Cisco Umbrella - Connection to Unpopular Website Detected

let domain_lookBack= 14d;
let timeframe = 1d;
let top_million_list = Cisco_Umbrella
| where EventType == "proxylogs"
| where TimeGenerated > ago(domain_lookBack) and TimeGenerated < ago(timeframe)
| extend Hostname = parse_url(UrlOriginal)["Host"]
| summarize count() by tostring(Hostname)
| top 1000000 by count_
| summarize make_list(Hostname);
Cisco_Umbrella
| where EventType == "proxylogs"
| where TimeGenerated > ago(timeframe)
| extend Hostname = parse_url(UrlOriginal)["Host"]
| where Hostname !in (top_million_list)
| extend Message = "Connect to unpopular website (possible malicious payload delivery)"
| project Message, SrcIpAddr, DstIpAddr,UrlOriginal, TimeGenerated

entityMappings:
- entityType: URL
  fieldMappings:
  - identifier: Url
    columnName: UrlOriginal
- entityType: IP
  fieldMappings:
  - identifier: Address
    columnName: SrcIpAddr
name: Cisco Umbrella - Connection to Unpopular Website Detected
tactics:
- CommandAndControl
severity: Medium
triggerThreshold: 0
id: 75297f62-10a8-4fc1-9b2a-12f25c6f05a7
version: 1.1.2
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/CiscoUmbrella/CiscoUmbrellaConnectionToUnpopularWebsiteDetected.yaml
queryFrequency: 1d
triggerOperator: gt
query: |
  let domain_lookBack= 14d;
  let timeframe = 1d;
  let top_million_list = Cisco_Umbrella
  | where EventType == "proxylogs"
  | where TimeGenerated > ago(domain_lookBack) and TimeGenerated < ago(timeframe)
  | extend Hostname = parse_url(UrlOriginal)["Host"]
  | summarize count() by tostring(Hostname)
  | top 1000000 by count_
  | summarize make_list(Hostname);
  Cisco_Umbrella
  | where EventType == "proxylogs"
  | where TimeGenerated > ago(timeframe)
  | extend Hostname = parse_url(UrlOriginal)["Host"]
  | where Hostname !in (top_million_list)
  | extend Message = "Connect to unpopular website (possible malicious payload delivery)"
  | project Message, SrcIpAddr, DstIpAddr,UrlOriginal, TimeGenerated  
description: |
    'Detects first connection to an unpopular website (possible malicious payload delivery).'
requiredDataConnectors:
- connectorId: CiscoUmbrellaDataConnector
  dataTypes:
  - Cisco_Umbrella_proxy_CL
queryPeriod: 14d
kind: Scheduled

{
  "$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/75297f62-10a8-4fc1-9b2a-12f25c6f05a7')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/75297f62-10a8-4fc1-9b2a-12f25c6f05a7')]",
      "properties": {
        "alertRuleTemplateName": "75297f62-10a8-4fc1-9b2a-12f25c6f05a7",
        "customDetails": null,
        "description": "'Detects first connection to an unpopular website (possible malicious payload delivery).'\n",
        "displayName": "Cisco Umbrella - Connection to Unpopular Website Detected",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "URL",
            "fieldMappings": [
              {
                "columnName": "UrlOriginal",
                "identifier": "Url"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "SrcIpAddr",
                "identifier": "Address"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Detections/CiscoUmbrella/CiscoUmbrellaConnectionToUnpopularWebsiteDetected.yaml",
        "query": "let domain_lookBack= 14d;\nlet timeframe = 1d;\nlet top_million_list = Cisco_Umbrella\n| where EventType == \"proxylogs\"\n| where TimeGenerated > ago(domain_lookBack) and TimeGenerated < ago(timeframe)\n| extend Hostname = parse_url(UrlOriginal)[\"Host\"]\n| summarize count() by tostring(Hostname)\n| top 1000000 by count_\n| summarize make_list(Hostname);\nCisco_Umbrella\n| where EventType == \"proxylogs\"\n| where TimeGenerated > ago(timeframe)\n| extend Hostname = parse_url(UrlOriginal)[\"Host\"]\n| where Hostname !in (top_million_list)\n| extend Message = \"Connect to unpopular website (possible malicious payload delivery)\"\n| project Message, SrcIpAddr, DstIpAddr,UrlOriginal, TimeGenerated\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P14D",
        "severity": "Medium",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "CommandAndControl"
        ],
        "templateVersion": "1.1.2",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}