Cisco Umbrella - Request to blocklisted file type

let file_ext_blocklist = dynamic(['.ps1', '.vbs', '.bat', '.scr']);
let lbtime = 10m;
Cisco_Umbrella
| where TimeGenerated > ago(lbtime)
| where EventType == 'proxylogs'
| where DvcAction =~ 'Allowed'
| extend file_ext = extract(@'.*(\.\w+)$', 1, UrlOriginal)
| extend Filename = extract(@'.*\/*\/(.*\.\w+)$', 1, UrlOriginal)
| where file_ext in (file_ext_blocklist)
| project TimeGenerated, SrcIpAddr, Identities, Filename

name: Cisco Umbrella - Request to blocklisted file type
requiredDataConnectors:
- dataTypes:
  - Cisco_Umbrella_proxy_CL
  connectorId: CiscoUmbrellaDataConnector
id: de58ee9e-b229-4252-8537-41a4c2f4045e
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/CiscoUmbrella/CiscoUmbrellaRequestBlocklistedFileType.yaml
entityMappings:
- fieldMappings:
  - identifier: FullName
    columnName: Identities
  entityType: Account
- fieldMappings:
  - identifier: Address
    columnName: SrcIpAddr
  entityType: IP
queryPeriod: 10m
kind: Scheduled
version: 1.0.1
description: |
  'Detects request to potentially harmful file types (.ps1, .bat, .vbs, etc.).'
triggerOperator: gt
tactics:
- InitialAccess
query: |
  let file_ext_blocklist = dynamic(['.ps1', '.vbs', '.bat', '.scr']);
  let lbtime = 10m;
  Cisco_Umbrella
  | where TimeGenerated > ago(lbtime)
  | where EventType == 'proxylogs'
  | where DvcAction =~ 'Allowed'
  | extend file_ext = extract(@'.*(\.\w+)$', 1, UrlOriginal)
  | extend Filename = extract(@'.*\/*\/(.*\.\w+)$', 1, UrlOriginal)
  | where file_ext in (file_ext_blocklist)
  | project TimeGenerated, SrcIpAddr, Identities, Filename
severity: Medium
queryFrequency: 10m
triggerThreshold: 0

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2024-01-01-preview",
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/de58ee9e-b229-4252-8537-41a4c2f4045e')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/de58ee9e-b229-4252-8537-41a4c2f4045e')]",
      "properties": {
        "alertRuleTemplateName": "de58ee9e-b229-4252-8537-41a4c2f4045e",
        "customDetails": null,
        "description": "'Detects request to potentially harmful file types (.ps1, .bat, .vbs, etc.).'\n",
        "displayName": "Cisco Umbrella - Request to blocklisted file type",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "Identities",
                "identifier": "FullName"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "SrcIpAddr",
                "identifier": "Address"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Detections/CiscoUmbrella/CiscoUmbrellaRequestBlocklistedFileType.yaml",
        "query": "let file_ext_blocklist = dynamic(['.ps1', '.vbs', '.bat', '.scr']);\nlet lbtime = 10m;\nCisco_Umbrella\n| where TimeGenerated > ago(lbtime)\n| where EventType == 'proxylogs'\n| where DvcAction =~ 'Allowed'\n| extend file_ext = extract(@'.*(\\.\\w+)$', 1, UrlOriginal)\n| extend Filename = extract(@'.*\\/*\\/(.*\\.\\w+)$', 1, UrlOriginal)\n| where file_ext in (file_ext_blocklist)\n| project TimeGenerated, SrcIpAddr, Identities, Filename\n",
        "queryFrequency": "PT10M",
        "queryPeriod": "PT10M",
        "severity": "Medium",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "InitialAccess"
        ],
        "templateVersion": "1.0.1",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}