Detection rules › Kusto
ProofpointPOD - Multiple archived attachments to the same recipient
'Detects when multiple emails where sent to the same recipient with large archived attachments.'
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Exfiltration |
Rule body
id: bda5a2bd-979b-4828-a91f-27c2a5048f7f
name: 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
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 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
entityMappings:
- entityType: Account
fieldMappings:
- identifier: FullName
columnName: AccountCustomEntity
version: 1.0.2
kind: Scheduled
Stages and Predicates
Parameters
let lbtime = 30m;
let msgthreshold = 3;
let compressedTypes = dynamic(['zip', 'rar', 'tar', 'x-7z-compressed']);
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: extend
| extend attachedMimeType = todynamic(MsgParts)[0]['detectedMime']
Stage 6: where
| where attachedMimeType has_any (compressedTypes)
Stage 7: summarize
| summarize count(), make_set(attachedMimeType) by SrcUserUpn, DstUserUpn
Stage 8: where
| where count_ > msgthreshold
Stage 9: extend
| extend AccountCustomEntity = SrcUserUpn
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
EventType | eq |
| field:"EventType" kind:eq value:"message" |
NetworkDirection | eq |
| field:"NetworkDirection" kind:eq value:"outbound" |
attachedMimeType | match |
| field:"attachedMimeType" kind:match |
count_ | gt |
| field:"count_" kind:gt value:"3" |
Output fields
These fields are emitted when the rule matches.
| Field | Source |
|---|---|
DstUserUpn | summarize |
SrcUserUpn | summarize |
AccountCustomEntity | extend |