GreyNoise TI Map IP Entity to DnsEvents

let dt_lookBack = 1h; // Look back 1 hour for DNS events
let ioc_lookBack = 14d; // Look back 14 days for threat intelligence indicators
// Fetch threat intelligence indicators related to IP addresses
let IP_Indicators = ThreatIntelligenceIndicator
  | where TimeGenerated >= ago(ioc_lookBack)
  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
  | where Active == true and ExpirationDateTime > now()
  | where SourceSystem == 'GreyNoise'
  | where isnotempty(NetworkIP) or isnotempty(EmailSourceIpAddress) or isnotempty(NetworkDestinationIP) or isnotempty(NetworkSourceIP)
  | extend TI_ipEntity = iff(isnotempty(NetworkIP), NetworkIP, NetworkDestinationIP)
  | extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(NetworkSourceIP), NetworkSourceIP, TI_ipEntity)
  | extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(EmailSourceIpAddress), EmailSourceIpAddress, TI_ipEntity)
  | where ipv4_is_private(TI_ipEntity) == false and  TI_ipEntity !startswith "fe80" and TI_ipEntity !startswith "::" and TI_ipEntity !startswith "127.";
// Perform a join between IP indicators and DNS events
IP_Indicators
  // Use innerunique to keep performance fast and result set low, as we only need one match to indicate potential malicious activity that needs investigation
  | join kind=innerunique (
      DnsEvents
      | where TimeGenerated >= ago(dt_lookBack)
      | where SubType =~ "LookupQuery" and isnotempty(IPAddresses)
      | mv-expand SingleIP = split(IPAddresses, ", ") to typeof(string)
      | extend DNS_TimeGenerated = TimeGenerated
  )
  on $left.TI_ipEntity == $right.SingleIP
  // Filter out DNS events that occurred after the expiration of the corresponding indicator
  | where DNS_TimeGenerated < ExpirationDateTime
  // Group the results by IndicatorId and SingleIP, and keep the DNS event with the latest timestamp
  | summarize DNS_TimeGenerated = arg_max(DNS_TimeGenerated, *) by IndicatorId, SingleIP
  // Select the desired output fields
  | project DNS_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, DomainName, ExpirationDateTime, ConfidenceScore,
    TI_ipEntity, Computer, EventId, SubType, ClientIP, Name, IPAddresses, NetworkIP, NetworkDestinationIP, NetworkSourceIP, EmailSourceIpAddress, Type
  | extend timestamp = DNS_TimeGenerated, HostName = tostring(split(Computer, '.', 0)[0]), DnsDomain = tostring(strcat_array(array_slice(split(Computer, '.'), 1, -1), '.'))

relevantTechniques:
- T1071
name: GreyNoise TI Map IP Entity to DnsEvents
requiredDataConnectors:
- dataTypes:
  - ThreatIntelligenceIndicator
  connectorId: ThreatIntelligence
- dataTypes:
  - ThreatIntelligenceIndicator
  connectorId: ThreatIntelligenceTaxii
- dataTypes:
  - DnsEvents
  connectorId: DNS
- dataTypes:
  - DnsEvents
  connectorId: ASimDnsActivityLogs
- dataTypes:
  - ThreatIntelligenceIndicator
  connectorId: GreyNoise2SentinelAPI
entityMappings:
- fieldMappings:
  - identifier: HostName
    columnName: HostName
  - identifier: DnsDomain
    columnName: DnsDomain
  entityType: Host
- fieldMappings:
  - identifier: Address
    columnName: ClientIP
  entityType: IP
- fieldMappings:
  - identifier: Url
    columnName: Url
  entityType: URL
triggerThreshold: 0
id: ddf47b6f-870c-5712-a296-1383acb13c82
tactics:
- CommandAndControl
version: 1.0.2
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/GreyNoiseThreatIntelligence/Analytic Rules/GreyNoise_IPEntity_DnsEvents.yaml
queryPeriod: 14d
kind: Scheduled
queryFrequency: 1h
severity: Medium
description: |
    This query maps any IP indicators of compromise (IOCs) from GreyNoise Threat Intelligence (TI), by searching for matches in DnsEvents.
query: |
  let dt_lookBack = 1h; // Look back 1 hour for DNS events
  let ioc_lookBack = 14d; // Look back 14 days for threat intelligence indicators
  // Fetch threat intelligence indicators related to IP addresses
  let IP_Indicators = ThreatIntelligenceIndicator
    | where TimeGenerated >= ago(ioc_lookBack)
    | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
    | where Active == true and ExpirationDateTime > now()
    | where SourceSystem == 'GreyNoise'
    | where isnotempty(NetworkIP) or isnotempty(EmailSourceIpAddress) or isnotempty(NetworkDestinationIP) or isnotempty(NetworkSourceIP)
    | extend TI_ipEntity = iff(isnotempty(NetworkIP), NetworkIP, NetworkDestinationIP)
    | extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(NetworkSourceIP), NetworkSourceIP, TI_ipEntity)
    | extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(EmailSourceIpAddress), EmailSourceIpAddress, TI_ipEntity)
    | where ipv4_is_private(TI_ipEntity) == false and  TI_ipEntity !startswith "fe80" and TI_ipEntity !startswith "::" and TI_ipEntity !startswith "127.";
  // Perform a join between IP indicators and DNS events
  IP_Indicators
    // Use innerunique to keep performance fast and result set low, as we only need one match to indicate potential malicious activity that needs investigation
    | join kind=innerunique (
        DnsEvents
        | where TimeGenerated >= ago(dt_lookBack)
        | where SubType =~ "LookupQuery" and isnotempty(IPAddresses)
        | mv-expand SingleIP = split(IPAddresses, ", ") to typeof(string)
        | extend DNS_TimeGenerated = TimeGenerated
    )
    on $left.TI_ipEntity == $right.SingleIP
    // Filter out DNS events that occurred after the expiration of the corresponding indicator
    | where DNS_TimeGenerated < ExpirationDateTime
    // Group the results by IndicatorId and SingleIP, and keep the DNS event with the latest timestamp
    | summarize DNS_TimeGenerated = arg_max(DNS_TimeGenerated, *) by IndicatorId, SingleIP
    // Select the desired output fields
    | project DNS_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, DomainName, ExpirationDateTime, ConfidenceScore,
      TI_ipEntity, Computer, EventId, SubType, ClientIP, Name, IPAddresses, NetworkIP, NetworkDestinationIP, NetworkSourceIP, EmailSourceIpAddress, Type
    | extend timestamp = DNS_TimeGenerated, HostName = tostring(split(Computer, '.', 0)[0]), DnsDomain = tostring(strcat_array(array_slice(split(Computer, '.'), 1, -1), '.'))  
triggerOperator: gt

