PLC unsecure key state (Microsoft Defender for IoT)

Status: available
Severity: low
Time window: 3h
Source: github.com/Azure/Azure-Sentinel

'This alert leverages Defender for IoT to detect PLC operating mode changes indicating the PLC is potentially insecure. If the PLC is compromised, devices that interact with it may be impacted. This may affect overall system security and safety.'

MITRE ATT&CK coverage

Tactic	Techniques
Execution	`T0858` Change Operating Mode
Evasion	`T0858` Change Operating Mode

Rule body

id: f9df500a-e2a4-4104-a517-dc1d85bb654f
name: PLC unsecure key state (Microsoft Defender for IoT)
description: |
  'This alert leverages Defender for IoT to detect PLC operating mode changes indicating the PLC is potentially insecure. If the PLC is compromised, devices that interact with it may be impacted. This may affect overall system security and safety.'
severity: Low
status: Available
requiredDataConnectors:
  - connectorId: IoT
    dataTypes:
      - SecurityAlert (ASC for IoT)
queryFrequency: 3h
queryPeriod: 3h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - Execution
relevantTechniques:
  - T0858
query: |
  SecurityAlert
  | where ProviderName == "IoTSecurity"
  | where AlertName has "PLC Operating Mode Changed"
  | 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 has "PLC Operating Mode Changed"

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

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`AlertName`	match	`PLC Operating Mode Changed` transforms: `term`	`field:"AlertName" kind:match value:"PLC Operating Mode Changed"`
`ProviderName`	eq	`IoTSecurity`	`field:"ProviderName" kind:eq value:"IoTSecurity"`
`isNew`	eq	`True` transforms: `tostring`	`field:"isNew" kind:eq value:"True"`

Output fields

These fields are emitted when the rule matches.

Field	Source
`AlertLink`	`project`
`AlertManagementUri`	`project`
`AlertName`	`project`
`AlertSeverity`	`project`
`Description`	`project`
`DestDeviceAddress`	`project`
`DeviceId`	`project`
`Entities`	`project`
`ProductComponentName`	`project`
`ProductName`	`project`
`Protocol`	`project`
`RemediationSteps`	`project`
`SourceDeviceAddress`	`project`
`Tactics`	`project`
`Techniques`	`project`
`TimeGenerated`	`project`
`VendorOriginalId`	`project`

PLC unsecure key state (Microsoft Defender for IoT)

MITRE ATT&CK coverage

Rule body

Stages and Predicates

Stage 1: source

Stage 2: where

Stage 3: where

Stage 4: extend

Stage 5: where

Stage 6: extend

Stage 7: project