Mimecast Secure Email Gateway - Attachment Protect

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Id	72264f4f-61fb-4f4f-96c4-635571a376c2
Rulename	Mimecast Secure Email Gateway - Attachment Protect
Description	Detect threat for mail attachment under the targeted threat protection
Severity	High
Tactics	Collection Exfiltration Discovery InitialAccess Execution
Techniques	T1114 T1566 T0865
Required data connectors	MimecastSIEMAPI
Kind	Scheduled
Query frequency	5m
Query period	15m
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/MimecastSEG/Analytic Rules/MimecastSIEM_Attachment.yaml
Version	1.0.0
Arm template	72264f4f-61fb-4f4f-96c4-635571a376c2.json

KQL

MimecastSIEM_CL| where mimecastEventId_s=="mail_ttp_attachment"

YAML

entityMappings:
- entityType: MailMessage
  fieldMappings:
  - columnName: Sender_s
    identifier: Sender
  - columnName: Recipient_s
    identifier: Recipient
  - columnName: Subject_s
    identifier: Subject
- entityType: IP
  fieldMappings:
  - columnName: IP_s
    identifier: Address
tactics:
- Collection
- Exfiltration
- Discovery
- InitialAccess
- Execution
triggerOperator: gt
description: Detect threat for mail attachment under the targeted threat protection
requiredDataConnectors:
- connectorId: MimecastSIEMAPI
  dataTypes:
  - MimecastSIEM_CL
relevantTechniques:
- T1114
- T1566
- T0865
version: 1.0.0
id: 72264f4f-61fb-4f4f-96c4-635571a376c2
suppressionDuration: 5h
customDetails:
  sha256: sha256_s
  fileName: fileName_s
  MsgId: MsgId_s
queryPeriod: 15m
kind: Scheduled
enabled: true
suppressionEnabled: false
triggerThreshold: 0
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/MimecastSEG/Analytic Rules/MimecastSIEM_Attachment.yaml
incidentConfiguration:
  groupingConfiguration:
    enabled: true
    lookbackDuration: 1d
    reopenClosedIncident: false
    matchingMethod: AllEntities
  createIncident: true
eventGroupingSettings:
  aggregationKind: SingleAlert
queryFrequency: 5m
severity: High
name: Mimecast Secure Email Gateway - Attachment Protect
query: MimecastSIEM_CL| where mimecastEventId_s=="mail_ttp_attachment"

ARM

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2024-01-01-preview",
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/72264f4f-61fb-4f4f-96c4-635571a376c2')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/72264f4f-61fb-4f4f-96c4-635571a376c2')]",
      "properties": {
        "alertRuleTemplateName": "72264f4f-61fb-4f4f-96c4-635571a376c2",
        "customDetails": {
          "fileName": "fileName_s",
          "MsgId": "MsgId_s",
          "sha256": "sha256_s"
        },
        "description": "Detect threat for mail attachment under the targeted threat protection",
        "displayName": "Mimecast Secure Email Gateway - Attachment Protect",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "MailMessage",
            "fieldMappings": [
              {
                "columnName": "Sender_s",
                "identifier": "Sender"
              },
              {
                "columnName": "Recipient_s",
                "identifier": "Recipient"
              },
              {
                "columnName": "Subject_s",
                "identifier": "Subject"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "IP_s",
                "identifier": "Address"
              }
            ]
          }
        ],
        "eventGroupingSettings": {
          "aggregationKind": "SingleAlert"
        },
        "incidentConfiguration": {
          "createIncident": true,
          "groupingConfiguration": {
            "enabled": true,
            "lookbackDuration": "P1D",
            "matchingMethod": "AllEntities",
            "reopenClosedIncident": false
          }
        },
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/MimecastSEG/Analytic Rules/MimecastSIEM_Attachment.yaml",
        "query": "MimecastSIEM_CL| where mimecastEventId_s==\"mail_ttp_attachment\"",
        "queryFrequency": "PT5M",
        "queryPeriod": "PT15M",
        "severity": "High",
        "subTechniques": [],
        "suppressionDuration": "PT5H",
        "suppressionEnabled": false,
        "tactics": [
          "Collection",
          "Discovery",
          "Execution",
          "Exfiltration",
          "InitialAccess"
        ],
        "techniques": [
          "T1114",
          "T1566"
        ],
        "templateVersion": "1.0.0",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}