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 = 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 = ObservableValue
  | extend TrafficLightProtocolLevel = tostring(parse_json(AdditionalFields).TLPLevel)
  // Filter out indicators without relevant IP address fields
  | 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 Confidence > 50
  // Select the IP entity based on availability of different IP fields
  | 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, "")
  // Determine Severity based on ConfidenceScore
  | extend Severity = case(Confidence > 82, "High",
                                Confidence > 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 Id, ObservableValue
  | where IsActive and (ValidUntil > now() or isempty(ValidUntil));
  // Perform a join between IP indicators and AppServiceHTTPLogs to identify potential malicious activity
IP_Indicators
| project-reorder *, IsActive, Tags, TrafficLightProtocolLevel, NetworkSourceIP, Type, TI_ipEntity, Severity
  // 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 < ValidUntil
  // Group the results by IndicatorId and CIp, and keep the log entry with the latest timestamp
  | summarize AppService_TimeGenerated = arg_max(AppService_TimeGenerated, *) by Id, CIp
  // Select the desired output fields
  | extend Description = tostring(parse_json(Data).description)
  | extend ActivityGroupNames = extract(@"ActivityGroup:(\S+)", 1, tostring(parse_json(Data).labels))
  | project AppService_TimeGenerated, Description, ActivityGroupNames, Id, ValidUntil, Confidence, TI_ipEntity, CsUsername, WebApp = split(_ResourceId, '/')[8], CIp, CsHost, NetworkSourceIP, _ResourceId, Type, Url, Severity
  // 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