Detection rules › Kusto

Unauthorized remote access to the network (Microsoft Defender for IoT)

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

'This alert leverages Defender for IoT to detect unauthorized remote access to network devices, if another device on the network is compromised, target devices can be accessed remotely, increasing the attack surface.'

MITRE ATT&CK coverage

TacticTechniques
Initial AccessT0886 Remote Services
Lateral MovementT0886 Remote Services

Rule body kusto

id: 1ff4fa3d-150b-4c87-b733-26c289af0d49
name: Unauthorized remote access to the network (Microsoft Defender for IoT)
description: |
  'This alert leverages Defender for IoT to detect unauthorized remote access to network devices, if another device on the network is compromised, target devices can be accessed remotely, increasing the attack surface.'
severity: Medium
status: Available
requiredDataConnectors:
  - connectorId: IoT
    dataTypes:
      - SecurityAlert (ASC for IoT)
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - InitialAccess
relevantTechniques:
  - T0886
query: |
  SecurityAlert
  | where ProviderName == "IoTSecurity"
  | where AlertName == "Unauthorized SSH Access"
  | extend ExtendedProperties = parse_json(ExtendedProperties)
  | where tostring(ExtendedProperties.isNew) == "True"
  | extend DeviceId = tostring(ExtendedProperties.DeviceId), 
           SourceDeviceAddress = tostring(ExtendedProperties.SourceDeviceAddress), 
           DestDeviceAddress = tostring(ExtendedProperties.DestinationDeviceAddress), 
           RemediationSteps = tostring(parse_json(RemediationSteps)[0]), 
           Protocol = tostring(ExtendedProperties.Protocol), 
           AlertManagementUri = tostring(ExtendedProperties.AlertManagementUri)
  | project
    TimeGenerated,
    DeviceId,
    ProductName,
    ProductComponentName,
    AlertSeverity,
    AlertName,
    Description,
    Protocol,
    SourceDeviceAddress,
    DestDeviceAddress,
    RemediationSteps,
    Tactics,
    Entities,
    VendorOriginalId,
    AlertLink,
    AlertManagementUri,
    Techniques
entityMappings:
sentinelEntitiesMappings:
  - columnName: Entities
eventGroupingSettings:
  aggregationKind: AlertPerResult
customDetails:
  Sensor: DeviceId
  Protocol: Protocol
  VendorOriginalId: VendorOriginalId
  AlertManagementUri: AlertManagementUri
alertDetailsOverride:
  alertDisplayNameFormat: (MDIoT) {{AlertName}}
  alertDescriptionFormat: (MDIoT) {{Description}}
  alertTacticsColumnName: Tactics
  alertSeverityColumnName: AlertSeverity
  alertDynamicProperties: 
    - alertProperty: ProductName
      value: ProductName
    - alertProperty: RemediationSteps
      value: RemediationSteps
    - alertProperty: Techniques
      value: Techniques
    - alertProperty: ProductComponentName
      value: ProductComponentName
    - alertProperty: AlertLink
      value: AlertLink
version: 1.0.3
kind: Scheduled

Stages and Predicates

Stage 1: source

SecurityAlert

Stage 2: where

| where ProviderName == "IoTSecurity"

Stage 3: where

| where AlertName == "Unauthorized SSH Access"

Stage 4: extend

| extend ExtendedProperties = parse_json(ExtendedProperties)

Stage 5: where

| where tostring(ExtendedProperties.isNew) == "True"

Stage 6: extend

| extend DeviceId = tostring(ExtendedProperties.DeviceId), 
         SourceDeviceAddress = tostring(ExtendedProperties.SourceDeviceAddress), 
         DestDeviceAddress = tostring(ExtendedProperties.DestinationDeviceAddress), 
         RemediationSteps = tostring(parse_json(RemediationSteps)[0]), 
         Protocol = tostring(ExtendedProperties.Protocol), 
         AlertManagementUri = tostring(ExtendedProperties.AlertManagementUri)

Stage 7: project

| project
  TimeGenerated,
  DeviceId,
  ProductName,
  ProductComponentName,
  AlertSeverity,
  AlertName,
  Description,
  Protocol,
  SourceDeviceAddress,
  DestDeviceAddress,
  RemediationSteps,
  Tactics,
  Entities,
  VendorOriginalId,
  AlertLink,
  AlertManagementUri,
  Techniques

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
AlertNameeq
  • Unauthorized SSH Access transforms: cased
ProviderNameeq
  • IoTSecurity transforms: cased corpus 15 (kusto 15)
isNeweq
  • True transforms: tostring, cased corpus 15 (kusto 15)

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
AlertLinkproject
AlertManagementUriproject
AlertNameproject
AlertSeverityproject
Descriptionproject
DestDeviceAddressproject
DeviceIdproject
Entitiesproject
ProductComponentNameproject
ProductNameproject
Protocolproject
RemediationStepsproject
SourceDeviceAddressproject
Tacticsproject
Techniquesproject
TimeGeneratedproject
VendorOriginalIdproject