension, NumberOfUsers\n| extend UploaderName = tostring(split(Uploader, \"@\")[0]), UploaderUPNSuffix = tostring(split(Uploader, \"@\")[1])\n",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "DefenseEvasion"
        ],
        "techniques": [
          "T1036"
        ],
        "templateVersion": "2.0.1"
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}