Solutions/Threat Intelligence (NEW)/Analytic Rules/DomainEntity_EmailUrlInfo_Updated.yaml

id: b56e2290-c65b-45a5-9636-3651e85bbe5d
name: TI map Domain entity to EmailUrlInfo
description: |
  'Identifies a match in EmailUrlInfo table from any Domain IOC from TI.'
severity: Medium
requiredDataConnectors:
  - connectorId: Office365
    dataTypes:
      - EmailUrlInfo
  - connectorId: ThreatIntelligence
    dataTypes:
      - ThreatIntelligenceIndicator
  - connectorId: ThreatIntelligenceTaxii
    dataTypes:
      - ThreatIntelligenceIndicator
  - connectorId: MicrosoftDefenderThreatIntelligence
    dataTypes:
      - ThreatIntelligenceIndicator
queryFrequency: 1h
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - InitialAccess
relevantTechniques:
  - T1566
query: |
    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 = ThreatIntelIndicators
    | where TimeGenerated >= ago(ioc_lookBack) // Filter threat intelligence indicators within the lookback period
    | extend IndicatorType = replace(@"\[|\]|\""", "", tostring(split(ObservableKey, ":", 0)))
    | where isnotempty(IndicatorType) and IndicatorType == "url"
    | extend Url = ObservableValue
    | 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 IsActive == true and ValidUntil > now() // Filter for active indicators that haven't expired
    | where EmailUrlInfo_TimeGenerated < ValidUntil // Ensure email info was generated before the indicator expired
    | summarize EmailUrlInfo_TimeGenerated = arg_max(EmailUrlInfo_TimeGenerated, *) by Id, Url // Get the latest email info for each indicator
    | extend Description = tostring(parse_json(Data).description)
    | extend ActivityGroupNames = extract("ActivityGroup:([^,]+)", 1, tostring(parse_json(Data).labels))
    | project EmailUrlInfo_TimeGenerated, Description, ActivityGroupNames, Id, ValidUntil, Confidence, 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
    | extend IndicatorId = tostring(split(IndicatorId, "--")[2]);
    TI_Domains
    | project-reorder *, Active, Tags, TrafficLightProtocolLevel, DomainName, Url, Type
    | 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
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: RecipientEmailAddress
      - identifier: Name
        columnName: Name
      - identifier: UPNSuffix
        columnName: UPNSuffix
  - entityType: URL
    fieldMappings:
      - identifier: Url
        columnName: Url
version: 1.0.3
kind: Scheduled