Microsoft Sentinel Analytic Rules
cloudbrothers.infoAzure Sentinel RepoToggle Dark/Light/Auto modeToggle Dark/Light/Auto modeToggle Dark/Light/Auto modeBack to homepage

Detect DNS queries reporting multiple errors from different clients - Static threshold based ASIM DNS Solution

Back
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
Version1.0.3
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
  | extend HostName = tostring(split(Dvc, ".")[0]), DomainIndex = toint(indexof(Dvc, '.'))
  | extend HostNameDomain = iff(DomainIndex != -1, substring(Dvc, DomainIndex + 1), Dvc)
triggerThreshold: 0
severity: Medium
id: 5b8344eb-fa28-4ac3-bcff-bc19d5d63089
alertDetailsOverride:
  alertDisplayNameFormat: "[Static threshold] Multiple errors for the same DNS query has been detected - '{{DnsQuery}}'"
  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}}'    
relevantTechniques:
- T1568
- T1573
- T1008
tags:
- SchemaVersion: 0.1.6
  Schema: ASimDns
status: Available
eventGroupingSettings:
  aggregationKind: SingleAlert
requiredDataConnectors: []
version: 1.0.3
queryFrequency: 1h
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/DNS Essentials/Analytic Rules/MultipleErrorsReportedForSameDNSQueryStaticThresholdBased.yaml
entityMappings:
- entityType: DNS
  fieldMappings:
  - identifier: DomainName
    columnName: DnsQuery
- entityType: IP
  fieldMappings:
  - identifier: Address
    columnName: SrcIP
- entityType: AzureResource
  fieldMappings:
  - identifier: ResourceId
    columnName: ResourceId
- entityType: Url
  fieldMappings:
  - identifier: Url
    columnName: DnsQuery
- entityType: Host
  fieldMappings:
  - identifier: HostName
    columnName: HostName
  - identifier: NTDomain
    columnName: HostNameDomain
tactics:
- CommandAndControl
triggerOperator: gt
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.'
name: Detect DNS queries reporting multiple errors from different clients - Static threshold based (ASIM DNS Solution)
queryPeriod: 1h
customDetails:
  TotalIPs: TotalIPs
  IPCountthreshold: IPCountthreshold
  SrcIPs: SrcIPs
kind: Scheduled
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
    | extend HostName = tostring(split(Dvc, ".")[0]), DomainIndex = toint(indexof(Dvc, '.'))
    | extend HostNameDomain = iff(DomainIndex != -1, substring(Dvc, DomainIndex + 1), Dvc)  
{
  "$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/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\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",
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "CommandAndControl"
        ],
        "tags": [
          {
            "Schema": "ASimDns",
            "SchemaVersion": "0.1.6"
          }
        ],
        "techniques": [
          "T1008",
          "T1568",
          "T1573"
        ],
        "templateVersion": "1.0.3",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}