TI map Email entity to EmailEvents

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Id	11f7c6e3-f066-4b3c-9a81-b487ec0a6873
Rulename	TI map Email entity to EmailEvents
Description	Identifies a match in EmailEvents table from any Email IOC from TI
Severity	Medium
Tactics	InitialAccess
Techniques	T1566
Required data connectors	MicrosoftDefenderThreatIntelligence Office365 ThreatIntelligence ThreatIntelligenceTaxii
Kind	Scheduled
Query frequency	1h
Query period	14d
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat Intelligence/Analytic Rules/EmailEntity_EmailEvents.yaml
Version	1.0.2
Arm template	11f7c6e3-f066-4b3c-9a81-b487ec0a6873.json

KQL

let dt_lookBack = 1h;
let ioc_lookBack = 14d;
let EmailEvents_ = materialize(EmailEvents | where isnotempty(RecipientEmailAddress) and isnotempty(SenderFromAddress) and TimeGenerated >= ago(dt_lookBack) and DeliveryAction !has "Blocked" | project-rename  EmailEvents_TimeGenerated = TimeGenerated | extend SenderFromAddress = tolower(SenderFromAddress) | extend RecipientEmailAddress = tolower(RecipientEmailAddress));
let SenderAddresses = EmailEvents_ | distinct  SenderFromAddress | summarize make_list(SenderFromAddress);
let RecipientAddresses = EmailEvents_ | distinct  RecipientEmailAddress | summarize make_list(RecipientEmailAddress);
let TI = materialize(ThreatIntelligenceIndicator
| where TimeGenerated >= ago(ioc_lookBack)
| where isnotempty(EmailSenderAddress)
| extend TI_EmailAddress = tolower(EmailSenderAddress)
| where TI_EmailAddress in (SenderAddresses) or TI_EmailAddress in (RecipientAddresses)
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
| where Active == true and ExpirationDateTime > now());
(union
  (TI | join kind=innerunique (EmailEvents_) on $left.TI_EmailAddress == $right.SenderFromAddress),
  (TI | join kind=innerunique (EmailEvents_) on $left.TI_EmailAddress == $right.RecipientEmailAddress))
| where EmailEvents_TimeGenerated < ExpirationDateTime
| summarize EmailEvents_TimeGenerated = arg_max(EmailEvents_TimeGenerated, *) by IndicatorId, TI_EmailAddress
| project EmailEvents_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, DomainName, RecipientEmailAddress, SenderFromAddress, Subject, ConfidenceLevel, Url, Type, TI_EmailAddress, TrafficLightProtocolLevel, DeliveryAction, DeliveryLocation, EmailDirection
| extend Name = tostring(split(RecipientEmailAddress, '@', 0)[0]), UPNSuffix = tostring(split(RecipientEmailAddress, '@', 1)[0])
| extend timestamp = EmailEvents_TimeGenerated

YAML

queryPeriod: 14d
query: |
  let dt_lookBack = 1h;
  let ioc_lookBack = 14d;
  let EmailEvents_ = materialize(EmailEvents | where isnotempty(RecipientEmailAddress) and isnotempty(SenderFromAddress) and TimeGenerated >= ago(dt_lookBack) and DeliveryAction !has "Blocked" | project-rename  EmailEvents_TimeGenerated = TimeGenerated | extend SenderFromAddress = tolower(SenderFromAddress) | extend RecipientEmailAddress = tolower(RecipientEmailAddress));
  let SenderAddresses = EmailEvents_ | distinct  SenderFromAddress | summarize make_list(SenderFromAddress);
  let RecipientAddresses = EmailEvents_ | distinct  RecipientEmailAddress | summarize make_list(RecipientEmailAddress);
  let TI = materialize(ThreatIntelligenceIndicator
  | where TimeGenerated >= ago(ioc_lookBack)
  | where isnotempty(EmailSenderAddress)
  | extend TI_EmailAddress = tolower(EmailSenderAddress)
  | where TI_EmailAddress in (SenderAddresses) or TI_EmailAddress in (RecipientAddresses)
  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
  | where Active == true and ExpirationDateTime > now());
  (union
    (TI | join kind=innerunique (EmailEvents_) on $left.TI_EmailAddress == $right.SenderFromAddress),
    (TI | join kind=innerunique (EmailEvents_) on $left.TI_EmailAddress == $right.RecipientEmailAddress))
  | where EmailEvents_TimeGenerated < ExpirationDateTime
  | summarize EmailEvents_TimeGenerated = arg_max(EmailEvents_TimeGenerated, *) by IndicatorId, TI_EmailAddress
  | project EmailEvents_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, ExpirationDateTime, ConfidenceScore, DomainName, RecipientEmailAddress, SenderFromAddress, Subject, ConfidenceLevel, Url, Type, TI_EmailAddress, TrafficLightProtocolLevel, DeliveryAction, DeliveryLocation, EmailDirection
  | extend Name = tostring(split(RecipientEmailAddress, '@', 0)[0]), UPNSuffix = tostring(split(RecipientEmailAddress, '@', 1)[0])
  | extend timestamp = EmailEvents_TimeGenerated  
name: TI map Email entity to EmailEvents
entityMappings:
- fieldMappings:
  - columnName: RecipientEmailAddress
    identifier: FullName
  - columnName: Name
    identifier: Name
  - columnName: UPNSuffix
    identifier: UPNSuffix
  entityType: Account
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat Intelligence/Analytic Rules/EmailEntity_EmailEvents.yaml
requiredDataConnectors:
- connectorId: Office365
  dataTypes:
  - EmailEvents
- connectorId: ThreatIntelligence
  dataTypes:
  - ThreatIntelligenceIndicator
- connectorId: ThreatIntelligenceTaxii
  dataTypes:
  - ThreatIntelligenceIndicator
- connectorId: MicrosoftDefenderThreatIntelligence
  dataTypes:
  - ThreatIntelligenceIndicator
description: |
    'Identifies a match in EmailEvents table from any Email IOC from TI'
kind: Scheduled
version: 1.0.2
queryFrequency: 1h
severity: Medium
relevantTechniques:
- T1566
triggerOperator: gt
triggerThreshold: 0
tactics:
- InitialAccess
id: 11f7c6e3-f066-4b3c-9a81-b487ec0a6873

ARM