TI map IP entity to OfficeActivity

Original query, unchanged.

let dt_lookBack = 1h; // Look back 1 hour for OfficeActivity events
let ioc_lookBack = 14d; // Look back 14 days for threat intelligence indicators
let OfficeActivity_ = materialize(OfficeActivity
  | where isnotempty(ClientIP)
  | where TimeGenerated >= ago(dt_lookBack)
  | extend ClientIPValues = extract_all(@'\[?(::ffff:)?(?P<IPAddress>(\d+\.\d+\.\d+\.\d+)|[^\]%]+)(%\d+)?\]?([-:](?P<Port>\d+))?', dynamic(["IPAddress", "Port"]), ClientIP)[0]
  | extend IPAddress = iff(array_length(ClientIPValues) > 0, tostring(ClientIPValues[0]), '')
  | project-rename OfficeActivity_TimeGenerated = TimeGenerated);
let ActivityIPs = OfficeActivity_ | summarize IPs = make_list(IPAddress);
// Fetch threat intelligence indicators related to IP addresses
let IP_Indicators = materialize(ThreatIntelligenceIndicator
  | where isnotempty(NetworkIP) or isnotempty(EmailSourceIpAddress) or isnotempty(NetworkDestinationIP) or isnotempty(NetworkSourceIP)
  | where TimeGenerated >= ago(ioc_lookBack)
  | extend TI_ipEntity = coalesce(NetworkDestinationIP, NetworkSourceIP, EmailSourceIpAddress)
  | where TI_ipEntity in (ActivityIPs)
  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
  | where  Active == true and ExpirationDateTime > now()
  | where Description !contains_cs "State: inactive;" and Description !contains_cs "State: falsepos;");
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 (OfficeActivity_)
  on $left.TI_ipEntity == $right.IPAddress
// Filter out OfficeActivity events that occurred after the expiration of the corresponding indicator
| where OfficeActivity_TimeGenerated < ExpirationDateTime
// Group the results by IndicatorId and keep the OfficeActivity event with the latest timestamp
| summarize OfficeActivity_TimeGenerated = arg_max(OfficeActivity_TimeGenerated, *) by IndicatorId
// Select the desired output fields
| project OfficeActivity_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, ExpirationDateTime, ConfidenceScore, TI_ipEntity, ClientIP, UserId, Operation, ResultStatus, RecordType, OfficeObjectId, NetworkIP, NetworkDestinationIP, NetworkSourceIP, EmailSourceIpAddress, Type
| extend timestamp = OfficeActivity_TimeGenerated, Name = tostring(split(UserId, '@', 0)[0]), UPNSuffix = tostring(split(UserId, '@', 1)[0])