Dataverse - Removal of blocked file extensions

let query_frequency = 1h;
let default_attachments = split('ade;adp;app;asa;ashx;asmx;asp;bas;bat;cdx;cer;chm;class;cmd;com;config;cpl;crt;csh;dll;exe;fxp;hlp;hta;htr;htw;ida;idc;idq;inf;ins;isp;its;jar;js;jse;ksh;lnk;mad;maf;mag;mam;maq;mar;mas;mat;mau;mav;maw;mda;mdb;mde;mdt;mdw;mdz;msc;msh;msh1;msh1xml;msh2;msh2xml;mshxml;msi;msp;mst;ops;pcd;pif;prf;prg;printer;pst;reg;rem;scf;scr;sct;shb;shs;shtm;shtml;soap;stm;tmp;url;vb;vbe;vbs;vsmacros;vss;vst;vsw;ws;wsc;wsf;wsh', ";");
DataverseActivity
| where TimeGenerated >= ago(query_frequency)
| where Message == "Update" and EntityName =~ 'organization'
| mv-expand Fields
| where Fields.Name == "blockedattachments"
| extend
    UpdatedAttachments = split(tostring(Fields.Value), ";"),
    CloudAppId = int(32780),
    AccountName = tostring(split(UserId, '@')[0]),
    UPNSuffix = tostring(split(UserId, '@')[1])
| extend RemovedAttachments = set_difference(default_attachments, UpdatedAttachments)
| project
    TimeGenerated,
    UserId,
    ClientIp,
    InstanceUrl,
    RemovedAttachments,
    CloudAppId,
    AccountName,
    UPNSuffix

entityMappings:
- entityType: Account
  fieldMappings:
  - identifier: Name
    columnName: AccountName
  - identifier: UPNSuffix
    columnName: UPNSuffix
- entityType: IP
  fieldMappings:
  - identifier: Address
    columnName: ClientIp
- entityType: CloudApplication
  fieldMappings:
  - identifier: AppId
    columnName: CloudAppId
  - identifier: InstanceName
    columnName: InstanceUrl
queryFrequency: 1h
name: Dataverse - Removal of blocked file extensions
alertDetailsOverride:
  alertDisplayNameFormat: 'Dataverse - Blocked file extension removed in {{InstanceUrl}} '
  alertDescriptionFormat: '{{UserId}} modified environment blocked extensions list. {{UserId}} removed the following extensions {{RemovedAttachments}}.'
kind: Scheduled
tactics:
- DefenseEvasion
triggerThreshold: 0
query: |
  let query_frequency = 1h;
  let default_attachments = split('ade;adp;app;asa;ashx;asmx;asp;bas;bat;cdx;cer;chm;class;cmd;com;config;cpl;crt;csh;dll;exe;fxp;hlp;hta;htr;htw;ida;idc;idq;inf;ins;isp;its;jar;js;jse;ksh;lnk;mad;maf;mag;mam;maq;mar;mas;mat;mau;mav;maw;mda;mdb;mde;mdt;mdw;mdz;msc;msh;msh1;msh1xml;msh2;msh2xml;mshxml;msi;msp;mst;ops;pcd;pif;prf;prg;printer;pst;reg;rem;scf;scr;sct;shb;shs;shtm;shtml;soap;stm;tmp;url;vb;vbe;vbs;vsmacros;vss;vst;vsw;ws;wsc;wsf;wsh', ";");
  DataverseActivity
  | where TimeGenerated >= ago(query_frequency)
  | where Message == "Update" and EntityName =~ 'organization'
  | mv-expand Fields
  | where Fields.Name == "blockedattachments"
  | extend
      UpdatedAttachments = split(tostring(Fields.Value), ";"),
      CloudAppId = int(32780),
      AccountName = tostring(split(UserId, '@')[0]),
      UPNSuffix = tostring(split(UserId, '@')[1])
  | extend RemovedAttachments = set_difference(default_attachments, UpdatedAttachments)
  | project
      TimeGenerated,
      UserId,
      ClientIp,
      InstanceUrl,
      RemovedAttachments,
      CloudAppId,
      AccountName,
      UPNSuffix  
relevantTechniques:
- T1629
triggerOperator: gt
queryPeriod: 1d
eventGroupingSettings:
  aggregationKind: AlertPerResult
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft Business Applications/Analytic Rules/Dataverse - Removal of blocked file extensions.yaml
severity: Medium
status: Available
id: 1b1061be-2595-4492-af6d-1c8a5fc9576d
requiredDataConnectors:
- connectorId: Dataverse
  dataTypes:
  - DataverseActivity
version: 3.2.0
description: Identifies modifications to an environment's blocked file extensions and extracts the removed extension.

