Microsoft Sentinel medium experimental kql
TI map Domain entity to EmailUrlInfo
'Identifies a match in EmailUrlInfo table from any Domain IOC from TI.'
Detection Logic
let dt_lookBack = 1h; // Define the lookback period for email data as 1 hour
let ioc_lookBack = 14d; // Define the lookback period for threat intelligence data as 14 days
let EmailUrlInfo_ = EmailUrlInfo
| where isnotempty(Url) or isnotempty(UrlDomain) // Filter for non-empty URLs or URL domains
| where TimeGenerated >= ago(dt_lookBack) // Filter for records within the lookback period
| extend Url = tolower(Url), UrlDomain = tolower(UrlDomain) // Convert URLs and domains to lowercase
| extend EmailUrlInfo_TimeGenerated = TimeGenerated; // Create a new column for the time generated
let EmailEvents_ = EmailEvents
| where TimeGenerated >= ago(dt_lookBack); // Filter email events within the lookback period
let TI_Urls = ThreatIntelligenceIndicator
| where TimeGenerated >= ago(ioc_lookBack) // Filter threat intelligence indicators within the lookback period
| where isnotempty(Url) // Filter for non-empty URLs
| extend Url = tolower(Url) // Convert URLs to lowercase
| join kind=innerunique (EmailUrlInfo_) on Url // Join with email URL info on URL
| where Active == true and ExpirationDateTime > now() // Filter for active indicators that haven't expired
| where EmailUrlInfo_TimeGenerated < ExpirationDateTime // Ensure email info was generated before the indicator expired
| summarize EmailUrlInfo_TimeGenerated = arg_max(EmailUrlInfo_TimeGenerated, *) by IndicatorId, Url // Get the latest email info for each indicator
| project EmailUrlInfo_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, Url, UrlLocation, NetworkMessageId; // Select relevant columns
let TI_Domains = ThreatIntelligenceIndicator
| where TimeGenerated >= ago(ioc_lookBack) // Filter threat intelligence indicators within the lookback period
| where isnotempty(DomainName) // Filter for non-empty domain names
| extend DomainName = tolower(DomainName) // Convert domain names to lowercase
| join kind=innerunique (EmailUrlInfo_) on $left.DomainName == $right.UrlDomain // Join with email URL info on domain name
| where Active == true and ExpirationDateTime > now() // Filter for active indicators that haven't expired
| where EmailUrlInfo_TimeGenerated < ExpirationDateTime // Ensure email info was generated before the indicator expired
| summarize EmailUrlInfo_TimeGenerated = arg_max(EmailUrlInfo_TimeGenerated, *) by IndicatorId, UrlDomain // Get the latest email info for each indicator
| project EmailUrlInfo_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, UrlDomain, UrlLocation, NetworkMessageId; // Select relevant columns
union TI_Urls, TI_Domains // Combine URL and domain threat intelligence data
| extend timestamp = EmailUrlInfo_TimeGenerated // Add a timestamp column
| join kind=inner (EmailEvents_) on NetworkMessageId // Join with email events on network message ID
| where DeliveryAction !has "Blocked" // Filter out blocked delivery actions
| extend Name = tostring(split(RecipientEmailAddress, '@', 0)[0]), UPNSuffix = tostring(split(RecipientEmailAddress, '@', 1)[0]); // Extract name and UPN suffix from recipient email address Field Validations
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