TI map IP entity to AzureNetworkAnalytics_CL (NSG Flow Logs)

let dt_lookBack = 1h; // Look back 1 hour for AzureNetworkAnalytics_CL 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
| where isnotempty(NetworkIP) or isnotempty(EmailSourceIpAddress) or isnotempty(NetworkDestinationIP) or isnotempty(NetworkSourceIP)
| where TimeGenerated >= ago(ioc_lookBack)
| 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."
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
| where Active == true and ExpirationDateTime > now();
// Perform a join between IP indicators and AzureNetworkAnalytics_CL logs for NSG Flow information
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 (
      AzureNetworkAnalytics_CL
| where TimeGenerated >= ago(dt_lookBack)
| extend AzureNetworkAnalytics_CL_TimeGenerated = TimeGenerated
| extend PIPs = split(PublicIPs_s, '
| ', 0)
| extend PIP = tostring(PIPs[0])
  )
  on $left.TI_ipEntity == $right.PIP
  // Filter out logs that occurred after the expiration of the corresponding indicator
| where AzureNetworkAnalytics_CL_TimeGenerated < ExpirationDateTime
  // Filter out NSG Flow logs that are not allowed (FlowStatus_s == "A")
| where FlowStatus_s == "A"
  // Group the results by IndicatorId and PIP (Public IP), and keep the log entry with the latest timestamp
| summarize AzureNetworkAnalytics_CL_TimeGenerated = arg_max(AzureNetworkAnalytics_CL_TimeGenerated, *) by IndicatorId, PIP
  // Select the desired output fields
| project AzureNetworkAnalytics_CL_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, ExpirationDateTime, ConfidenceScore,
    TI_ipEntity, Computer, FlowDirection_s, FlowStatus_s, FlowType_s, SrcPublicIPs_s, DestPublicIPs_s, PublicIPs_s, L7Protocol_s, DestPort_d, NetworkIP, NetworkDestinationIP, NetworkSourceIP, EmailSourceIpAddress, Type
  // Extract hostname and DNS domain from the Computer field
| extend HostName = tostring(split(Computer, '.', 0)[0]), DnsDomain = tostring(strcat_array(array_slice(split(Computer, '.'), 1, -1), '.'))
  // Rename the timestamp field
| extend timestamp = AzureNetworkAnalytics_CL_TimeGenerated