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	1.0.1
Arm template	72264f4f-61fb-4f4f-96c4-635571a376c2.json

KQL

MimecastSIEM_CL| where mimecastEventId_s=="mail_ttp_attachment"

YAML

name: Mimecast Secure Email Gateway - Attachment Protect
triggerOperator: gt
queryPeriod: 15m
version: 1.0.1
kind: Scheduled
id: 72264f4f-61fb-4f4f-96c4-635571a376c2
severity: High
triggerThreshold: 0
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/MimecastSEG/Analytic Rules/MimecastSIEM_Attachment.yaml
customDetails:
  MsgId_s: MsgId_s
  sha256: sha256_s
  fileName: fileName_s
requiredDataConnectors:
- dataTypes:
  - MimecastSIEM_CL
  connectorId: MimecastSIEMAPI
eventGroupingSettings:
  aggregationKind: SingleAlert
suppressionDuration: 5h
relevantTechniques:
- T1114
- T1566
- T0865
suppressionEnabled: false
description: Detect threat for mail attachment under the targeted threat protection
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
query: MimecastSIEM_CL| where mimecastEventId_s=="mail_ttp_attachment"
tactics:
- Collection
- Exfiltration
- Discovery
- InitialAccess
- Execution
incidentConfiguration:
  createIncident: true
  groupingConfiguration:
    reopenClosedIncident: false
    matchingMethod: AllEntities
    lookbackDuration: 1d
    enabled: true
queryFrequency: 5m
enabled: true

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_s": "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": "1.0.1",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}