Detection rules › Kusto

Ransom Protect User Blocked

Status
available
Severity
high
Source
github.com/Azure/Azure-Sentinel

Detects malicious users blocked by CTERA Ransom Protect AI engine.

MITRE ATT&CK coverage

TacticTechniques
ImpactT1486 Data Encrypted for Impact

Rule body kusto

id: d5d4766b-e547-44da-9d85-48ff393db201
name: Ransom Protect User Blocked
description: 'Detects malicious users blocked by CTERA Ransom Protect AI engine.'
status: Available
severity: High
kind: NRT
requiredDataConnectors:
  - connectorId: CTERA
    dataTypes:
      - Syslog
tactics:
    - Impact
relevantTechniques:
    - T1486
query: |
    Syslog
    | where SyslogMessage contains "Ransom Protect mechanism blocked"
    | extend 
        Portal = extract("portal:(\\w+)", 1, SyslogMessage),
        EdgeFiler = extract("Edge Filer:(\\w+-\\d+)", 1, SyslogMessage),
        IP = extract("IP:([0-9.]+)", 1, SyslogMessage),
        User = extract("user:(\\w+)", 1, SyslogMessage),
        BlockedTime = extract("at ([^ ]+)", 1, SyslogMessage)
    | project TimeGenerated, Portal, EdgeFiler, IP, User, BlockedTime
suppressionDuration: PT5H
suppressionEnabled: false
incidentConfiguration:
    createIncident: true
    groupingConfiguration:
        enabled: false
        reopenClosedIncident: false
        lookbackDuration: PT5H
        matchingMethod: AllEntities
eventGroupingSettings:
    aggregationKind: SingleAlert
alertDetailsOverride: 
    alertnameFormat: 'CTERA Ransom Protect User Blocked'
    alertDescriptionFormat: CTERA Ransom Protect blocked a malicious user at {{TimeGenerated}}.
customDetails:
    EdgeFiler: EdgeFiler
entityMappings:
- entityType: Account
  fieldMappings:
      - identifier: FullName
        columnName: User
- entityType: IP
  fieldMappings:
      - identifier: Address
        columnName: IP
version: 1.0.2

Stages and Predicates

Stage 1: source

Syslog

Stage 2: where

| where SyslogMessage contains "Ransom Protect mechanism blocked"

Stage 3: extend

| extend 
    Portal = extract("portal:(\\w+)", 1, SyslogMessage),
    EdgeFiler = extract("Edge Filer:(\\w+-\\d+)", 1, SyslogMessage),
    IP = extract("IP:([0-9.]+)", 1, SyslogMessage),
    User = extract("user:(\\w+)", 1, SyslogMessage),
    BlockedTime = extract("at ([^ ]+)", 1, SyslogMessage)

Stage 4: project

| project TimeGenerated, Portal, EdgeFiler, IP, User, BlockedTime

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
SyslogMessagecontains
  • Ransom Protect mechanism blocked

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
BlockedTimeproject
EdgeFilerproject
IPproject
Portalproject
TimeGeneratedproject
Userproject