Microsoft Sentinel Analytic Rules
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Detect DNS queries reporting multiple errors from different clients - Static threshold based ASIM DNS Solution

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Id5b8344eb-fa28-4ac3-bcff-bc19d5d63089
RulenameDetect DNS queries reporting multiple errors from different clients - Static threshold based (ASIM DNS Solution)
DescriptionThis rule creates an alert when multiple clients report errors for the same DNS query. This helps in identifying possible similar C2 communications originating from different clients. It utilizes ASIM normalization and is applied to any source that supports the ASIM DNS schema.
SeverityMedium
TacticsCommandAndControl
TechniquesT1568
T1573
T1008
KindScheduled
Query frequency1h
Query period1h
Trigger threshold0
Trigger operatorgt
Source Urihttps://github.com/Azure/Azure-Sentinel/blob/master/Solutions/DNS Essentials/Analytic Rules/MultipleErrorsReportedForSameDNSQueryStaticThresholdBased.yaml
Version1.0.4
Arm template5b8344eb-fa28-4ac3-bcff-bc19d5d63089.json
Deploy To Azure
let lookback=1h;
let threshold = 2;
let errors = dynamic(['NXDOMAIN', 'SERVFAIL', 'REFUSED']); 
_Im_Dns(starttime=ago(lookback)) 
  | where EventResultDetails has_any (errors) 
  | summarize SrcIPs = make_set(SrcIpAddr, 100), Dvcs = make_set(Dvc, 100), ResourceIds = make_set(_ResourceId, 100) by DnsQuery, bin(TimeGenerated, 10min) 
  | where array_length(SrcIPs) >= threshold 
  | extend TotalIPs = array_length(SrcIPs),IPCountthreshold = threshold 
  | extend DomainName = strcat(split(DnsQuery, ".")[1], ".", split(DnsQuery, ".")[2])  
  | mv-expand SrcIPs  
  | extend SrcIP = tostring(SrcIPs)  
  | mv-expand Dvcs  
  | extend Dvc = tostring(Dvcs)  
  | mv-expand ResourceIds  
  | extend ResourceId = tostring(ResourceIds)  
  | extend Dvc = strcat(split(Dvc, ".")[0])
  | summarize Start=min(TimeGenerated), End=max(TimeGenerated) by SrcIP, Dvc, ResourceId, DnsQuery, DomainName, SrcIPs = tostring(SrcIPs), IPCountthreshold = threshold, TotalIPs
  | extend HostName = tostring(split(Dvc, ".")[0]), DomainIndex = toint(indexof(Dvc, '.'))
  | extend HostNameDomain = iff(DomainIndex != -1, substring(Dvc, DomainIndex + 1), Dvc)
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/DNS Essentials/Analytic Rules/MultipleErrorsReportedForSameDNSQueryStaticThresholdBased.yaml
query: |
  let lookback=1h;
  let threshold = 2;
  let errors = dynamic(['NXDOMAIN', 'SERVFAIL', 'REFUSED']); 
  _Im_Dns(starttime=ago(lookback)) 
    | where EventResultDetails has_any (errors) 
    | summarize SrcIPs = make_set(SrcIpAddr, 100), Dvcs = make_set(Dvc, 100), ResourceIds = make_set(_ResourceId, 100) by DnsQuery, bin(TimeGenerated, 10min) 
    | where array_length(SrcIPs) >= threshold 
    | extend TotalIPs = array_length(SrcIPs),IPCountthreshold = threshold 
    | extend DomainName = strcat(split(DnsQuery, ".")[1], ".", split(DnsQuery, ".")[2])  
    | mv-expand SrcIPs  
    | extend SrcIP = tostring(SrcIPs)  
    | mv-expand Dvcs  
    | extend Dvc = tostring(Dvcs)  
    | mv-expand ResourceIds  
    | extend ResourceId = tostring(ResourceIds)  
    | extend Dvc = strcat(split(Dvc, ".")[0])
    | summarize Start=min(TimeGenerated), End=max(TimeGenerated) by SrcIP, Dvc, ResourceId, DnsQuery, DomainName, SrcIPs = tostring(SrcIPs), IPCountthreshold = threshold, TotalIPs
    | extend HostName = tostring(split(Dvc, ".")[0]), DomainIndex = toint(indexof(Dvc, '.'))
    | extend HostNameDomain = iff(DomainIndex != -1, substring(Dvc, DomainIndex + 1), Dvc)  
description: |
    'This rule creates an alert when multiple clients report errors for the same DNS query. This helps in identifying possible similar C2 communications originating from different clients. It utilizes [ASIM](https://aka.ms/AboutASIM) normalization and is applied to any source that supports the ASIM DNS schema.'
severity: Medium
requiredDataConnectors: []
eventGroupingSettings:
  aggregationKind: SingleAlert
tags:
- Schema: ASimDns
  SchemaVersion: 0.1.6
triggerThreshold: 0
version: 1.0.4
customDetails:
  TotalIPs: TotalIPs
  IPCountthreshold: IPCountthreshold
  SrcIPs: SrcIPs
entityMappings:
- entityType: DNS
  fieldMappings:
  - columnName: DnsQuery
    identifier: DomainName
- entityType: IP
  fieldMappings:
  - columnName: SrcIP
    identifier: Address
- entityType: AzureResource
  fieldMappings:
  - columnName: ResourceId
    identifier: ResourceId
- entityType: Url
  fieldMappings:
  - columnName: DnsQuery
    identifier: Url
- entityType: Host
  fieldMappings:
  - columnName: HostName
    identifier: HostName
  - columnName: HostNameDomain
    identifier: NTDomain
tactics:
- CommandAndControl
alertDetailsOverride:
  alertDescriptionFormat: |-
    Multiple errors were detected on different clients for the same DNS query. These unsuccessful responses can be an indication of C2 communication. 

