Detection rules › Kusto
ProofpointPOD - Multiple large emails to the same recipient
'Detects when multiple emails with large size where sent to the same recipient.'
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Exfiltration | T1567 Exfiltration Over Web Service |
Rule body kusto
id: d1aba9a3-5ab1-45ef-8ed4-da57dc3c0d32
name: ProofpointPOD - Multiple large emails to the same recipient
description: |
'Detects when multiple emails with large size where sent to the same recipient.'
severity: Medium
status: Available
requiredDataConnectors:
- connectorId: ProofpointPOD
dataTypes:
- ProofpointPOD_message_CL
queryFrequency: 30m
queryPeriod: 30m
triggerOperator: gt
triggerThreshold: 0
tactics:
- Exfiltration
relevantTechniques:
- T1567
query: |
let lbtime = 30m;
let msgthreshold = 3;
let msgszthreshold = 3000000;
ProofpointPOD
| where TimeGenerated > ago(lbtime)
| where EventType == 'message'
| where NetworkDirection == 'outbound'
| where NetworkBytes > msgszthreshold
| summarize count() by SrcUserUpn, DstUserUpn
| where count_ > msgthreshold
| extend AccountCustomEntity = SrcUserUpn
entityMappings:
- entityType: Account
fieldMappings:
- identifier: FullName
columnName: AccountCustomEntity
version: 1.0.1
kind: Scheduled
Stages and Predicates
Parameters
let lbtime = 30m;
let msgthreshold = 3;
let msgszthreshold = 3000000;
Stage 1: source
ProofpointPOD
Stage 2: where
| where TimeGenerated > ago(lbtime)
Stage 3: where
| where EventType == 'message'
Stage 4: where
| where NetworkDirection == 'outbound'
Stage 5: where
| where NetworkBytes > msgszthreshold
Stage 6: summarize
| summarize count() by SrcUserUpn, DstUserUpn
Stage 7: where
| where count_ > msgthreshold
Stage 8: extend
| extend AccountCustomEntity = SrcUserUpn
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
EventType | eq |
|
NetworkBytes | gt |
|
NetworkDirection | eq |
|
count_ | gt |
|
Output fields
Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.
| Field | Source |
|---|---|
DstUserUpn | summarize |
SrcUserUpn | summarize |
AccountCustomEntity | extend |