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Detection rules › Kusto

Critical Severity Incident

This is a third-party alert feed, not a detection over modeled telemetry. The vendor product raised the finding; this rule forwards it into the SIEM. It is searchable for reference but is excluded from the detection-rule browse and the ATT&CK coverage matrix.

Status
available
Severity
high
Time window
10m
Group by
id
Source
github.com/Azure/Azure-Sentinel

'Triggers an incident for every Morphisec alert whose attacks severity is critical.'

MITRE ATT&CK coverage

TacticTechniques
ExecutionT1059 Command and Scripting Interpreter, T1204 User Execution

Rule body kusto

id: 4f1c9e6e-8b6b-4d2a-9f3e-123456789abc
name: Critical Severity Incident
description: |
  'Triggers an incident for every Morphisec alert whose attacks severity is critical.'
severity: High
status: Available
requiredDataConnectors:
  - connectorId: MorphisecCCF
    dataTypes:
      - Morphisec
queryFrequency: 10m
queryPeriod: 10m
triggerOperator: gt
triggerThreshold: 0
suppressionDuration: 5h
suppressionEnabled: false
tactics:
  - Execution
  - DefenseEvasion
relevantTechniques:
  - T1059
  - T1204
query: |
  MorphisecAlerts_CL
  | where threatMessageArrivalTime >= ago(10m)
  | where attackSeverity == "CRITICAL"
  | summarize arg_max(threatMessageArrivalTime, *) by id
entityMappings:
  - entityType: Host
    fieldMappings:
      - identifier: HostName
        columnName: hostname
  - entityType: Process
    fieldMappings:
      - identifier: CommandLine
        columnName: processCommandLine
eventGroupingSettings:
  aggregationKind: SingleAlert
incidentConfiguration:
  createIncident: true
  groupingConfiguration:
    enabled: false
    reopenClosedIncident: false
    lookbackDuration: 5h
    matchingMethod: AllEntities
alertDetailsOverride:
  alertDisplayNameFormat: "Critical alert detected: {{threatSubType}}"
version: 1.0.0
kind: Scheduled

Stages and Predicates

Stage 1: source

MorphisecAlerts_CL

Stage 2: where

| where threatMessageArrivalTime >= ago(10m)

Stage 3: where

| where attackSeverity == "CRITICAL"

Stage 4: summarize

| summarize arg_max(threatMessageArrivalTime, *) by id

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.

FieldKindValues
attackSeverityeq
  • CRITICAL transforms: cased

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.

FieldSource
idsummarize