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

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  
relevantTechniques:
- T1567
severity: Medium
tactics:
- Exfiltration
entityMappings:
- entityType: Account
  fieldMappings:
  - identifier: FullName
    columnName: AccountCustomEntity
triggerThreshold: 0
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Proofpoint On demand(POD) Email Security/Analytic Rules/ProofpointPODMultipleArchivedAttachmentsToSameRecipient.yaml
id: bda5a2bd-979b-4828-a91f-27c2a5048f7f
version: 1.0.2
description: |
    'Detects when multiple emails where sent to the same recipient with large archived attachments.'
queryPeriod: 30m
name: ProofpointPOD - Multiple archived attachments to the same recipient
requiredDataConnectors:
- connectorId: ProofpointPOD
  dataTypes:
  - ProofpointPOD_message_CL
status: Available
triggerOperator: gt
queryFrequency: 30m
kind: Scheduled

ARM