Preview - TI map Email entity to Cloud App Events

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Id	47b9bb10-d216-4359-8cef-08ca2c67e5be
Rulename	Preview - TI map Email entity to Cloud App Events
Description	Identifies compromises and attacks and detect malicious activities in one’s email entity from TI
Severity	Medium
Tactics	InitialAccess
Techniques	T1566
Required data connectors	MicrosoftDefenderThreatIntelligence MicrosoftThreatProtection
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_CloudAppEvents.yaml
Version	1.0.3
Arm template	47b9bb10-d216-4359-8cef-08ca2c67e5be.json

KQL

let dt_lookBack = 10d;
let ioc_lookBack = 30d;
let emailregex = @'^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$';
ThreatIntelligenceIndicator
  | where TimeGenerated >= ago(ioc_lookBack)
  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
  | where Active == true and ExpirationDateTime > now()
  | where isnotempty(EmailSenderAddress)
  | join kind=innerunique (CloudAppEvents
| extend User_Id = tostring(RawEventData.UserId)
| where isnotempty(User_Id)
| where TimeGenerated >= ago(dt_lookBack) and isnotempty(Application)
| extend CloudAppEvents_TimeGenerated = TimeGenerated 
| where User_Id matches regex emailregex) on $left.EmailSenderAddress == $right.User_Id
| where CloudAppEvents_TimeGenerated < ExpirationDateTime
| summarize CloudAppEvents_TimeGenerated = argmax(CloudAppEvents_TimeGenerated, *) by IndicatorId, User_Id
| extend Name = tostring(split(User_Id, '@', 0)[0]), UPNSuffix = tostring(split(User_Id, '@', 1)[0])
| extend timestamp = CloudAppEvents_TimeGenerated

YAML

queryPeriod: 14d
query: |
  let dt_lookBack = 10d;
  let ioc_lookBack = 30d;
  let emailregex = @'^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$';
  ThreatIntelligenceIndicator
    | where TimeGenerated >= ago(ioc_lookBack)
    | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
    | where Active == true and ExpirationDateTime > now()
    | where isnotempty(EmailSenderAddress)
    | join kind=innerunique (CloudAppEvents
  | extend User_Id = tostring(RawEventData.UserId)
  | where isnotempty(User_Id)
  | where TimeGenerated >= ago(dt_lookBack) and isnotempty(Application)
  | extend CloudAppEvents_TimeGenerated = TimeGenerated 
  | where User_Id matches regex emailregex) on $left.EmailSenderAddress == $right.User_Id
  | where CloudAppEvents_TimeGenerated < ExpirationDateTime
  | summarize CloudAppEvents_TimeGenerated = argmax(CloudAppEvents_TimeGenerated, *) by IndicatorId, User_Id
  | extend Name = tostring(split(User_Id, '@', 0)[0]), UPNSuffix = tostring(split(User_Id, '@', 1)[0])
  | extend timestamp = CloudAppEvents_TimeGenerated  
name: Preview - TI map Email entity to Cloud App Events
entityMappings:
- fieldMappings:
  - columnName: Name
    identifier: DisplayName
  - columnName: User_Id
    identifier: FullName
  - columnName: UPNSuffix
    identifier: UPNSuffix
  entityType: Account
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat Intelligence/Analytic Rules/EmailEntity_CloudAppEvents.yaml
requiredDataConnectors:
- connectorId: MicrosoftThreatProtection
  dataTypes:
  - CloudAppEvents
- connectorId: MicrosoftDefenderThreatIntelligence
  dataTypes:
  - ThreatIntelligenceIndicator
description: |
    'Identifies compromises and attacks and detect malicious activities in one's email entity from TI'
kind: Scheduled
version: 1.0.3
queryFrequency: 1h
severity: Medium
relevantTechniques:
- T1566
triggerOperator: gt
triggerThreshold: 0
tactics:
- InitialAccess
id: 47b9bb10-d216-4359-8cef-08ca2c67e5be

ARM