API - Kiterunner detection

let discoveryRecords = apifirewall_log_1_CL
| where TimeGenerated >= ago(5m) 
| project-away Non_blocking_mode_b, Source_Port_d, Destination_Port_d, Query_s, API_ID_g, Request_Header_s, Response_Header_s, Errors_s, Type, UUID_g 
| where Status_d == 404 and Error_Message_s startswith "path not defined in OAS";
let discoveryCnt = (toscalar(discoveryRecords | count));
let recCount = iff((discoveryCnt > 500), 1, 0);
discoveryRecords | top recCount by Timestamp_t desc

query: |
  let discoveryRecords = apifirewall_log_1_CL
  | where TimeGenerated >= ago(5m) 
  | project-away Non_blocking_mode_b, Source_Port_d, Destination_Port_d, Query_s, API_ID_g, Request_Header_s, Response_Header_s, Errors_s, Type, UUID_g 
  | where Status_d == 404 and Error_Message_s startswith "path not defined in OAS";
  let discoveryCnt = (toscalar(discoveryRecords | count));
  let recCount = iff((discoveryCnt > 500), 1, 0);
  discoveryRecords | top recCount by Timestamp_t desc  
eventGroupingSettings:
  aggregationKind: SingleAlert
triggerThreshold: 0
customDetails: 
queryFrequency: 5m
requiredDataConnectors:
- connectorId: 42CrunchAPIProtection
  dataTypes:
  - apifirewall_log_1_CL
id: 421b38ec-4295-4aed-8299-c92e268ad663
version: 1.0.0
name: API - Kiterunner detection
kind: Scheduled
status: Available
relevantTechniques: 
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/42Crunch API Protection/Analytic Rules/APIKiterunnerDetection.yaml
queryPeriod: 5m
severity: Medium
triggerOperator: gt
tactics:
- Reconnaissance
- Discovery
description: |
    '42Crunch API protection against Kiterunner enumeration'
entityMappings:
- entityType: IP
  fieldMappings:
  - identifier: Address
    columnName: Source_IP_s
- entityType: Host
  fieldMappings:
  - identifier: HostName
    columnName: Hostname_s
- entityType: Account
  fieldMappings:
  - identifier: FullName
    columnName: Instance_Name_s

{
  "$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/421b38ec-4295-4aed-8299-c92e268ad663')]",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/421b38ec-4295-4aed-8299-c92e268ad663')]",
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules",
      "kind": "Scheduled",
      "apiVersion": "2022-11-01",
      "properties": {
        "displayName": "API - Kiterunner detection",
        "description": "'42Crunch API protection against Kiterunner enumeration'\n",
        "severity": "Medium",
        "enabled": true,
        "query": "let discoveryRecords = apifirewall_log_1_CL\n| where TimeGenerated >= ago(5m) \n| project-away Non_blocking_mode_b, Source_Port_d, Destination_Port_d, Query_s, API_ID_g, Request_Header_s, Response_Header_s, Errors_s, Type, UUID_g \n| where Status_d == 404 and Error_Message_s startswith \"path not defined in OAS\";\nlet discoveryCnt = (toscalar(discoveryRecords | count));\nlet recCount = iff((discoveryCnt > 500), 1, 0);\ndiscoveryRecords | top recCount by Timestamp_t desc\n",
        "queryFrequency": "PT5M",
        "queryPeriod": "PT5M",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0,
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Reconnaissance",
          "Discovery"
        ],
        "techniques": null,
        "alertRuleTemplateName": "421b38ec-4295-4aed-8299-c92e268ad663",
        "eventGroupingSettings": {
          "aggregationKind": "SingleAlert"
        },
        "customDetails": null,
        "entityMappings": [
          {
            "fieldMappings": [
              {
                "columnName": "Source_IP_s",
                "identifier": "Address"
              }
            ],
            "entityType": "IP"
          },
          {
            "fieldMappings": [
              {
                "columnName": "Hostname_s",
                "identifier": "HostName"
              }
            ],
            "entityType": "Host"
          },
          {
            "fieldMappings": [
              {
                "columnName": "Instance_Name_s",
                "identifier": "FullName"
              }
            ],
            "entityType": "Account"
          }
        ],
        "templateVersion": "1.0.0",
        "status": "Available",
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/42Crunch API Protection/Analytic Rules/APIKiterunnerDetection.yaml"
      }
    }
  ]
}