{
  "$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/1b1061be-2595-4492-af6d-1c8a5fc9576d')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/1b1061be-2595-4492-af6d-1c8a5fc9576d')]",
      "properties": {
        "alertDetailsOverride": {
          "alertDescriptionFormat": "{{UserId}} modified environment blocked extensions list. {{UserId}} removed the following extensions {{RemovedAttachments}}.",
          "alertDisplayNameFormat": "Dataverse - Blocked file extension removed in {{InstanceUrl}} "
        },
        "alertRuleTemplateName": "1b1061be-2595-4492-af6d-1c8a5fc9576d",
        "customDetails": null,
        "description": "Identifies modifications to an environment's blocked file extensions and extracts the removed extension.",
        "displayName": "Dataverse - Removal of blocked file extensions",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "AccountName",
                "identifier": "Name"
              },
              {
                "columnName": "UPNSuffix",
                "identifier": "UPNSuffix"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "ClientIp",
                "identifier": "Address"
              }
            ]
          },
          {
            "entityType": "CloudApplication",
            "fieldMappings": [
              {
                "columnName": "CloudAppId",
                "identifier": "AppId"
              },
              {
                "columnName": "InstanceUrl",
                "identifier": "InstanceName"
              }
            ]
          }
        ],
        "eventGroupingSettings": {
          "aggregationKind": "AlertPerResult"
        },
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft Business Applications/Analytic Rules/Dataverse - Removal of blocked file extensions.yaml",
        "query": "let query_frequency = 1h;\nlet default_attachments = split('ade;adp;app;asa;ashx;asmx;asp;bas;bat;cdx;cer;chm;class;cmd;com;config;cpl;crt;csh;dll;exe;fxp;hlp;hta;htr;htw;ida;idc;idq;inf;ins;isp;its;jar;js;jse;ksh;lnk;mad;maf;mag;mam;maq;mar;mas;mat;mau;mav;maw;mda;mdb;mde;mdt;mdw;mdz;msc;msh;msh1;msh1xml;msh2;msh2xml;mshxml;msi;msp;mst;ops;pcd;pif;prf;prg;printer;pst;reg;rem;scf;scr;sct;shb;shs;shtm;shtml;soap;stm;tmp;url;vb;vbe;vbs;vsmacros;vss;vst;vsw;ws;wsc;wsf;wsh', \";\");\nDataverseActivity\n| where TimeGenerated >= ago(query_frequency)\n| where Message == \"Update\" and EntityName =~ 'organization'\n| mv-expand Fields\n| where Fields.Name == \"blockedattachments\"\n| extend\n    UpdatedAttachments = split(tostring(Fields.Value), \";\"),\n    CloudAppId = int(32780),\n    AccountName = tostring(split(UserId, '@')[0]),\n    UPNSuffix = tostring(split(UserId, '@')[1])\n| extend RemovedAttachments = set_difference(default_attachments, UpdatedAttachments)\n| project\n    TimeGenerated,\n    UserId,\n    ClientIp,\n    InstanceUrl,\n    RemovedAttachments,\n    CloudAppId,\n    AccountName,\n    UPNSuffix\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "P1D",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "DefenseEvasion"
        ],
        "techniques": null,
        "templateVersion": "3.2.0",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}