Security Service Registry ACL Modification

id: 473d57e6-f787-435c-a16b-b38b51fa9a4b
name: Security Service Registry ACL Modification
description: |
    'Identifies attempts to modify registry ACL to evade security solutions. In the Solorigate attack, the attackers were found modifying registry permissions so services.exe cannot access the relevant registry keys to start the service.
     The detection leverages Security Event as well as MDE data to identify when specific security services registry permissions are modified.
     Only some portions of this detection are related to Solorigate, it also includes coverage for some common tools that perform this activity.
     Reference on guidance for enabling registry auditing:
     - https://docs.microsoft.com/windows/security/threat-protection/auditing/advanced-security-auditing-faq
     - https://docs.microsoft.com/windows/security/threat-protection/auditing/appendix-a-security-monitoring-recommendations-for-many-audit-events
     - https://docs.microsoft.com/windows/security/threat-protection/auditing/audit-registry
     - https://docs.microsoft.com/windows/security/threat-protection/auditing/event-4670
       - For the event 4670 to be created the audit policy for the registry must have auditing enabled for Write DAC and/or Write Owner
     - https://github.com/OTRF/Set-AuditRule
     - https://docs.microsoft.com/dotnet/api/system.security.accesscontrol.registryrights?view=dotnet-plat-ext-5.0'
severity: High
requiredDataConnectors:
  - connectorId: SecurityEvents
    dataTypes:
      - SecurityEvent
  - connectorId: MicrosoftThreatProtection
    dataTypes:
      - DeviceProcessEvents
  - connectorId: WindowsSecurityEvents
    dataTypes:
      - SecurityEvents
  - connectorId: WindowsForwardedEvents
    dataTypes:
      - WindowsEvent
queryFrequency: 1d
queryPeriod: 1d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - DefenseEvasion
relevantTechniques:
  - T1562
tags:
  - Solorigate
  - NOBELIUM
query: |
  let servicelist = dynamic(['Services\\HealthService', 'Services\\Sense', 'Services\\WinDefend', 'Services\\MsSecFlt', 'Services\\DiagTrack', 'Services\\SgrmBroker', 'Services\\SgrmAgent', 'Services\\AATPSensorUpdater' , 'Services\\AATPSensor', 'Services\\mpssvc']);
  let filename = dynamic(["subinacl.exe",'SetACL.exe']);
  let parameters = dynamic (['/deny=SYSTEM', '/deny=S-1-5-18', '/grant=SYSTEM=r', '/grant=S-1-5-18=r', 'n:SYSTEM;p:READ', 'n1:SYSTEM;ta:remtrst;w:dacl']);
  let FullAccess = dynamic(['A;CI;KA;;;SY', 'A;ID;KA;;;SY', 'A;CIID;KA;;;SY']);
  let ReadAccess = dynamic(['A;CI;KR;;;SY', 'A;ID;KR;;;SY', 'A;CIID;KR;;;SY']);
  let DenyAccess = dynamic(['D;CI;KR;;;SY', 'D;ID;KR;;;SY', 'D;CIID;KR;;;SY']);
  let timeframe = 1d;
  (union isfuzzy=true
  (
  SecurityEvent
  | where TimeGenerated >= ago(timeframe)
  | where EventID == 4670
  | where ObjectType == 'Key'
  | where ObjectName has_any (servicelist)
  | parse EventData with * 'OldSd">' OldSd "<" *
  | parse EventData with * 'NewSd">' NewSd "<" *
  | extend Reason = case( (OldSd has ';;;SY' and NewSd !has ';;;SY'), 'System Account is removed', (OldSd has_any (FullAccess) and NewSd has_any (ReadAccess)) , 'System permission has been changed to read from full access', (OldSd has_any (FullAccess) and NewSd has_any (DenyAccess)), 'System account has been given denied permission', 'None')
  | project TimeGenerated, Computer, Account,  ProcessName, ProcessId, ObjectName, EventData, Activity, HandleId, SubjectLogonId, OldSd, NewSd , Reason
  ),
  (
  SecurityEvent
  | where TimeGenerated >= ago(timeframe)
  | where EventID == 4688
  | extend ProcessName = tostring(split(NewProcessName, '\\')[-1])
  | where ProcessName in~ (filename)
  | where CommandLine has_any (servicelist) and CommandLine has_any (parameters)
