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ThreatConnect TI map Email entity to OfficeActivity

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Id4f7ade3e-7121-5274-83ea-d7ed22a01fea
RulenameThreatConnect TI map Email entity to OfficeActivity
DescriptionIdentifies a match in OfficeActivity table from any Email IOC from ThreatConnect TI
SeverityMedium
TacticsImpact
Required data connectorsMicrosoftDefenderThreatIntelligence
Office365
ThreatIntelligence
ThreatIntelligenceTaxii
KindScheduled
Query frequency1h
Query period14d
Trigger threshold0
Trigger operatorgt
Source Urihttps://github.com/Azure/Azure-Sentinel/blob/master/Solutions/ThreatConnect/Analytic Rules/ThreatConnect_EmailEntity_OfficeActivity.yaml
Version1.2.4
Arm template4f7ade3e-7121-5274-83ea-d7ed22a01fea.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)
  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
  | where ExpirationDateTime > now() and Active == true
// Filter out non ThreatConnect TI Sources
| where SourceSystem startswith "ThreatConnect-"
//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 == $right.UserId
| where OfficeActivity_TimeGenerated < ExpirationDateTime
| summarize OfficeActivity_TimeGenerated = arg_max(OfficeActivity_TimeGenerated, *) by IndicatorId, UserId
| project OfficeActivity_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, ExpirationDateTime, ConfidenceScore,
EmailSenderName, EmailRecipient, EmailSourceDomain, EmailSourceIpAddress, EmailSubject, FileHashValue, FileHashType, UserId, ClientIP, Operation, UserType, RecordType, OfficeWorkload, Parameters
| extend Name = tostring(split(UserId, '@', 0)[0]), UPNSuffix = tostring(split(UserId, '@', 1)[0])
| extend timestamp = OfficeActivity_TimeGenerated
triggerOperator: gt
tactics:
- Impact
queryPeriod: 14d
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/ThreatConnect/Analytic Rules/ThreatConnect_EmailEntity_OfficeActivity.yaml
queryFrequency: 1h
description: |
    'Identifies a match in OfficeActivity table from any Email IOC from ThreatConnect TI'
kind: Scheduled
version: 1.2.4
triggerThreshold: 0
severity: Medium
requiredDataConnectors:
- dataTypes:
  - OfficeActivity
  connectorId: Office365
- dataTypes:
  - ThreatIntelligenceIndicator
  connectorId: ThreatIntelligence
- dataTypes:
  - ThreatIntelligenceIndicator
  connectorId: ThreatIntelligenceTaxii
- dataTypes:
  - ThreatIntelligenceIndicator
  connectorId: MicrosoftDefenderThreatIntelligence
id: 4f7ade3e-7121-5274-83ea-d7ed22a01fea
entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: Name
    identifier: Name
  - columnName: UPNSuffix
    identifier: UPNSuffix
- entityType: IP
  fieldMappings:
  - columnName: ClientIP
    identifier: Address
- entityType: URL
  fieldMappings:
  - columnName: Url
    identifier: Url
name: ThreatConnect TI map Email entity to OfficeActivity
query: |
  let dt_lookBack = 1h;
  let ioc_lookBack = 14d;
  let emailregex = @'^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$';
  ThreatIntelligenceIndicator
    | where TimeGenerated >= ago(ioc_lookBack)
    | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId
    | where ExpirationDateTime > now() and Active == true
  // Filter out non ThreatConnect TI Sources
  | where SourceSystem startswith "ThreatConnect-"
  //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 == $right.UserId
  | where OfficeActivity_TimeGenerated < ExpirationDateTime
  | summarize OfficeActivity_TimeGenerated = arg_max(OfficeActivity_TimeGenerated, *) by IndicatorId, UserId
  | project OfficeActivity_TimeGenerated, Description, ActivityGroupNames, IndicatorId, ThreatType, Url, ExpirationDateTime, ConfidenceScore,
  EmailSenderName, EmailRecipient, EmailSourceDomain, EmailSourceIpAddress, EmailSubject, FileHashValue, FileHashType, UserId, ClientIP, Operation, UserType, RecordType, OfficeWorkload, Parameters
  | extend Name = tostring(split(UserId, '@', 0)[0]), UPNSuffix = tostring(split(UserId, '@', 1)[0])
  | extend timestamp = OfficeActivity_TimeGenerated  
{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2023-02-01-preview",
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/4f7ade3e-7121-5274-83ea-d7ed22a01fea')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/4f7ade3e-7121-5274-83ea-d7ed22a01fea')]",
      "properties": {
        "alertRuleTemplateName": "4f7ade3e-7121-5274-83ea-d7ed22a01fea",
        "customDetails": null,
        "description": "'Identifies a match in OfficeActivity table from any Email IOC from ThreatConnect TI'\n",
        "displayName": "ThreatConnect TI map Email entity to OfficeActivity",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "Name",
                "identifier": "Name"
              },
              {
                "columnName": "UPNSuffix",
                "identifier": "UPNSuffix"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "ClientIP",
                "identifier": "Address"
              }
            ]
          },
          {
            "entityType": "URL",
            "fieldMappings": [
              {
                "columnName": "Url",
                "identifier": "Url"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/ThreatConnect/Analytic Rules/ThreatConnect_EmailEntity_OfficeActivity.yaml",
        "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)\n  | summarize LatestIndicatorTime = arg_max(TimeGenerated, *) by IndicatorId\n  | where ExpirationDateTime > now() and Active == true\n// Filter out non ThreatConnect TI Sources\n| where SourceSystem startswith \"ThreatConnect-\"\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 Name = tostring(split(UserId, '@', 0)[0]), UPNSuffix = tostring(split(UserId, '@', 1)[0])\n| extend timestamp = OfficeActivity_TimeGenerated\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "P14D",
        "severity": "Medium",
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Impact"
        ],
        "templateVersion": "1.2.4",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}