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 = ThreatIntelIndicators
//extract key part of kv pair
| extend IndicatorType = replace(@"\[|\]|\""", "", tostring(split(ObservableKey, ":", 0)))
     | where IndicatorType in ("ipv4-addr", "ipv6-addr", "network-traffic")
     | extend NetworkSourceIP = toupper(ObservableValue)
     | extend TrafficLightProtocolLevel = tostring(parse_json(AdditionalFields).TLPLevel)
  | where TimeGenerated >= ago(ioc_lookBack)
  | extend TI_ipEntity = iff(isnotempty(NetworkSourceIP), NetworkSourceIP, NetworkSourceIP)
  | extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(NetworkSourceIP), NetworkSourceIP, TI_ipEntity)
  | extend Url = iff(ObservableKey == "url:value", ObservableValue, "")
  | where ipv4_is_private(TI_ipEntity) == false and  TI_ipEntity !startswith "fe80" and TI_ipEntity !startswith "::" and TI_ipEntity !startswith "127."
  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id, ObservableValue
  | where IsActive and (ValidUntil > now() or isempty(ValidUntil));
// Perform a join between IP indicators and DNS events
IP_Indicators
   | project-reorder *, Tags, TrafficLightProtocolLevel, NetworkSourceIP, Type, TI_ipEntity
  // 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 < ValidUntil
  // Group the results by IndicatorId and SingleIP, and keep the DNS event with the latest timestamp
  | summarize DNS_TimeGenerated = arg_max(DNS_TimeGenerated, *) by Id, SingleIP
  // Select the desired output fields
  | extend Description = tostring(parse_json(Data).description)
  | extend ActivityGroupNames = extract(@"ActivityGroup:(\S+)", 1, tostring(parse_json(Data).labels))
  | project DNS_TimeGenerated, Description, ActivityGroupNames, Id, ValidUntil, Confidence, TI_ipEntity, Computer, EventId, SubType, ClientIP, Name, IPAddresses, NetworkSourceIP, Type, Url
  | extend timestamp = DNS_TimeGenerated, HostName = tostring(split(Computer, '.', 0)[0]), DnsDomain = tostring(strcat_array(array_slice(split(Computer, '.'), 1, -1), '.'))

queryPeriod: 14d
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 = ThreatIntelIndicators
  //extract key part of kv pair
  | extend IndicatorType = replace(@"\[|\]|\""", "", tostring(split(ObservableKey, ":", 0)))
       | where IndicatorType in ("ipv4-addr", "ipv6-addr", "network-traffic")
       | extend NetworkSourceIP = toupper(ObservableValue)
       | extend TrafficLightProtocolLevel = tostring(parse_json(AdditionalFields).TLPLevel)
    | where TimeGenerated >= ago(ioc_lookBack)
    | extend TI_ipEntity = iff(isnotempty(NetworkSourceIP), NetworkSourceIP, NetworkSourceIP)
    | extend TI_ipEntity = iff(isempty(TI_ipEntity) and isnotempty(NetworkSourceIP), NetworkSourceIP, TI_ipEntity)
    | extend Url = iff(ObservableKey == "url:value", ObservableValue, "")
    | where ipv4_is_private(TI_ipEntity) == false and  TI_ipEntity !startswith "fe80" and TI_ipEntity !startswith "::" and TI_ipEntity !startswith "127."
    | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id, ObservableValue
    | where IsActive and (ValidUntil > now() or isempty(ValidUntil));
  // Perform a join between IP indicators and DNS events
  IP_Indicators
     | project-reorder *, Tags, TrafficLightProtocolLevel, NetworkSourceIP, Type, TI_ipEntity
    // 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 < ValidUntil
    // Group the results by IndicatorId and SingleIP, and keep the DNS event with the latest timestamp
    | summarize DNS_TimeGenerated = arg_max(DNS_TimeGenerated, *) by Id, SingleIP
    // Select the desired output fields
    | extend Description = tostring(parse_json(Data).description)
    | extend ActivityGroupNames = extract(@"ActivityGroup:(\S+)", 1, tostring(parse_json(Data).labels))
    | project DNS_TimeGenerated, Description, ActivityGroupNames, Id, ValidUntil, Confidence, TI_ipEntity, Computer, EventId, SubType, ClientIP, Name, IPAddresses, NetworkSourceIP, Type, Url
    | extend timestamp = DNS_TimeGenerated, HostName = tostring(split(Computer, '.', 0)[0]), DnsDomain = tostring(strcat_array(array_slice(split(Computer, '.'), 1, -1), '.'))  
name: TI Map IP Entity to DnsEvents
entityMappings:
- fieldMappings:
  - columnName: Computer
    identifier: FullName
  - columnName: HostName
    identifier: HostName
  - columnName: DnsDomain
    identifier: DnsDomain
  entityType: Host
- fieldMappings:
  - columnName: ClientIP
    identifier: Address
  entityType: IP
- fieldMappings:
  - columnName: Url
    identifier: Url
  entityType: URL
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat Intelligence (NEW)/Analytic Rules/IPEntity_DnsEvents.yaml
requiredDataConnectors:
- connectorId: ThreatIntelligence
  dataTypes:
  - ThreatIntelIndicators
- connectorId: ThreatIntelligenceTaxii
  dataTypes:
  - ThreatIntelIndicators
- connectorId: DNS
  dataTypes:
  - DnsEvents
- connectorId: MicrosoftDefenderThreatIntelligence
  dataTypes:
  - ThreatIntelIndicators
description: |
    This query maps any IP indicators of compromise (IOCs) from threat intelligence (TI), by searching for matches in DnsEvents.
kind: Scheduled
version: 1.4.7
queryFrequency: 1h
severity: Medium
relevantTechniques:
- T1071
triggerOperator: gt
triggerThreshold: 0
tactics:
- CommandAndControl
id: 6418fd33-92f2-407b-bd61-91c0d4bbcb8a