TI map IP entity to AppServiceHTTPLogs

Original query, unchanged.

let dt_lookBack = 1h; // Look back 1 hour for AppServiceHTTPLogs
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)
  // Filtering out rows where the Confidence Score is less than 50 as they would not have an Alert Priority label. 
  | where ConfidenceScore > 50
  // 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)
  // Determine AlertPriority based on ConfidenceScore
  | extend AlertPriority = case(ConfidenceScore > 82, "High",
                                ConfidenceScore > 74, "Medium",
                                "Low")
  // 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 AppServiceHTTPLogs 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 (
    AppServiceHTTPLogs | where TimeGenerated >= ago(dt_lookBack)
    | where isnotempty(CIp)
    | extend WebApp = split(_ResourceId, '/')[8]
    | extend AppService_TimeGenerated = TimeGenerated // Rename time column for clarity
  )
  on $left.TI_ipEntity == $right.CIp
  // Filter out logs that occurred after the expiration of the corresponding indicator
  | where AppService_TimeGenerated < ExpirationDateTime
  // Group the results by IndicatorId and CIp, and keep the log entry with the latest timestamp
  | summarize AppService_TimeGenerated = arg_max(AppService_TimeGenerated, *) by IndicatorId, CIp
  // Select the desired output fields
  | project AppService_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, ExpirationDateTime, ConfidenceScore, TI_ipEntity, CsUsername, WebApp = split(_ResourceId, '/')[8], CIp, CsHost, NetworkIP, NetworkDestinationIP, NetworkSourceIP, EmailSourceIpAddress, _ResourceId, Type, AlertPriority
  // Extract hostname and DNS domain from the CsHost field
  | extend HostName = tostring(split(CsHost, '.', 0)[0]), DnsDomain = tostring(strcat_array(array_slice(split(CsHost, '.'), 1, -1), '.'))
  // Rename the timestamp field
  | extend timestamp = AppService_TimeGenerated