{
  "$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/4ab8b09e-3c23-4974-afbe-7e653779eb2b')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/4ab8b09e-3c23-4974-afbe-7e653779eb2b')]",
      "properties": {
        "alertDetailsOverride": {
          "alertDescriptionFormat": "Client is generating excessive amount of DNS queries for non-existent domains. This can be an indication of possible C2 communications. \n\n'NXDOMAIN' error count threshold: '{{NXDOMAINthreshold}}'\n\nCurrent 'NXDOMAIN' error count from this client: '{{NXDOMAINCount}}'\n\nDNS queries requested by the client include:\n\n'{{DNSQueries}}'",
          "alertDisplayNameFormat": "[Static threshold] Excessive NXDOMAIN DNS Queries has been detected from client IP: '{{SrcIpAddr}}'"
        },
        "alertRuleTemplateName": "4ab8b09e-3c23-4974-afbe-7e653779eb2b",
        "customDetails": {
          "DNSQueries": "DNSQueries",
          "NXDOMAINCount": "NXDOMAINCount",
          "NXDOMAINthreshold": "NXDOMAINthreshold"
        },
        "description": "'This rule generates an alert when the configured threshold for DNS queries to non-existent domains is breached. This helps in identifying possible C2 communications. It utilizes [ASIM](https://aka.ms/AboutASIM) normalization and is applied to any source that supports the ASIM DNS schema.'\n",
        "displayName": "Detect excessive NXDOMAIN DNS queries - Static threshold based (ASIM DNS Solution)",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "SrcIpAddr",
                "identifier": "Address"
              }
            ]
          }
        ],
        "eventGroupingSettings": {
          "aggregationKind": "AlertPerResult"
        },
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/DNS%20Essentials/Analytic%20Rules/ExcessiveNXDOMAINDNSQueriesStaticThresholdBased.yaml",
        "query": "let lookback = 1h;\nlet threshold = 200;\n_Im_Dns(starttime=ago(lookback), responsecodename='NXDOMAIN')\n| summarize NXDOMAINCount=count() by SrcIpAddr, bin(TimeGenerated, 15m)\n| where NXDOMAINCount > threshold\n| join kind=inner (_Im_Dns(starttime=ago(lookback), responsecodename='NXDOMAIN')\n  | summarize DNSQueries = makeset(DnsQuery) by SrcIpAddr)\n  on SrcIpAddr\n| extend NXDOMAINthreshold=threshold\n| project-away SrcIpAddr1\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "PT1H",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "CommandAndControl"
        ],
        "tags": [
          {
            "Schema": "ASimDns",
            "SchemaVersion": "0.1.6"
          }
        ],
        "techniques": [
          "T1008",
          "T1568"
        ],
        "templateVersion": "1.0.2",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}