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

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

ARM

{
  "$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/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",
        "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"
    }
  ]
}