Office ASR rule triggered from browser spawned office process.

// Add your own browsers here as well. 
let browsers = dynamic(["iexplore.exe", "chrome.exe", "firefox.exe", "msedge.exe"]);
DeviceEvents
| where ActionType contains "Office"
| where InitiatingProcessFileName in~ (browsers) or InitiatingProcessParentFileName in~ (browsers)
// Ignore docx, xlsx and pptx files. These don't contain macros.
| where not(FileName endswith ".docx" or FileName endswith ".xlsx" or FileName endswith ".pptx")

triggerOperator: gt
id: 30580043-2451-4d35-b49f-065728529f4a
queryFrequency: 5m
entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: AccountSid
    identifier: Sid
  - columnName: AccountName
    identifier: Name
  - columnName: AccountDomain
    identifier: NTDomain
- entityType: Host
  fieldMappings:
  - columnName: DeviceName
    identifier: FullName
- entityType: Process
  fieldMappings:
  - columnName: ProcessCommandLine
    identifier: CommandLine
requiredDataConnectors:
- dataTypes:
  - DeviceEvents
  connectorId: MicrosoftThreatProtection
severity: Medium
triggerThreshold: 0
kind: Scheduled
status: Available
queryPeriod: 5m
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/FalconFriday/Analytic Rules/OfficeASRFromBrowser.yaml
query: |
  // Add your own browsers here as well. 
  let browsers = dynamic(["iexplore.exe", "chrome.exe", "firefox.exe", "msedge.exe"]);
  DeviceEvents
  | where ActionType contains "Office"
  | where InitiatingProcessFileName in~ (browsers) or InitiatingProcessParentFileName in~ (browsers)
  // Ignore docx, xlsx and pptx files. These don't contain macros.
  | where not(FileName endswith ".docx" or FileName endswith ".xlsx" or FileName endswith ".pptx")  
description: |
  The attacker sends a spearphishing email to a user. The email contains a link which points to a website that eventually 
  presents the user a download of an MS Office document. This document contains a malicious macro. The macro triggers one of the ASR rules. 
  This detection looks for Office ASR violations triggered by an Office document opened from a browser.
  Note: be aware that you need to have the proper ASR rules enabled for this detection to work.   
name: Office ASR rule triggered from browser spawned office process.
relevantTechniques:
- T1566.002
tactics:
- InitialAccess
version: 1.0.0

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/30580043-2451-4d35-b49f-065728529f4a')]",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/30580043-2451-4d35-b49f-065728529f4a')]",
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules",
      "kind": "Scheduled",
      "apiVersion": "2022-11-01",
      "properties": {
        "displayName": "Office ASR rule triggered from browser spawned office process.",
        "description": "The attacker sends a spearphishing email to a user. The email contains a link which points to a website that eventually \npresents the user a download of an MS Office document. This document contains a malicious macro. The macro triggers one of the ASR rules. \nThis detection looks for Office ASR violations triggered by an Office document opened from a browser.\nNote: be aware that you need to have the proper ASR rules enabled for this detection to work. \n",
        "severity": "Medium",
        "enabled": true,
        "query": "// Add your own browsers here as well. \nlet browsers = dynamic([\"iexplore.exe\", \"chrome.exe\", \"firefox.exe\", \"msedge.exe\"]);\nDeviceEvents\n| where ActionType contains \"Office\"\n| where InitiatingProcessFileName in~ (browsers) or InitiatingProcessParentFileName in~ (browsers)\n// Ignore docx, xlsx and pptx files. These don't contain macros.\n| where not(FileName endswith \".docx\" or FileName endswith \".xlsx\" or FileName endswith \".pptx\")\n",
        "queryFrequency": "PT5M",
        "queryPeriod": "PT5M",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0,
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "InitialAccess"
        ],
        "techniques": [
          "T1566.002"
        ],
        "alertRuleTemplateName": "30580043-2451-4d35-b49f-065728529f4a",
        "customDetails": null,
        "entityMappings": [
          {
            "fieldMappings": [
              {
                "identifier": "Sid",
                "columnName": "AccountSid"
              },
              {
                "identifier": "Name",
                "columnName": "AccountName"
              },
              {
                "identifier": "NTDomain",
                "columnName": "AccountDomain"
              }
            ],
            "entityType": "Account"
          },
          {
            "fieldMappings": [
              {
                "identifier": "FullName",
                "columnName": "DeviceName"
              }
            ],
            "entityType": "Host"
          },
          {
            "fieldMappings": [
              {
                "identifier": "CommandLine",
                "columnName": "ProcessCommandLine"
              }
            ],
            "entityType": "Process"
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/FalconFriday/Analytic Rules/OfficeASRFromBrowser.yaml",
        "templateVersion": "1.0.0",
        "status": "Available"
      }
    }
  ]
}