Detect Print Processors Registry Driver Key Creation/Modification

id: 7edde3d4-9859-4a00-b93c-b19ddda55320
name: Detect Print Processors Registry Driver Key Creation/Modification
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.
severity: Medium
status: Available 
tags:
  - Schema: _ASim_RegistryEvent
    SchemaVersion: 0.1.2
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
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - Persistence
  - PrivilegeEscalation
relevantTechniques:
  - T1547
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), '\\')) 
entityMappings:
  - entityType: Host
    fieldMappings:
      - identifier: HostName
        columnName: HostName
      - identifier: DnsDomain
        columnName: DnsDomain
      - identifier: NTDomain
        columnName: NTDomain
  - entityType: Account
    fieldMappings:
      - identifier: Name
        columnName: Username
      - identifier: UPNSuffix
        columnName: UPNSuffix
      - identifier: NTDomain
        columnName: NTDomain
  - entityType: Process
    fieldMappings:
      - identifier: ProcessId
        columnName: ActingProcessId
      - identifier: CommandLine
        columnName: ActingProcessCommandLine
  - entityType: RegistryKey
    fieldMappings:
      - identifier: Hive
        columnName: RegHive
      - identifier: Key
        columnName: RegKey
  - entityType: RegistryValue
    fieldMappings:
      - identifier: Name
        columnName: RegistryValue
      - identifier: Value
        columnName: RegistryValueData
      - identifier: ValueType
        columnName: RegistryValueType
eventGroupingSettings:
  aggregationKind: SingleAlert
alertDetailsOverride:
  alertDisplayNameFormat: "Print Processor Registry Driver Keys Modified on {{DvcHostname}} ({{DvcIpAddr}}) by ({{ActorUsername}})"
  alertDescriptionFormat: "Process {{ActingProcessName}} ProcessId: ({{ActingProcessId}}) modified registry driver key {{RegistryKey}}."
version: 1.0.0
kind: Scheduled