{
  "$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/ddf47b6f-870c-5712-a296-1383acb13c82')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/ddf47b6f-870c-5712-a296-1383acb13c82')]",
      "properties": {
        "alertRuleTemplateName": "ddf47b6f-870c-5712-a296-1383acb13c82",
        "customDetails": null,
        "description": "This query maps any IP indicators of compromise (IOCs) from GreyNoise Threat Intelligence (TI), by searching for matches in DnsEvents.\n",
        "displayName": "GreyNoise TI Map IP Entity to DnsEvents",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "columnName": "HostName",
                "identifier": "HostName"
              },
              {
                "columnName": "DnsDomain",
                "identifier": "DnsDomain"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "ClientIP",
                "identifier": "Address"
              }
            ]
          },
          {
            "entityType": "URL",
            "fieldMappings": [
              {
                "columnName": "Url",
                "identifier": "Url"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/GreyNoiseThreatIntelligence/Analytic Rules/GreyNoise_IPEntity_DnsEvents.yaml",
        "query": "let dt_lookBack = 1h; // Look back 1 hour for DNS events\nlet ioc_lookBack = 14d; // Look back 14 days for threat intelligence indicators\n// Fetch threat intelligence indicators related to IP addresses\nlet IP_Indicators = ThreatIntelligenceIndicator\n  | where TimeGenerated >= ago(ioc_lookBack)\n  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId\n  | where Active == true and ExpirationDateTime > now()\n  | where SourceSystem == 'GreyNoise'\n  | where isnotempty(NetworkIP) or isnotempty(EmailSourceIpAddress) or isnotempty(NetworkDestinationIP) or isnotempty(NetworkSourceIP)\n  | extend TI_ipEntity = iff(isnotempty(NetworkIP), NetworkIP, NetworkDestinationIP)\n  | extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(NetworkSourceIP), NetworkSourceIP, TI_ipEntity)\n  | extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(EmailSourceIpAddress), EmailSourceIpAddress, TI_ipEntity)\n  | where ipv4_is_private(TI_ipEntity) == false and  TI_ipEntity !startswith \"fe80\" and TI_ipEntity !startswith \"::\" and TI_ipEntity !startswith \"127.\";\n// Perform a join between IP indicators and DNS events\nIP_Indicators\n  // Use innerunique to keep performance fast and result set low, as we only need one match to indicate potential malicious activity that needs investigation\n  | join kind=innerunique (\n      DnsEvents\n      | where TimeGenerated >= ago(dt_lookBack)\n      | where SubType =~ \"LookupQuery\" and isnotempty(IPAddresses)\n      | mv-expand SingleIP = split(IPAddresses, \", \") to typeof(string)\n      | extend DNS_TimeGenerated = TimeGenerated\n  )\n  on $left.TI_ipEntity == $right.SingleIP\n  // Filter out DNS events that occurred after the expiration of the corresponding indicator\n  | where DNS_TimeGenerated < ExpirationDateTime\n  // Group the results by IndicatorId and SingleIP, and keep the DNS event with the latest timestamp\n  | summarize DNS_TimeGenerated = arg_max(DNS_TimeGenerated, *) by IndicatorId, SingleIP\n  // Select the desired output fields\n  | project DNS_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, DomainName, ExpirationDateTime, ConfidenceScore,\n    TI_ipEntity, Computer, EventId, SubType, ClientIP, Name, IPAddresses, NetworkIP, NetworkDestinationIP, NetworkSourceIP, EmailSourceIpAddress, Type\n  | extend timestamp = DNS_TimeGenerated, HostName = tostring(split(Computer, '.', 0)[0]), DnsDomain = tostring(strcat_array(array_slice(split(Computer, '.'), 1, -1), '.'))\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "P14D",
        "severity": "Medium",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "CommandAndControl"
        ],
        "techniques": [
          "T1071"
        ],
        "templateVersion": "1.0.2",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}