# Servers-01 -- Settings Declaration
# Linked to: OU=ExampleServers,DC=example,DC=internal
#
# Server hardening policy. Full audit coverage, PowerShell transcription,
# and operational baselines for domain-joined servers in the ExampleServers OU.
# All settings are Computer Configuration (HKLM).

@{
    GPOName     = 'Servers-01'
    Description = 'Server hardening -- full audit, transcription, and operational baseline'

    DisableUserConfiguration = $true

    LinkTo = 'OU=ExampleServers,DC=example,DC=internal'

    # Defense-in-depth: only apply to member servers (ProductType 3).
    # ProductType 2 = domain controllers (have their own OU/GPO).
    WMIFilter = @{
        Name        = 'Member Servers Only'
        Description = 'Targets member server operating systems (ProductType = 3)'
        Query       = "SELECT * FROM Win32_OperatingSystem WHERE ProductType = 3"
    }

    # Lock down local Administrators to Domain Admins + MasterAdmins only.
    # Any unauthorized additions are removed on next GPO refresh.
    RestrictedGroups = @{
        'BUILTIN\Administrators' = @{
            Members = @('EXAMPLE\Domain Admins', 'EXAMPLE\MasterAdmins')
        }
    }

    SecurityPolicy = @{

        'System Access' = [ordered]@{
            EnableGuestAccount = 0
        }

        'Event Audit' = [ordered]@{
            # Full audit -- servers are high-value targets, log everything
            AuditSystemEvents    = 3    # Success + Failure
            AuditLogonEvents     = 3    # Success + Failure
            AuditObjectAccess    = 3    # Success + Failure
            AuditPrivilegeUse    = 3    # Success + Failure
            AuditPolicyChange    = 3    # Success + Failure
            AuditAccountManage   = 3    # Success + Failure
            AuditProcessTracking = 3    # Success + Failure
            AuditDSAccess        = 3    # Success + Failure
            AuditAccountLogon    = 3    # Success + Failure
        }

        'Registry Values' = [ordered]@{
            # Interactive logon: Machine inactivity limit -- 15 min (servers may have long console sessions)
            'MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\System\InactivityTimeoutSecs' = '4,900'

            # Interactive logon: Don't display last signed-in user
            'MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\System\DontDisplayLastUserName' = '4,1'

            # Interactive logon: Require CTRL+ALT+DEL
            'MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\DisableCAD' = '4,0'
        }
    }

    # =================================================================
    # Windows Firewall -- default-deny inbound, allow management traffic
    # =================================================================

    FirewallProfiles = @{
        Domain  = @{ Enabled = $true; DefaultInboundAction = 'Block'; DefaultOutboundAction = 'Allow' }
        Private = @{ Enabled = $true; DefaultInboundAction = 'Block'; DefaultOutboundAction = 'Allow' }
        Public  = @{ Enabled = $true; DefaultInboundAction = 'Block'; DefaultOutboundAction = 'Allow' }
    }

    FirewallRules = @(
        # WinRM -- remote management (Invoke-Command, Enter-PSSession)
        @{
            DisplayName = 'Allow WinRM HTTP (Inbound)'
            Direction   = 'Inbound'
            Action      = 'Allow'
            Protocol    = 'TCP'
            LocalPort   = '5985'
            Profile     = 'Domain'
            Description = 'Windows Remote Management (HTTP) for domain management'
        }

        # RDP -- remote console access (NLA required via registry setting above)
        @{
            DisplayName = 'Allow RDP (Inbound)'
            Direction   = 'Inbound'
            Action      = 'Allow'
            Protocol    = 'TCP'
            LocalPort   = '3389'
            Profile     = 'Domain'
            Description = 'Remote Desktop Protocol for domain-authenticated sessions'
        }

        # ICMP Echo -- network troubleshooting and monitoring
        @{
            DisplayName = 'Allow ICMP Echo Request (Inbound)'
            Direction   = 'Inbound'
            Action      = 'Allow'
            Protocol    = 'ICMPv4'
            Profile     = 'Domain'
            Description = 'ICMP echo for ping-based health monitoring'
        }

        # SMB -- file sharing and administrative shares (C$, ADMIN$)
        @{
            DisplayName = 'Allow SMB (Inbound)'
            Direction   = 'Inbound'
            Action      = 'Allow'
            Protocol    = 'TCP'
            LocalPort   = '445'
            Profile     = 'Domain'
            Description = 'Server Message Block for file sharing and admin shares'
        }
    )

