Detection rules › Kusto
Box - Item shared to external entity
'Detects when an item was shared to external entity.'
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Exfiltration | T1537 Transfer Data to Cloud Account |
Rule body kusto
id: 3b803560-f8a6-4db4-89cb-617d89724ba1
name: Box - Item shared to external entity
description: |
'Detects when an item was shared to external entity.'
severity: Medium
status: Available
requiredDataConnectors:
- connectorId: BoxDataConnector
dataTypes:
- BoxEvents_CL
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
- Exfiltration
relevantTechniques:
- T1537
query: |
BoxEvents
| where EventType =~ 'COLLABORATION_INVITE'
| extend corp_domain = tolower(extract(@'@(.*)', 1, SrcUserUpn))
| extend accessibleby_domain = tolower(extract(@'@(.*)', 1, AccessibleByLogin))
| where corp_domain != accessibleby_domain
| extend AccountCustomEntity = SrcUserUpn
entityMappings:
- entityType: Account
fieldMappings:
- identifier: FullName
columnName: AccountCustomEntity
version: 1.0.0
kind: Scheduled
Stages and Predicates
Stage 1: source
BoxEvents
Stage 2: where
| where EventType =~ 'COLLABORATION_INVITE'
Stage 3: extend
| extend corp_domain = tolower(extract(@'@(.*)', 1, SrcUserUpn))
Stage 4: extend
| extend accessibleby_domain = tolower(extract(@'@(.*)', 1, AccessibleByLogin))
Stage 5: where
| where corp_domain != accessibleby_domain
Stage 6: 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 |
|
corp_domain | ne |
|
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 |
|---|---|
corp_domain | extend |
accessibleby_domain | extend |
AccountCustomEntity | extend |