Microsoft Sentinel Analytic Rules
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Excessive NXDOMAIN DNS Queries ASIM DNS Schema

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Idc3b11fb2-9201-4844-b7b9-6b7bf6d9b851
RulenameExcessive NXDOMAIN DNS Queries (ASIM DNS Schema)
DescriptionThis creates an incident in the event a client generates excessive amounts of DNS queries for non-existent domains.

This analytic rule uses ASIM and supports any built-in or custom source that supports the ASIM DNS schema
SeverityMedium
TacticsCommandAndControl
TechniquesT1568
T1008
Required data connectorsAzureFirewall
CiscoUmbrellaDataConnector
Corelight
DNS
GCPDNSDataConnector
InfobloxNIOS
NXLogDnsLogs
Zscaler
KindScheduled
Query frequency1h
Query period1h
Trigger threshold0
Trigger operatorgt
Source Urihttps://github.com/Azure/Azure-Sentinel/blob/master/Detections/ASimDNS/imDns_ExcessiveNXDOMAINDNSQueries.yaml
Version1.3.4
Arm templatec3b11fb2-9201-4844-b7b9-6b7bf6d9b851.json
Deploy To Azure
let threshold = 200;
_Im_Dns(responsecodename='NXDOMAIN')
| where isnotempty(DnsResponseCodeName)
//| where DnsResponseCodeName =~ "NXDOMAIN"
| summarize count() by SrcIpAddr, bin(TimeGenerated,15m)
| where count_ > threshold
| join kind=inner (_Im_Dns(responsecodename='NXDOMAIN')
    ) on SrcIpAddr
id: c3b11fb2-9201-4844-b7b9-6b7bf6d9b851
requiredDataConnectors:
- dataTypes:
  - DnsEvents
  connectorId: DNS
- dataTypes:
  - AzureDiagnostics
  connectorId: AzureFirewall
- dataTypes:
  - CommonSecurityLog
  connectorId: Zscaler
- dataTypes:
  - Syslog
  connectorId: InfobloxNIOS
- dataTypes:
  - GCP_DNS_CL
  connectorId: GCPDNSDataConnector
- dataTypes:
  - NXLog_DNS_Server_CL
  connectorId: NXLogDnsLogs
- dataTypes:
  - Cisco_Umbrella_dns_CL
  connectorId: CiscoUmbrellaDataConnector
- dataTypes:
  - Corelight_CL
  connectorId: Corelight
triggerOperator: gt
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/ASimDNS/imDns_ExcessiveNXDOMAINDNSQueries.yaml
relevantTechniques:
- T1568
- T1008
kind: Scheduled
name: Excessive NXDOMAIN DNS Queries (ASIM DNS Schema)
queryFrequency: 1h
query: |
  let threshold = 200;
  _Im_Dns(responsecodename='NXDOMAIN')
  | where isnotempty(DnsResponseCodeName)
  //| where DnsResponseCodeName =~ "NXDOMAIN"
  | summarize count() by SrcIpAddr, bin(TimeGenerated,15m)
  | where count_ > threshold
  | join kind=inner (_Im_Dns(responsecodename='NXDOMAIN')
      ) on SrcIpAddr  
severity: Medium
tags:
- version: 1.0.0
  ParentAlert: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/InfobloxNIOS/ExcessiveNXDOMAINDNSQueries.yaml
- SchemaVersion: 0.1.1
  Schema: ASIMDns
triggerThreshold: 0
tactics:
- CommandAndControl
entityMappings:
- fieldMappings:
  - columnName: SrcIpAddr
    identifier: Address
  entityType: IP
version: 1.3.4
metadata:
  categories:
    domains:
    - Security - Network
  support:
    tier: Community
  author:
    name: Yaron
  source:
    kind: Community
queryPeriod: 1h
description: |
  'This creates an incident in the event a client generates excessive amounts of DNS queries for non-existent domains. 
  This analytic rule uses [ASIM](https://aka.ms/AboutASIM) and supports any built-in or custom source that supports the ASIM DNS schema'  
{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2023-02-01-preview",
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/c3b11fb2-9201-4844-b7b9-6b7bf6d9b851')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/c3b11fb2-9201-4844-b7b9-6b7bf6d9b851')]",
      "properties": {
        "alertRuleTemplateName": "c3b11fb2-9201-4844-b7b9-6b7bf6d9b851",
        "customDetails": null,
        "description": "'This creates an incident in the event a client generates excessive amounts of DNS queries for non-existent domains. \nThis analytic rule uses [ASIM](https://aka.ms/AboutASIM) and supports any built-in or custom source that supports the ASIM DNS schema'\n",
        "displayName": "Excessive NXDOMAIN DNS Queries (ASIM DNS Schema)",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "SrcIpAddr",
                "identifier": "Address"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Detections/ASimDNS/imDns_ExcessiveNXDOMAINDNSQueries.yaml",
        "query": "let threshold = 200;\n_Im_Dns(responsecodename='NXDOMAIN')\n| where isnotempty(DnsResponseCodeName)\n//| where DnsResponseCodeName =~ \"NXDOMAIN\"\n| summarize count() by SrcIpAddr, bin(TimeGenerated,15m)\n| where count_ > threshold\n| join kind=inner (_Im_Dns(responsecodename='NXDOMAIN')\n    ) on SrcIpAddr\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "PT1H",
        "severity": "Medium",
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "CommandAndControl"
        ],
        "tags": [
          {
            "ParentAlert": "https://github.com/Azure/Azure-Sentinel/blob/master/Detections/InfobloxNIOS/ExcessiveNXDOMAINDNSQueries.yaml",
            "version": "1.0.0"
          },
          {
            "Schema": "ASIMDns",
            "SchemaVersion": "0.1.1"
          }
        ],
        "techniques": [
          "T1008",
          "T1568"
        ],
        "templateVersion": "1.3.4",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}