ProofpointPOD - Multiple archived attachments to the same recipient

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Id	bda5a2bd-979b-4828-a91f-27c2a5048f7f
Rulename	ProofpointPOD - Multiple archived attachments to the same recipient
Description	Detects when multiple emails where sent to the same recipient with large archived attachments.
Severity	Medium
Tactics	Exfiltration
Techniques	T1567
Required data connectors	ProofpointPOD
Kind	Scheduled
Query frequency	30m
Query period	30m
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Proofpoint On demand(POD) Email Security/Analytic Rules/ProofpointPODMultipleArchivedAttachmentsToSameRecipient.yaml
Version	1.0.2
Arm template	bda5a2bd-979b-4828-a91f-27c2a5048f7f.json

KQL

let lbtime = 30m;
let msgthreshold = 3;
let compressedTypes = dynamic(['zip', 'rar', 'tar', 'x-7z-compressed']);
ProofpointPOD
| where TimeGenerated > ago(lbtime)
| where EventType == 'message'
| where NetworkDirection == 'outbound'
| extend attachedMimeType = todynamic(MsgParts)[0]['detectedMime']
| where attachedMimeType has_any (compressedTypes)
| summarize count(), make_set(attachedMimeType) by SrcUserUpn, DstUserUpn
| where count_ > msgthreshold
| extend AccountCustomEntity = SrcUserUpn

YAML

triggerThreshold: 0
requiredDataConnectors:
- connectorId: ProofpointPOD
  dataTypes:
  - ProofpointPOD_message_CL
severity: Medium
queryFrequency: 30m
id: bda5a2bd-979b-4828-a91f-27c2a5048f7f
relevantTechniques:
- T1567
queryPeriod: 30m
name: ProofpointPOD - Multiple archived attachments to the same recipient
status: Available
kind: Scheduled
tactics:
- Exfiltration
triggerOperator: gt
version: 1.0.2
entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: AccountCustomEntity
    identifier: FullName
description: |
    'Detects when multiple emails where sent to the same recipient with large archived attachments.'
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Proofpoint On demand(POD) Email Security/Analytic Rules/ProofpointPODMultipleArchivedAttachmentsToSameRecipient.yaml
query: |
  let lbtime = 30m;
  let msgthreshold = 3;
  let compressedTypes = dynamic(['zip', 'rar', 'tar', 'x-7z-compressed']);
  ProofpointPOD
  | where TimeGenerated > ago(lbtime)
  | where EventType == 'message'
  | where NetworkDirection == 'outbound'
  | extend attachedMimeType = todynamic(MsgParts)[0]['detectedMime']
  | where attachedMimeType has_any (compressedTypes)
  | summarize count(), make_set(attachedMimeType) by SrcUserUpn, DstUserUpn
  | where count_ > msgthreshold
  | extend AccountCustomEntity = SrcUserUpn

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/bda5a2bd-979b-4828-a91f-27c2a5048f7f')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/bda5a2bd-979b-4828-a91f-27c2a5048f7f')]",
      "properties": {
        "alertRuleTemplateName": "bda5a2bd-979b-4828-a91f-27c2a5048f7f",
        "customDetails": null,
        "description": "'Detects when multiple emails where sent to the same recipient with large archived attachments.'\n",
        "displayName": "ProofpointPOD - Multiple archived attachments to the same recipient",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "AccountCustomEntity",
                "identifier": "FullName"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Proofpoint On demand(POD) Email Security/Analytic Rules/ProofpointPODMultipleArchivedAttachmentsToSameRecipient.yaml",
        "query": "let lbtime = 30m;\nlet msgthreshold = 3;\nlet compressedTypes = dynamic(['zip', 'rar', 'tar', 'x-7z-compressed']);\nProofpointPOD\n| where TimeGenerated > ago(lbtime)\n| where EventType == 'message'\n| where NetworkDirection == 'outbound'\n| extend attachedMimeType = todynamic(MsgParts)[0]['detectedMime']\n| where attachedMimeType has_any (compressedTypes)\n| summarize count(), make_set(attachedMimeType) by SrcUserUpn, DstUserUpn\n| where count_ > msgthreshold\n| extend AccountCustomEntity = SrcUserUpn\n",
        "queryFrequency": "PT30M",
        "queryPeriod": "PT30M",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Exfiltration"
        ],
        "techniques": [
          "T1567"
        ],
        "templateVersion": "1.0.2",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}