Detect excessive NXDOMAIN DNS queries - Static threshold based (ASIM DNS Solution)

let lookback = 1h;
let threshold = materialize (_GetWatchlist('DNS_Solution_Monitoring_Configuration')
  | where wl_RuleName == 'Excessive NXDOMAIN DNS Queries'
      and wl_Type == 'Detection'
  | project threshold=toint(wl_Threshold));
_Im_Dns(starttime=ago(lookback), responsecodename='NXDOMAIN')
| summarize NXDOMAINCount=count() by SrcIpAddr, bin(TimeGenerated, 15m)
| where NXDOMAINCount > toscalar(threshold)
| join kind=inner (_Im_Dns(starttime=ago(lookback), responsecodename='NXDOMAIN')
  | summarize DNSQueries = makeset(DnsQuery) by SrcIpAddr)
  on SrcIpAddr
| extend NXDOMAINthreshold=toint(toscalar(threshold))
| project-away SrcIpAddr1

tactics:
- CommandAndControl
severity: Medium
requiredDataConnectors:
- connectorId: ASimDnsActivityLogs
  dataTypes:
  - ASimDnsActivityLogs
- connectorId: GCPDNSDataConnector
  dataTypes:
  - GCP_DNS_CL
- connectorId: AzureFirewall
  dataTypes:
  - AzureDiagnostics
- connectorId: CiscoUmbrellaDataConnector
  dataTypes:
  - Cisco_Umbrella_proxy_CL
- connectorId: Corelight
  dataTypes:
  - Corelight_CL
- connectorId: InfobloxNIOS
  dataTypes:
  - Syslog
- connectorId: NXLogDnsLogs
  dataTypes:
  - NXLog_DNS_Server_CL
- connectorId: DNS
  dataTypes:
  - DnsEvents
- connectorId: AIVectraStream
  dataTypes:
  - VectraStream_CL
- connectorId: WindowsForwardedEvents
  dataTypes:
  - WindowsEvents
- connectorId: Zscaler
  dataTypes:
  - CommonSecurityLog
- connectorId: ISCBind
  dataTypes:
  - Syslog
triggerOperator: gt
eventGroupingSettings:
  aggregationKind: AlertPerResult
alertDetailsOverride:
  alertDescriptionFormat: |-
    Client is generating excessive amount of DNS queries for non-existent domains. This can be an indication of possible C2 communications. 

    'NXDOMAIN' error count threshold: '{{NXDOMAINthreshold}}'

    Current 'NXDOMAIN' error count from this client: '{{NXDOMAINCount}}'

    DNS queries requested by the client include:

    '{{DNSQueries}}'    
  alertDisplayNameFormat: "[Static threshold] Excessive NXDOMAIN DNS Queries has been detected from client IP: '{{SrcIpAddr}}'"
query: |
  let lookback = 1h;
  let threshold = materialize (_GetWatchlist('DNS_Solution_Monitoring_Configuration')
    | where wl_RuleName == 'Excessive NXDOMAIN DNS Queries'
        and wl_Type == 'Detection'
    | project threshold=toint(wl_Threshold));
  _Im_Dns(starttime=ago(lookback), responsecodename='NXDOMAIN')
  | summarize NXDOMAINCount=count() by SrcIpAddr, bin(TimeGenerated, 15m)
  | where NXDOMAINCount > toscalar(threshold)
  | join kind=inner (_Im_Dns(starttime=ago(lookback), responsecodename='NXDOMAIN')
    | summarize DNSQueries = makeset(DnsQuery) by SrcIpAddr)
    on SrcIpAddr
  | extend NXDOMAINthreshold=toint(toscalar(threshold))
  | project-away SrcIpAddr1  
triggerThreshold: 0
name: Detect excessive NXDOMAIN DNS queries - Static threshold based (ASIM DNS Solution)
kind: Scheduled
version: 1.0.0
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. \n\nIt utilizes [ASIM](https://aka.ms/AboutASIM) normalization and is applied to any source that supports the ASIM DNS schema.'
relevantTechniques:
- T1568
- T1008
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/DNS Essentials/Analytic Rules/ExcessiveNXDOMAINDNSQueriesStaticThresholdBased.yaml
customDetails:
  NXDOMAINCount: NXDOMAINCount
  NXDOMAINthreshold: NXDOMAINthreshold
  DNSQueries: DNSQueries
tags:
- Schema: ASimDns
  SchemaVersion: 0.1.6
status: Available
queryFrequency: 1h
queryPeriod: 1h
entityMappings:
- entityType: IP
  fieldMappings:
  - identifier: Address
    columnName: SrcIpAddr
id: 4ab8b09e-3c23-4974-afbe-7e653779eb2b

{
  "$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/4ab8b09e-3c23-4974-afbe-7e653779eb2b')]",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/4ab8b09e-3c23-4974-afbe-7e653779eb2b')]",
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules",
      "kind": "Scheduled",
      "apiVersion": "2022-11-01",
      "properties": {
        "displayName": "Detect excessive NXDOMAIN DNS queries - Static threshold based (ASIM DNS Solution)",
        "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. \\n\\nIt utilizes [ASIM](https://aka.ms/AboutASIM) normalization and is applied to any source that supports the ASIM DNS schema.'\n",
        "severity": "Medium",
        "enabled": true,
        "query": "let lookback = 1h;\nlet threshold = materialize (_GetWatchlist('DNS_Solution_Monitoring_Configuration')\n  | where wl_RuleName == 'Excessive NXDOMAIN DNS Queries'\n      and wl_Type == 'Detection'\n  | project threshold=toint(wl_Threshold));\n_Im_Dns(starttime=ago(lookback), responsecodename='NXDOMAIN')\n| summarize NXDOMAINCount=count() by SrcIpAddr, bin(TimeGenerated, 15m)\n| where NXDOMAINCount > toscalar(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=toint(toscalar(threshold))\n| project-away SrcIpAddr1\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "PT1H",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0,
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "CommandAndControl"
        ],
        "techniques": [
          "T1568",
          "T1008"
        ],
        "alertRuleTemplateName": "4ab8b09e-3c23-4974-afbe-7e653779eb2b",
        "eventGroupingSettings": {
          "aggregationKind": "AlertPerResult"
        },
        "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}}'"
        },
        "customDetails": {
          "NXDOMAINCount": "NXDOMAINCount",
          "NXDOMAINthreshold": "NXDOMAINthreshold",
          "DNSQueries": "DNSQueries"
        },
        "entityMappings": [
          {
            "fieldMappings": [
              {
                "columnName": "SrcIpAddr",
                "identifier": "Address"
              }
            ],
            "entityType": "IP"
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/DNS Essentials/Analytic Rules/ExcessiveNXDOMAINDNSQueriesStaticThresholdBased.yaml",
        "templateVersion": "1.0.0",
        "status": "Available",
        "tags": [
          {
            "Schema": "ASimDns",
            "SchemaVersion": "0.1.6"
          }
        ]
      }
    }
  ]
}