Cisco Umbrella - Rare User Agent Detected

let lookBack = 14d;
let timeframe = 1d;
let user_agents_list = Cisco_Umbrella
| where EventType == "proxylogs"
| where TimeGenerated > ago(lookBack) and TimeGenerated < ago(timeframe)
| summarize count() by HttpUserAgentOriginal
| summarize make_list(HttpUserAgentOriginal);
Cisco_Umbrella
| where EventType == "proxylogs"
| where TimeGenerated > ago(timeframe)
| where HttpUserAgentOriginal !in (user_agents_list)
| extend Message = "Rare User Agent"
| project Message, SrcIpAddr, DstIpAddr, UrlOriginal, TimeGenerated, HttpUserAgentOriginal
| extend IPCustomEntity = SrcIpAddr, UrlCustomEntity = UrlOriginal

kind: Scheduled
triggerOperator: gt
queryFrequency: 1d
name: Cisco Umbrella - Rare User Agent Detected
queryPeriod: 14d
id: 8c8de3fa-6425-4623-9cd9-45de1dd0569a
description: |
    'Rule helps to detect a rare user-agents indicating web browsing activity by an unusual process other than a web browser.'
severity: Medium
query: |
  let lookBack = 14d;
  let timeframe = 1d;
  let user_agents_list = Cisco_Umbrella
  | where EventType == "proxylogs"
  | where TimeGenerated > ago(lookBack) and TimeGenerated < ago(timeframe)
  | summarize count() by HttpUserAgentOriginal
  | summarize make_list(HttpUserAgentOriginal);
  Cisco_Umbrella
  | where EventType == "proxylogs"
  | where TimeGenerated > ago(timeframe)
  | where HttpUserAgentOriginal !in (user_agents_list)
  | extend Message = "Rare User Agent"
  | project Message, SrcIpAddr, DstIpAddr, UrlOriginal, TimeGenerated, HttpUserAgentOriginal
  | extend IPCustomEntity = SrcIpAddr, UrlCustomEntity = UrlOriginal  
version: 1.1.1
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/CiscoUmbrella/CiscoUmbrellaRareUserAgentDetected.yaml
entityMappings:
- entityType: URL
  fieldMappings:
  - identifier: Url
    columnName: UrlCustomEntity
- entityType: IP
  fieldMappings:
  - identifier: Address
    columnName: IPCustomEntity
requiredDataConnectors:
- connectorId: CiscoUmbrellaDataConnector
  dataTypes:
  - Cisco_Umbrella_proxy_CL
tactics:
- CommandAndControl
triggerThreshold: 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/8c8de3fa-6425-4623-9cd9-45de1dd0569a')]",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/8c8de3fa-6425-4623-9cd9-45de1dd0569a')]",
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules",
      "kind": "Scheduled",
      "apiVersion": "2022-11-01-preview",
      "properties": {
        "displayName": "Cisco Umbrella - Rare User Agent Detected",
        "description": "'Rule helps to detect a rare user-agents indicating web browsing activity by an unusual process other than a web browser.'\n",
        "severity": "Medium",
        "enabled": true,
        "query": "let lookBack = 14d;\nlet timeframe = 1d;\nlet user_agents_list = Cisco_Umbrella\n| where EventType == \"proxylogs\"\n| where TimeGenerated > ago(lookBack) and TimeGenerated < ago(timeframe)\n| summarize count() by HttpUserAgentOriginal\n| summarize make_list(HttpUserAgentOriginal);\nCisco_Umbrella\n| where EventType == \"proxylogs\"\n| where TimeGenerated > ago(timeframe)\n| where HttpUserAgentOriginal !in (user_agents_list)\n| extend Message = \"Rare User Agent\"\n| project Message, SrcIpAddr, DstIpAddr, UrlOriginal, TimeGenerated, HttpUserAgentOriginal\n| extend IPCustomEntity = SrcIpAddr, UrlCustomEntity = UrlOriginal\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P14D",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0,
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "CommandAndControl"
        ],
        "alertRuleTemplateName": "8c8de3fa-6425-4623-9cd9-45de1dd0569a",
        "customDetails": null,
        "entityMappings": [
          {
            "fieldMappings": [
              {
                "identifier": "Url",
                "columnName": "UrlCustomEntity"
              }
            ],
            "entityType": "URL"
          },
          {
            "fieldMappings": [
              {
                "identifier": "Address",
                "columnName": "IPCustomEntity"
              }
            ],
            "entityType": "IP"
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Detections/CiscoUmbrella/CiscoUmbrellaRareUserAgentDetected.yaml",
        "templateVersion": "1.1.1"
      }
    }
  ]
}