TI map IP entity to AzureFirewall

Original query, unchanged.

let dt_lookBack = 1h; // Look back 1 hour for AzureDiagnostics logs
let ioc_lookBack = 14d; // Look back 14 days for threat intelligence indicators
// Fetch threat intelligence indicators related to IP addresses
let IP_Indicators = ThreatIntelligenceIndicator
  // Filter out indicators without relevant IP address fields
  | where isnotempty(NetworkIP) or isnotempty(EmailSourceIpAddress) or isnotempty(NetworkDestinationIP) or isnotempty(NetworkSourceIP)
  | where TimeGenerated >= ago(ioc_lookBack)
  // Select the IP entity based on availability of different IP fields
  | 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)
  // Exclude local addresses using the ipv4_is_private operator and filtering out specific address prefixes
  | 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 IndicatorId
  | where Active == true and ExpirationDateTime > now();
// Perform a join between IP indicators and AzureDiagnostics logs to identify potential malicious activity
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 (
      AzureDiagnostics
      | where TimeGenerated >= ago(dt_lookBack)
      | where OperationName in ("AzureFirewallApplicationRuleLog", "AzureFirewallNetworkRuleLog")
      | parse kind=regex flags=U msg_s with Protocol 'request from ' SourceHost 'to ' DestinationHost @'\.? Action: ' Firewall_Action @'\.' Rest_msg
      | extend SourceAddress = extract(@'([\.0-9]+)(:[\.0-9]+)?', 1, SourceHost)
      | extend DestinationAddress = extract(@'([\.0-9]+)(:[\.0-9]+)?', 1, DestinationHost)
      | extend RemoteIP = case(not(ipv4_is_private(DestinationAddress)), DestinationAddress, not(ipv4_is_private(SourceAddress)), SourceAddress, "")
      | where isnotempty(RemoteIP) // Filter out traffic involving public addresses only
      | project-rename AzureFirewall_TimeGenerated = TimeGenerated
  )
  on $left.TI_ipEntity == $right.RemoteIP
  // Filter out logs that occurred after the expiration of the corresponding indicator
  | where AzureFirewall_TimeGenerated < ExpirationDateTime
  // Group the results by IndicatorId and RemoteIP, and keep the log entry with the latest timestamp
  | summarize AzureFirewall_TimeGenerated = arg_max(AzureFirewall_TimeGenerated, *) by IndicatorId, RemoteIP
  // Select the desired output fields
  | project LatestIndicatorTime, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, DomainName, ExpirationDateTime, ConfidenceScore,
    AzureFirewall_TimeGenerated, TI_ipEntity, Resource, Category, msg_s, SourceAddress, DestinationAddress, Firewall_Action, Protocol,
    NetworkIP, NetworkDestinationIP, NetworkSourceIP, EmailSourceIpAddress, Type
  // Rename the timestamp field
  | extend timestamp = AzureFirewall_TimeGenerated