TI Map Domain entity to DnsEvents

// Define the lookback periods for time-based filters
let dt_lookBack = 1h; // Look back 1 hour for DNS events
let ioc_lookBack = 14d; // Look back 14 days for threat intelligence indicators
// Fetch threat intelligence indicators related to domains
let Domain_Indicators = ThreatIntelIndicators
  // Filter out indicators without domain names
| extend IndicatorType = replace(@"\[
| \]
| \""", "", tostring(split(ObservableKey, ":", 0)))
| where IndicatorType == "domain-name"
| extend DomainName = tolower(ObservableValue)
| extend TrafficLightProtocolLevel = tostring(parse_json(AdditionalFields).TLPLevel)
| extend Url = iff(ObservableKey == "url:value", ObservableValue, "")
| where TimeGenerated >= ago(ioc_lookBack)
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by Id, ObservableValue
| where IsActive and (ValidUntil > now() or isempty(ValidUntil));
// Create a list of TLDs in our threat feed for later validation
let maxListSize = 100000; // Define the maximum allowed size for each list
let list_tlds = Domain_Indicators
| extend parts = split(DomainName, '.')
| extend tld = parts[(array_length(parts)-1)]
| extend IndicatorId = tostring(split(Id, "--")[2])
| summarize count() by tostring(tld)
| project tld
| summarize make_list(tld, maxListSize);
// Perform a join between domain indicators and DNS events to identify potential malicious activity
Domain_Indicators
| project-reorder *, IsActive, Tags, TrafficLightProtocolLevel, DomainName, Type
  // 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 (
    DnsEvents
| where TimeGenerated > ago(dt_lookBack)
    // Extract domain patterns from syslog message
| where isnotempty(Name)
| extend parts = split(Name, '.')
| extend tld = parts[(array_length(parts)-1)]
    // Validate parsed domain by checking if the TLD is in the list of TLDs in our threat feed
| where tld in~ (list_tlds)
| extend DNS_TimeGenerated = TimeGenerated
  ) on $left.DomainName==$right.Name
  // Filter out DNS events that occurred after the expiration of the corresponding indicator
| where DNS_TimeGenerated < ValidUntil
  // Group the results by IndicatorId and Name, and keep the DNS event with the latest timestamp
| summarize DNS_TimeGenerated = arg_max(DNS_TimeGenerated, *) by Id, Name
  // Select the desired output fields
| extend ActivityGroupNames = extract(@"ActivityGroup:(\S+)", 1, tostring(parse_json(Data).labels))
| project DNS_TimeGenerated, Description, ActivityGroupNames, Id, ValidUntil, Confidence, Url, Computer, ClientIP//, Name, QueryType, Type, DomainName
  // 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 = DNS_TimeGenerated