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Detection rules › Kusto

vArmour AppController - SMB Realm Traversal

Status
available
Severity
medium
Time window
1h
Source
github.com/Azure/Azure-Sentinel

'Detects when SMB traffic crosses Production and Non-Production Realms. Possible network share discovery or lateral tool transfer across realms'

MITRE ATT&CK coverage

TacticTechniques
DiscoveryT1135 Network Share Discovery
Lateral MovementT1570 Lateral Tool Transfer

Rule body kusto

id: a36de6c3-3198-4d37-92ae-e19e36712c2e
name: vArmour AppController - SMB Realm Traversal
description: |
  'Detects when SMB traffic crosses Production and Non-Production Realms. Possible network share discovery or lateral tool transfer across realms'
severity: Medium
status: Available
requiredDataConnectors:
  - connectorId: vArmourAC
    dataTypes:
      - CommonSecurityLog
  - connectorId: vArmourACAma
    dataTypes:
      - CommonSecurityLog
  - connectorId: CefAma
    dataTypes:
      - CommonSecurityLog
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - Discovery
  - LateralMovement
relevantTechniques:
  - T1135
  - T1570
query: |
  CommonSecurityLog
  | where DeviceVendor == "vArmour"
  | where DeviceProduct == "AC"
  | where Activity == "POLICY_VIOLATION"
  | extend PolicyName = extract("(SMB_REALM_TRAVERSAL\\w+{.*})", 1, DeviceCustomString1)
entityMappings:
  - entityType: Host
    fieldMappings:
      - identifier: HostName
        columnName: DestinationHostName
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: SourceIP
version: 1.0.2
kind: Scheduled

Stages and Predicates

Stage 1: source

CommonSecurityLog

Stage 2: where

| where DeviceVendor == "vArmour"

Stage 3: where

| where DeviceProduct == "AC"

Stage 4: where

| where Activity == "POLICY_VIOLATION"

Stage 5: extend

| extend PolicyName = extract("(SMB_REALM_TRAVERSAL\\w+{.*})", 1, DeviceCustomString1)

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
Activityeq
  • POLICY_VIOLATION transforms: cased
DeviceProducteq
  • AC transforms: cased
DeviceVendoreq
  • vArmour 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
PolicyNameextend