  | project TimeGenerated, Computer, Account, AccountDomain, ProcessName, ProcessNameFullPath = NewProcessName, EventID, Activity, CommandLine, EventSourceName, Type
  ),
  (
  WindowsEvent
  | where TimeGenerated >= ago(timeframe)
  | where EventID == 4670 and EventData has_any (servicelist) and EventData has 'Key'
  | extend ObjectType = tostring(EventData.ObjectType)
  | where ObjectType == 'Key'
  | extend ObjectName = tostring(EventData.ObjectName)
  | where ObjectName has_any (servicelist)
  | extend OldSd = tostring(EventData.OldSd)
  | extend NewSd = tostring(EventData.NewSd)
  | extend Reason = case( (OldSd has ';;;SY' and NewSd !has ';;;SY'), 'System Account is removed', (OldSd has_any (FullAccess) and NewSd has_any (ReadAccess)) , 'System permission has been changed to read from full access', (OldSd has_any (FullAccess) and NewSd has_any (DenyAccess)), 'System account has been given denied permission', 'None')
  | extend Account =  strcat(tostring(EventData.SubjectDomainName),"\\", tostring(EventData.SubjectUserName))
  | extend ProcessName = tostring(EventData.ProcessName)
  | extend ProcessId = tostring(EventData.ProcessId)
  | extend Activity= "4670 - Permissions on an object were changed."
  | extend HandleId = tostring(EventData.HandleId)
  | extend  SubjectLogonId = tostring(EventData.SubjectLogonId)
  | project TimeGenerated, Computer, Account,  ProcessName, ProcessId, ObjectName, EventData, Activity, HandleId, SubjectLogonId, OldSd, NewSd , Reason
  ),
  (
  WindowsEvent
  | where TimeGenerated >= ago(timeframe)
  | where EventID == 4688 and EventData has_any (filename) and EventData has_any (servicelist) and EventData has_any (parameters)
  | extend NewProcessName = tostring(EventData.NewProcessName)
  | extend ProcessName = tostring(split(NewProcessName, '\\')[-1])
  | where ProcessName in~ (filename)
  | extend CommandLine = tostring(EventData.CommandLine)
  | where CommandLine has_any (servicelist) and CommandLine has_any (parameters)
  | extend  Account =  strcat(tostring(EventData.SubjectDomainName),"\\", tostring(EventData.SubjectUserName))
  | extend  AccountDomain = tostring(EventData.AccountDomain)
  | extend  Activity="4688 - A new process has been created."
  | extend  EventSourceName=Provider
  | project TimeGenerated, Computer, Account, AccountDomain, ProcessName, ProcessNameFullPath = NewProcessName, EventID, Activity, CommandLine, EventSourceName, Type
  ),
  (
  DeviceProcessEvents
  | where TimeGenerated >= ago(timeframe)
  | where InitiatingProcessFileName in~ (filename)
  | where InitiatingProcessCommandLine has_any(servicelist) and InitiatingProcessCommandLine has_any (parameters)
  | extend Account = iff(isnotempty(InitiatingProcessAccountUpn), InitiatingProcessAccountUpn, InitiatingProcessAccountName), Computer = DeviceName
  | project TimeGenerated, Computer, Account, AccountDomain, ProcessName = InitiatingProcessFileName, ProcessNameFullPath = FolderPath, Activity = ActionType, CommandLine = InitiatingProcessCommandLine, Type, InitiatingProcessParentFileName
  )
  )
  | extend AccountName = tostring(split(Account, "\\")[0]), AccountNTDomain = tostring(split(Account, "\\")[1])
  | extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
  | extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: Account
      - identifier: Name
        columnName: AccountName
      - identifier: NTDomain
        columnName: AccountNTDomain
  - entityType: Host
    fieldMappings:
      - identifier: FullName
        columnName: Computer
      - identifier: HostName
        columnName: HostName
      - identifier: NTDomain
        columnName: HostNameDomain
version: 1.1.4
kind: Scheduled
metadata:
    source:
        kind: Community
    author:
        name: Microsoft Security Research
    support:
        tier: Community
    categories:
        domains: [ "Security - Others" ]