Detect Print Processors Registry Driver Key CreationModification

// Print Processor Registry Key RegEx
let printProcessorRegistryRegEx = @'HKEY_LOCAL_MACHINE\\SYSTEM\\[A-Za-z0-9]*ControlSet[A-Za-z0-9]*\\Control\\Print\\Environments\\Windows\s[A-Za-z0-9]+\\Print Processors\\[A-Za-z0-9]+\\Driver';
_ASim_RegistryEvent
| where EventType in ('RegistryValueSet', 'RegistryKeyCreated')
| where RegistryKey matches regex printProcessorRegistryRegEx
| project
    TimeGenerated,
    DvcHostname,
    ActorUsername,
    ActorUsernameType,
    ActingProcessId,
    ActingProcessName,
    ActingProcessCommandLine,
    RegistryKey,
    RegistryValue,
    RegistryValueType,
    RegistryValueData
| extend HostName = tostring(split(DvcHostname, '.')[0])
| extend DnsDomain = tostring(strcat_array(array_slice(split(DvcHostname, '.'), 1, -1), '.'))
| extend Username = iff(tostring(ActorUsernameType) == 'Windows', tostring(split(ActorUsername, '\\')[1]), ActorUsername)
| extend NTDomain = iff(tostring(ActorUsernameType) == 'Windows', tostring(split(ActorUsername, '\\')[0]), ActorUsername)
| extend Username = iff(tostring(ActorUsernameType) == 'UPN', tostring(split(ActorUsername, '@')[0]), Username)
| extend UPNSuffix = iff(tostring(ActorUsernameType) == 'UPN', tostring(split(ActorUsername, '@')[1]), '')
| extend RegHive = tostring(split(RegistryKey, '\\')[0]), RegKey = tostring(strcat_array(array_slice(split(RegistryKey, '\\'), 1, -1), '\\')) 

queryFrequency: 1h
description: |
    This analytic rule detects any registry value creation or modification of print processor registry Driver key. This will load the executable at startup with print spooler service. This could be an indication of a persistence attempt by an adversary.
query: |
  // Print Processor Registry Key RegEx
  let printProcessorRegistryRegEx = @'HKEY_LOCAL_MACHINE\\SYSTEM\\[A-Za-z0-9]*ControlSet[A-Za-z0-9]*\\Control\\Print\\Environments\\Windows\s[A-Za-z0-9]+\\Print Processors\\[A-Za-z0-9]+\\Driver';
  _ASim_RegistryEvent
  | where EventType in ('RegistryValueSet', 'RegistryKeyCreated')
  | where RegistryKey matches regex printProcessorRegistryRegEx
  | project
      TimeGenerated,
      DvcHostname,
      ActorUsername,
      ActorUsernameType,
      ActingProcessId,
      ActingProcessName,
      ActingProcessCommandLine,
      RegistryKey,
      RegistryValue,
      RegistryValueType,
      RegistryValueData
  | extend HostName = tostring(split(DvcHostname, '.')[0])
  | extend DnsDomain = tostring(strcat_array(array_slice(split(DvcHostname, '.'), 1, -1), '.'))
  | extend Username = iff(tostring(ActorUsernameType) == 'Windows', tostring(split(ActorUsername, '\\')[1]), ActorUsername)
  | extend NTDomain = iff(tostring(ActorUsernameType) == 'Windows', tostring(split(ActorUsername, '\\')[0]), ActorUsername)
  | extend Username = iff(tostring(ActorUsernameType) == 'UPN', tostring(split(ActorUsername, '@')[0]), Username)
  | extend UPNSuffix = iff(tostring(ActorUsernameType) == 'UPN', tostring(split(ActorUsername, '@')[1]), '')
  | extend RegHive = tostring(split(RegistryKey, '\\')[0]), RegKey = tostring(strcat_array(array_slice(split(RegistryKey, '\\'), 1, -1), '\\'))   
status: Available
triggerOperator: gt
queryPeriod: 1h
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Malware Protection Essentials/Analytic Rules/PrintProcessersModified.yaml
relevantTechniques:
- T1547
eventGroupingSettings:
  aggregationKind: SingleAlert
tactics:
- Persistence
- PrivilegeEscalation
kind: Scheduled
name: Detect Print Processors Registry Driver Key Creation/Modification
requiredDataConnectors:
- connectorId: CrowdStrikeFalconEndpointProtection
  dataTypes:
  - CommonSecurityLog
- connectorId: MicrosoftThreatProtection
  dataTypes:
  - SecurityAlert
- connectorId: SentinelOne
  dataTypes:
  - SentinelOne_CL
- connectorId: VMwareCarbonBlack
  dataTypes:
  - CarbonBlackEvents_CL
- connectorId: CiscoSecureEndpoint
  dataTypes:
  - CiscoSecureEndpoint_CL
- connectorId: TrendMicroApexOne
  dataTypes:
  - TMApexOneEvent
- connectorId: TrendMicroApexOneAma
  dataTypes:
  - TMApexOneEvent
triggerThreshold: 0
entityMappings:
- entityType: Host
  fieldMappings:
  - columnName: HostName
    identifier: HostName
  - columnName: DnsDomain
    identifier: DnsDomain
  - columnName: NTDomain
    identifier: NTDomain
- entityType: Account
  fieldMappings:
  - columnName: Username
    identifier: Name
  - columnName: UPNSuffix
    identifier: UPNSuffix
  - columnName: NTDomain
    identifier: NTDomain
- entityType: Process
  fieldMappings:
  - columnName: ActingProcessId
    identifier: ProcessId
  - columnName: ActingProcessCommandLine
    identifier: CommandLine
- entityType: RegistryKey
  fieldMappings:
  - columnName: RegHive
    identifier: Hive
  - columnName: RegKey
    identifier: Key
- entityType: RegistryValue
  fieldMappings:
  - columnName: RegistryValue
    identifier: Name
  - columnName: RegistryValueData
    identifier: Value
  - columnName: RegistryValueType
    identifier: ValueType
tags:
- SchemaVersion: 0.1.2
  Schema: _ASim_RegistryEvent
version: 1.0.0
id: 7edde3d4-9859-4a00-b93c-b19ddda55320
alertDetailsOverride:
  alertDisplayNameFormat: Print Processor Registry Driver Keys Modified on {{DvcHostname}} ({{DvcIpAddr}}) by ({{ActorUsername}})
  alertDescriptionFormat: 'Process {{ActingProcessName}} ProcessId: ({{ActingProcessId}}) modified registry driver key {{RegistryKey}}.'
severity: Medium