TI map Email entity to AzureActivity

let dt_lookBack = 1h;
let ioc_lookBack = 14d;
let emailregex = @'^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$';
ThreatIntelligenceIndicator
//Filtering the table for Email related IOCs
| where isnotempty(EmailSenderAddress)
| where TimeGenerated >= ago(ioc_lookBack)
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
| where Active == true and ExpirationDateTime > now()
// using innerunique to keep perf fast and result set low, we only need one match to indicate potential malicious activity that needs to be investigated
| join kind=innerunique (
    AzureActivity | where TimeGenerated >= ago(dt_lookBack) and isnotempty(Caller)
    | extend Caller = tolower(Caller)
    | where Caller matches regex emailregex
    | extend AzureActivity_TimeGenerated = TimeGenerated
)
on $left.EmailSenderAddress == $right.Caller
| where AzureActivity_TimeGenerated < ExpirationDateTime
| summarize AzureActivity_TimeGenerated = arg_max(AzureActivity_TimeGenerated, *) by IndicatorId, Caller
| project AzureActivity_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, Url, EmailSenderName, EmailRecipient,
EmailSourceDomain, EmailSourceIpAddress, EmailSubject, FileHashValue, FileHashType, Caller, Level, CallerIpAddress, CategoryValue, OperationNameValue, ActivityStatusValue,
ResourceGroup, SubscriptionId
| extend Name = tostring(split(Caller, '@', 0)[0]), UPNSuffix = tostring(split(Caller, '@', 1)[0])
| extend timestamp = AzureActivity_TimeGenerated

description: |
    'Identifies a match in AzureActivity table from any Email IOC from TI'
query: |
  let dt_lookBack = 1h;
  let ioc_lookBack = 14d;
  let emailregex = @'^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$';
  ThreatIntelligenceIndicator
  //Filtering the table for Email related IOCs
  | where isnotempty(EmailSenderAddress)
  | where TimeGenerated >= ago(ioc_lookBack)
  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
  | where Active == true and ExpirationDateTime > now()
  // using innerunique to keep perf fast and result set low, we only need one match to indicate potential malicious activity that needs to be investigated
  | join kind=innerunique (
      AzureActivity | where TimeGenerated >= ago(dt_lookBack) and isnotempty(Caller)
      | extend Caller = tolower(Caller)
      | where Caller matches regex emailregex
      | extend AzureActivity_TimeGenerated = TimeGenerated
  )
  on $left.EmailSenderAddress == $right.Caller
  | where AzureActivity_TimeGenerated < ExpirationDateTime
  | summarize AzureActivity_TimeGenerated = arg_max(AzureActivity_TimeGenerated, *) by IndicatorId, Caller
  | project AzureActivity_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, Url, EmailSenderName, EmailRecipient,
  EmailSourceDomain, EmailSourceIpAddress, EmailSubject, FileHashValue, FileHashType, Caller, Level, CallerIpAddress, CategoryValue, OperationNameValue, ActivityStatusValue,
  ResourceGroup, SubscriptionId
  | extend Name = tostring(split(Caller, '@', 0)[0]), UPNSuffix = tostring(split(Caller, '@', 1)[0])
  | extend timestamp = AzureActivity_TimeGenerated  
requiredDataConnectors:
- connectorId: AzureActivity
  dataTypes:
  - AzureActivity
- connectorId: ThreatIntelligence
  dataTypes:
  - ThreatIntelligenceIndicator
- connectorId: ThreatIntelligenceTaxii
  dataTypes:
  - ThreatIntelligenceIndicator
- connectorId: MicrosoftDefenderThreatIntelligence
  dataTypes:
  - ThreatIntelligenceIndicator
entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: Caller
    identifier: FullName
  - columnName: Name
    identifier: Name
  - columnName: UPNSuffix
    identifier: UPNSuffix
- entityType: IP
  fieldMappings:
  - columnName: CallerIpAddress
    identifier: Address
- entityType: URL
  fieldMappings:
  - columnName: Url
    identifier: Url
triggerThreshold: 0
tactics:
- InitialAccess
queryPeriod: 14d
triggerOperator: gt
id: cca3b4d9-ac39-4109-8b93-65bb284003e6
relevantTechniques:
- T1566
severity: Medium
name: TI map Email entity to AzureActivity
kind: Scheduled
queryFrequency: 1h
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat Intelligence/Analytic Rules/EmailEntity_AzureActivity.yaml
version: 1.2.7