Detection rules › Kusto
Trend Micro CAS - Ransomware outbreak
'Triggeres when ransomware was detected on several accounts.'
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Impact | T1486 Data Encrypted for Impact |
Rule body kusto
id: 38e043ce-a1fd-497b-8d4f-ce5ca2db90cd
name: Trend Micro CAS - Ransomware outbreak
description: |
'Triggeres when ransomware was detected on several accounts.'
severity: High
status: Available
requiredDataConnectors:
- connectorId: TrendMicroCAS
dataTypes:
- TrendMicroCAS
queryFrequency: 10m
queryPeriod: 10m
triggerOperator: gt
triggerThreshold: 0
tactics:
- Impact
relevantTechniques:
- T1486
query: |
TrendMicroCAS
| where EventType =~ 'ransomware'
| summarize count() by DstUserName, bin(TimeGenerated, 2m)
| where count_ >= 2
| extend AccountCustomEntity = DstUserName
entityMappings:
- entityType: Account
fieldMappings:
- identifier: Name
columnName: AccountCustomEntity
version: 1.0.1
kind: Scheduled
Stages and Predicates
Stage 1: source
TrendMicroCAS
Stage 2: where
| where EventType =~ 'ransomware'
Stage 3: summarize
| summarize count() by DstUserName, bin(TimeGenerated, 2m)
Stage 4: where
| where count_ >= 2
Stage 5: extend
| extend AccountCustomEntity = DstUserName
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.
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 |
|---|---|
DstUserName | summarize |
AccountCustomEntity | extend |