ProofpointPOD - Multiple protected emails to unknown recipient

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Id	f8127962-7739-4211-a4a9-390a7a00e91f
Rulename	ProofpointPOD - Multiple protected emails to unknown recipient
Description	Detects when multiple protected messages where sent to early not seen recipient.
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/ProofpointPODMultipleProtectedEmailsToUnknownRecipient.yaml
Version	1.1.1
Arm template	f8127962-7739-4211-a4a9-390a7a00e91f.json

KQL

let lbtime = 30m;
let lbperiod = 14d;
let knownrecipients = ProofpointPOD
| where TimeGenerated > ago(lbperiod)
| where EventType == 'message'
| where NetworkDirection == 'outbound'
| where SrcUserUpn != ''
| where array_length(todynamic(DstUserUpn)) == 1
| summarize recipients = make_set(tostring(todynamic(DstUserUpn)[0])) by SrcUserUpn
| extend commcol = SrcUserUpn;
ProofpointPOD
| where TimeGenerated between (ago(lbtime) .. now())
| where EventType == 'message'
| where NetworkDirection == 'outbound'
| extend isProtected = todynamic(MsgParts)[0]['isProtected']
| extend mimePgp = todynamic(MsgParts)[0]['detectedMime']
| where isProtected == 'true' or mimePgp == 'application/pgp-encrypted'
| extend DstUserMail = tostring(todynamic(DstUserUpn)[0])
| extend commcol = tostring(todynamic(DstUserUpn)[0])
| join knownrecipients on commcol
| where recipients !contains DstUserMail
| project SrcUserUpn, DstUserMail
| extend AccountCustomEntity = SrcUserUpn

YAML

description: |
    'Detects when multiple protected messages where sent to early not seen recipient.'
kind: Scheduled
tactics:
- Exfiltration
requiredDataConnectors:
- connectorId: ProofpointPOD
  dataTypes:
  - ProofpointPOD_message_CL
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Proofpoint On demand(POD) Email Security/Analytic Rules/ProofpointPODMultipleProtectedEmailsToUnknownRecipient.yaml
severity: Medium
name: ProofpointPOD - Multiple protected emails to unknown recipient
triggerThreshold: 0
queryPeriod: 30m
query: |
  let lbtime = 30m;
  let lbperiod = 14d;
  let knownrecipients = ProofpointPOD
  | where TimeGenerated > ago(lbperiod)
  | where EventType == 'message'
  | where NetworkDirection == 'outbound'
  | where SrcUserUpn != ''
  | where array_length(todynamic(DstUserUpn)) == 1
  | summarize recipients = make_set(tostring(todynamic(DstUserUpn)[0])) by SrcUserUpn
  | extend commcol = SrcUserUpn;
  ProofpointPOD
  | where TimeGenerated between (ago(lbtime) .. now())
  | where EventType == 'message'
  | where NetworkDirection == 'outbound'
  | extend isProtected = todynamic(MsgParts)[0]['isProtected']
  | extend mimePgp = todynamic(MsgParts)[0]['detectedMime']
  | where isProtected == 'true' or mimePgp == 'application/pgp-encrypted'
  | extend DstUserMail = tostring(todynamic(DstUserUpn)[0])
  | extend commcol = tostring(todynamic(DstUserUpn)[0])
  | join knownrecipients on commcol
  | where recipients !contains DstUserMail
  | project SrcUserUpn, DstUserMail
  | extend AccountCustomEntity = SrcUserUpn  
relevantTechniques:
- T1567
id: f8127962-7739-4211-a4a9-390a7a00e91f
queryFrequency: 30m
status: Available
triggerOperator: gt
version: 1.1.1
entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: AccountCustomEntity
    identifier: FullName

ARM