TI Map File Hash to DeviceFileEvents Event

Original query, unchanged.

let dt_lookBack = 1h;
let ioc_lookBack = 14d;
let DeviceFileEvents_ = (union
(DeviceFileEvents | where TimeGenerated > ago(dt_lookBack) | where isnotempty(SHA1) | extend FileHashValue = SHA1),
(DeviceFileEvents | where TimeGenerated > ago(dt_lookBack) | where isnotempty(SHA256) | extend FileHashValue = SHA256));
let Hashes = DeviceFileEvents_ | distinct FileHashValue;
ThreatIntelIndicators
//extract key part of kv pair
      | extend IndicatorType = replace(@"\[|\]|\""", "", tostring(split(ObservableKey, ":", 0)))
      | where IndicatorType == "file"
      | extend FileHashType = replace("'", "", substring(ObservableKey, indexof(ObservableKey, "hashes.") + 7, strlen(ObservableKey) - indexof(ObservableKey, "hashes.") - 7))
      | extend FileHashValue = ObservableValue
      | extend IndicatorId = tostring(split(Id, "--")[2])
| where isnotempty(FileHashValue)
| where TimeGenerated > ago(ioc_lookBack)
//  | where FileHashValue in (Hashes)
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id, ObservableValue
| where IsActive and (ValidUntil > now() or isempty(ValidUntil))
| extend Description = tostring(parse_json(Data).description)
| where Description !contains_cs "State: inactive;" and Description !contains_cs "State: falsepos;"
  | project-reorder *, FileHashType, FileHashValue, Type
| join kind=innerunique (DeviceFileEvents_) on $left.FileHashValue == $right.FileHashValue
| where TimeGenerated < ValidUntil
| summarize TimeGenerated = arg_max(TimeGenerated, *) by  IndicatorId, DeviceId
| extend TrafficLightProtocolLevel = tostring(parse_json(AdditionalFields).TLPLevel)
| extend Description = tostring(parse_json(Data).description)
| extend ActivityGroupNames = extract(@"ActivityGroup:(\S+)", 1, tostring(parse_json(Data).labels))
| project TimeGenerated, TrafficLightProtocolLevel, Description, ActivityGroupNames, IndicatorId, FileHashValue, FileHashType, ValidUntil, Confidence, ActionType, DeviceId, DeviceName, FolderPath, RequestAccountDomain, RequestAccountName, RequestAccountSid, MachineGroup
| extend timestamp = TimeGenerated