Microsoft Sentinel Analytic Rules
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TI map Email entity to OfficeActivity

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Id4a3f5ed7-8da5-4ce2-af6f-c9ada45060f2
RulenameTI map Email entity to OfficeActivity
DescriptionIdentifies a match in OfficeActivity table from any Email IOC from TI
SeverityMedium
TacticsImpact
Required data connectorsOffice365
ThreatIntelligence
ThreatIntelligenceTaxii
KindScheduled
Query frequency1h
Query period14d
Trigger threshold0
Trigger operatorgt
Source Urihttps://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat Intelligence/Analytic Rules/EmailEntity_OfficeActivity.yaml
Version1.2.2
Arm template4a3f5ed7-8da5-4ce2-af6f-c9ada45060f2.json
Deploy To Azure
let dt_lookBack = 1h;
let ioc_lookBack = 14d;
let emailregex = @'^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$';
ThreatIntelligenceIndicator
| where TimeGenerated >= ago(ioc_lookBack) and ExpirationDateTime > now()
| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
| where Active == true
//Filtering the table for Email related IOCs
| where isnotempty(EmailSenderAddress)
// 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 (
    OfficeActivity | where TimeGenerated >= ago(dt_lookBack) and isnotempty(UserId)
    | where UserId matches regex emailregex
    | extend OfficeActivity_TimeGenerated = TimeGenerated
)
on $left.EmailSenderAddress == $right.UserId
| where OfficeActivity_TimeGenerated < ExpirationDateTime
| summarize OfficeActivity_TimeGenerated = arg_max(OfficeActivity_TimeGenerated, *) by IndicatorId, UserId
| project OfficeActivity_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, ExpirationDateTime, ConfidenceScore,
EmailSenderName, EmailRecipient, EmailSourceDomain, EmailSourceIpAddress, EmailSubject, FileHashValue, FileHashType, UserId, ClientIP, Operation, UserType, RecordType, OfficeWorkload, Parameters
| extend timestamp = OfficeActivity_TimeGenerated, AccountCustomEntity = UserId, IPCustomEntity = ClientIP, URLCustomEntity = Url
triggerThreshold: 0
queryFrequency: 1h
requiredDataConnectors:
- connectorId: Office365
  dataTypes:
  - OfficeActivity
- connectorId: ThreatIntelligence
  dataTypes:
  - ThreatIntelligenceIndicator
- connectorId: ThreatIntelligenceTaxii
  dataTypes:
  - ThreatIntelligenceIndicator
id: 4a3f5ed7-8da5-4ce2-af6f-c9ada45060f2
version: 1.2.2
name: TI map Email entity to OfficeActivity
kind: Scheduled
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat Intelligence/Analytic Rules/EmailEntity_OfficeActivity.yaml
queryPeriod: 14d
severity: Medium
triggerOperator: gt
tactics:
- Impact
query: |
  let dt_lookBack = 1h;
  let ioc_lookBack = 14d;
  let emailregex = @'^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$';
  ThreatIntelligenceIndicator
  | where TimeGenerated >= ago(ioc_lookBack) and ExpirationDateTime > now()
  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
  | where Active == true
  //Filtering the table for Email related IOCs
  | where isnotempty(EmailSenderAddress)
  // 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 (
      OfficeActivity | where TimeGenerated >= ago(dt_lookBack) and isnotempty(UserId)
      | where UserId matches regex emailregex
      | extend OfficeActivity_TimeGenerated = TimeGenerated
  )
  on $left.EmailSenderAddress == $right.UserId
  | where OfficeActivity_TimeGenerated < ExpirationDateTime
  | summarize OfficeActivity_TimeGenerated = arg_max(OfficeActivity_TimeGenerated, *) by IndicatorId, UserId
  | project OfficeActivity_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, ExpirationDateTime, ConfidenceScore,
  EmailSenderName, EmailRecipient, EmailSourceDomain, EmailSourceIpAddress, EmailSubject, FileHashValue, FileHashType, UserId, ClientIP, Operation, UserType, RecordType, OfficeWorkload, Parameters
  | extend timestamp = OfficeActivity_TimeGenerated, AccountCustomEntity = UserId, IPCustomEntity = ClientIP, URLCustomEntity = Url  
entityMappings:
- entityType: Account
  fieldMappings:
  - identifier: FullName
    columnName: AccountCustomEntity
- entityType: IP
  fieldMappings:
  - identifier: Address
    columnName: IPCustomEntity
- entityType: URL
  fieldMappings:
  - identifier: Url
    columnName: URLCustomEntity
description: |
    'Identifies a match in OfficeActivity table from any Email IOC from TI'
{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/4a3f5ed7-8da5-4ce2-af6f-c9ada45060f2')]",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/4a3f5ed7-8da5-4ce2-af6f-c9ada45060f2')]",
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules",
      "kind": "Scheduled",
      "apiVersion": "2022-11-01",
      "properties": {
        "displayName": "TI map Email entity to OfficeActivity",
        "description": "'Identifies a match in OfficeActivity table from any Email IOC from TI'\n",
        "severity": "Medium",
        "enabled": true,
        "query": "let dt_lookBack = 1h;\nlet ioc_lookBack = 14d;\nlet emailregex = @'^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\\.[a-zA-Z0-9-.]+$';\nThreatIntelligenceIndicator\n| where TimeGenerated >= ago(ioc_lookBack) and ExpirationDateTime > now()\n| summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId\n| where Active == true\n//Filtering the table for Email related IOCs\n| where isnotempty(EmailSenderAddress)\n// 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\n| join kind=innerunique (\n    OfficeActivity | where TimeGenerated >= ago(dt_lookBack) and isnotempty(UserId)\n    | where UserId matches regex emailregex\n    | extend OfficeActivity_TimeGenerated = TimeGenerated\n)\non $left.EmailSenderAddress == $right.UserId\n| where OfficeActivity_TimeGenerated < ExpirationDateTime\n| summarize OfficeActivity_TimeGenerated = arg_max(OfficeActivity_TimeGenerated, *) by IndicatorId, UserId\n| project OfficeActivity_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, ExpirationDateTime, ConfidenceScore,\nEmailSenderName, EmailRecipient, EmailSourceDomain, EmailSourceIpAddress, EmailSubject, FileHashValue, FileHashType, UserId, ClientIP, Operation, UserType, RecordType, OfficeWorkload, Parameters\n| extend timestamp = OfficeActivity_TimeGenerated, AccountCustomEntity = UserId, IPCustomEntity = ClientIP, URLCustomEntity = Url\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "P14D",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0,
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Impact"
        ],
        "alertRuleTemplateName": "4a3f5ed7-8da5-4ce2-af6f-c9ada45060f2",
        "customDetails": null,
        "entityMappings": [
          {
            "fieldMappings": [
              {
                "columnName": "AccountCustomEntity",
                "identifier": "FullName"
              }
            ],
            "entityType": "Account"
          },
          {
            "fieldMappings": [
              {
                "columnName": "IPCustomEntity",
                "identifier": "Address"
              }
            ],
            "entityType": "IP"
          },
          {
            "fieldMappings": [
              {
                "columnName": "URLCustomEntity",
                "identifier": "Url"
              }
            ],
            "entityType": "URL"
          }
        ],
        "templateVersion": "1.2.2",
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Threat Intelligence/Analytic Rules/EmailEntity_OfficeActivity.yaml"
      }
    }
  ]
}