    Threshold for total clients reporting errors: '{{IPCountthreshold}}'

    Current count of clients reporting errors for this DNS query: '{{TotalIPs}}'

    Clients requesting this DNSQuery include:

    '{{SrcIPs}}'    
  alertDisplayNameFormat: "[Static threshold] Multiple errors for the same DNS query has been detected - '{{DnsQuery}}'"
relevantTechniques:
- T1568
- T1573
- T1008
triggerOperator: gt
name: Detect DNS queries reporting multiple errors from different clients - Static threshold based (ASIM DNS Solution)
id: 5b8344eb-fa28-4ac3-bcff-bc19d5d63089
status: Available
kind: Scheduled
queryFrequency: 1h
queryPeriod: 1h
{
  "$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/5b8344eb-fa28-4ac3-bcff-bc19d5d63089')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/5b8344eb-fa28-4ac3-bcff-bc19d5d63089')]",
      "properties": {
        "alertDetailsOverride": {
          "alertDescriptionFormat": "Multiple errors were detected on different clients for the same DNS query. These unsuccessful responses can be an indication of C2 communication. \n\nThreshold for total clients reporting errors: '{{IPCountthreshold}}'\n\nCurrent count of clients reporting errors for this DNS query: '{{TotalIPs}}'\n\nClients requesting this DNSQuery include:\n\n'{{SrcIPs}}'",
          "alertDisplayNameFormat": "[Static threshold] Multiple errors for the same DNS query has been detected - '{{DnsQuery}}'"
        },
        "alertRuleTemplateName": "5b8344eb-fa28-4ac3-bcff-bc19d5d63089",
        "customDetails": {
          "IPCountthreshold": "IPCountthreshold",
          "SrcIPs": "SrcIPs",
          "TotalIPs": "TotalIPs"
        },
        "description": "'This rule creates an alert when multiple clients report errors for the same DNS query. This helps in identifying possible similar C2 communications originating from different clients. It utilizes [ASIM](https://aka.ms/AboutASIM) normalization and is applied to any source that supports the ASIM DNS schema.'\n",
        "displayName": "Detect DNS queries reporting multiple errors from different clients - Static threshold based (ASIM DNS Solution)",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "DNS",
            "fieldMappings": [
              {
                "columnName": "DnsQuery",
                "identifier": "DomainName"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "SrcIP",
                "identifier": "Address"
              }
            ]
          },
          {
            "entityType": "AzureResource",
            "fieldMappings": [
              {
                "columnName": "ResourceId",
                "identifier": "ResourceId"
              }
            ]
          },
          {
            "entityType": "Url",
            "fieldMappings": [
              {
                "columnName": "DnsQuery",
                "identifier": "Url"
              }
            ]
          },
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "columnName": "HostName",
                "identifier": "HostName"
              },
              {
                "columnName": "HostNameDomain",
                "identifier": "NTDomain"
              }
            ]
          }
        ],
        "eventGroupingSettings": {
          "aggregationKind": "SingleAlert"
        },
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/DNS Essentials/Analytic Rules/MultipleErrorsReportedForSameDNSQueryStaticThresholdBased.yaml",
        "query": "let lookback=1h;\nlet threshold = 2;\nlet errors = dynamic(['NXDOMAIN', 'SERVFAIL', 'REFUSED']); \n_Im_Dns(starttime=ago(lookback)) \n  | where EventResultDetails has_any (errors) \n  | summarize SrcIPs = make_set(SrcIpAddr, 100), Dvcs = make_set(Dvc, 100), ResourceIds = make_set(_ResourceId, 100) by DnsQuery, bin(TimeGenerated, 10min) \n  | where array_length(SrcIPs) >= threshold \n  | extend TotalIPs = array_length(SrcIPs),IPCountthreshold = threshold \n  | extend DomainName = strcat(split(DnsQuery, \".\")[1], \".\", split(DnsQuery, \".\")[2])  \n  | mv-expand SrcIPs  \n  | extend SrcIP = tostring(SrcIPs)  \n  | mv-expand Dvcs  \n  | extend Dvc = tostring(Dvcs)  \n  | mv-expand ResourceIds  \n  | extend ResourceId = tostring(ResourceIds)  \n  | extend Dvc = strcat(split(Dvc, \".\")[0])\n  | summarize Start=min(TimeGenerated), End=max(TimeGenerated) by SrcIP, Dvc, ResourceId, DnsQuery, DomainName, SrcIPs = tostring(SrcIPs), IPCountthreshold = threshold, TotalIPs\n  | extend HostName = tostring(split(Dvc, \".\")[0]), DomainIndex = toint(indexof(Dvc, '.'))\n  | extend HostNameDomain = iff(DomainIndex != -1, substring(Dvc, DomainIndex + 1), Dvc)\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",
          "T1573"
        ],
        "templateVersion": "1.0.4",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}