Detection rules › Kusto
Bitglass - Multiple files shared with external entity
'Detects when multiple files shared with external entity.'
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Exfiltration | T1567 Exfiltration Over Web Service |
Rule body kusto
id: 09690f9b-33d1-4372-a6aa-eb7d3b3cdebc
name: Bitglass - Multiple files shared with external entity
description: |
'Detects when multiple files shared with external entity.'
severity: Medium
status: Available
requiredDataConnectors:
- connectorId: Bitglass
dataTypes:
- Bitglass
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
- Exfiltration
relevantTechniques:
- T1567
query: |
let threshold = 5;
Bitglass
| where EventType =~ 'cloudaudit'
| where Action =~ 'Action DLPScan'
| where EventMessage has_all ('External', 'Shared', 'DLP')
| summarize f_cnt = makeset(SrcFileName) by User, bin(TimeGenerated, 10m)
| where array_length(f_cnt) >= threshold
| extend AccountCustomEntity = User
entityMappings:
- entityType: Account
fieldMappings:
- identifier: Name
columnName: AccountCustomEntity
version: 1.0.0
kind: Scheduled
Stages and Predicates
Parameters
let threshold = 5;
Stage 1: source
Bitglass
Stage 2: where
| where EventType =~ 'cloudaudit'
Stage 3: where
| where Action =~ 'Action DLPScan'
Stage 4: where
| where EventMessage has_all ('External', 'Shared', 'DLP')
Stage 5: summarize
| summarize f_cnt = makeset(SrcFileName) by User, bin(TimeGenerated, 10m)
Stage 6: where
| where array_length(f_cnt) >= threshold
Stage 7: extend
| extend AccountCustomEntity = User
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 |
|---|---|---|
Action | eq |
|
EventMessage | match |
|
EventType | eq |
|
f_cnt | ge |
|
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 |
|---|---|
User | summarize |
f_cnt | summarize |
AccountCustomEntity | extend |