    # =================================================================
    # GPP Local Groups -- additive membership (does not replace full list)
    # Use RestrictedGroups above for Administrators (exact membership).
    # Use GPP Local Groups here for groups where we add members without
    # wiping existing ones.
    # =================================================================

    Preferences = @{
        LocalUsersAndGroups = @(
            @{
                GroupName      = 'Remote Desktop Users'
                Action         = 'Update'
                DeleteAllUsers  = $false
                DeleteAllGroups = $false
                Members        = @(
                    @{ Name = 'EXAMPLE\MasterAdmins'; Action = 'ADD' }
                )
            }
        )
    }

    # =================================================================
    # Advanced Audit Policy -- granular subcategory-level auditing
    # Overrides the legacy Event Audit above with 53 subcategories.
    # When both are present, Advanced Audit takes precedence on clients.
    # =================================================================

    AdvancedAuditPolicy = @{
        # System
        'Security State Change'              = 'Success and Failure'
        'Security System Extension'          = 'Success and Failure'
        'System Integrity'                   = 'Success and Failure'

        # Logon/Logoff
        'Logon'                              = 'Success and Failure'
        'Logoff'                             = 'Success'
        'Account Lockout'                    = 'Success'
        'Special Logon'                      = 'Success and Failure'
        'Other Logon/Logoff Events'          = 'Success and Failure'
        'Group Membership'                   = 'Success'

        # Object Access
        'File System'                        = 'Success and Failure'
        'Registry'                           = 'Success and Failure'
        'File Share'                         = 'Success and Failure'
        'Detailed File Share'                = 'Failure'
        'SAM'                                = 'Success and Failure'
        'Removable Storage'                  = 'Success and Failure'
        'Filtering Platform Connection'      = 'Failure'

        # Privilege Use
        'Sensitive Privilege Use'            = 'Success and Failure'

        # Detailed Tracking
        'Process Creation'                   = 'Success and Failure'
        'Process Termination'                = 'Success'
        'Plug and Play Events'               = 'Success'

        # Policy Change
        'Audit Policy Change'                = 'Success and Failure'
        'Authentication Policy Change'       = 'Success'
        'MPSSVC Rule-Level Policy Change'    = 'Success and Failure'

        # Account Management
        'User Account Management'            = 'Success and Failure'
        'Computer Account Management'        = 'Success and Failure'
        'Security Group Management'          = 'Success and Failure'
        'Other Account Management Events'    = 'Success and Failure'

        # Account Logon
        'Credential Validation'              = 'Success and Failure'
        'Kerberos Authentication Service'    = 'Success and Failure'
        'Kerberos Service Ticket Operations' = 'Success and Failure'
    }

    RegistrySettings = @(

        # =============================================================
        # Autorun / Autoplay
        # =============================================================

        # Disable autorun on all drive types (bitmask 0xFF = all)
        @{
            Key       = 'HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer'
            ValueName = 'NoDriveTypeAutoRun'
            Type      = 'DWord'
            Value     = 255
        }

        # Disable autoplay entirely
        @{
            Key       = 'HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer'
            ValueName = 'NoAutorun'
            Type      = 'DWord'
            Value     = 1
        }

        # =============================================================
        # Windows Update -- weekly Sunday 3 AM
        # =============================================================

        # Enable automatic updates
        @{
            Key       = 'HKLM\Software\Policies\Microsoft\Windows\WindowsUpdate\AU'
            ValueName = 'NoAutoUpdate'
            Type      = 'DWord'
            Value     = 0
        }

        # Auto download and schedule install
        @{
            Key       = 'HKLM\Software\Policies\Microsoft\Windows\WindowsUpdate\AU'
            ValueName = 'AUOptions'
            Type      = 'DWord'
            Value     = 4
        }

        # Schedule install day (0=Every day, 1=Sunday ... 7=Saturday)
        @{
            Key       = 'HKLM\Software\Policies\Microsoft\Windows\WindowsUpdate\AU'
            ValueName = 'ScheduledInstallDay'
            Type      = 'DWord'
            Value     = 1
        }

        # Schedule install time (0-23, 3 = 3:00 AM)
        @{
            Key       = 'HKLM\Software\Policies\Microsoft\Windows\WindowsUpdate\AU'
            ValueName = 'ScheduledInstallTime'
            Type      = 'DWord'
            Value     = 3
        }

        # =============================================================
        # Logging & Auditing -- full forensic capability
        # =============================================================

        # PowerShell script block logging
        @{
            Key       = 'HKLM\Software\Policies\Microsoft\Windows\PowerShell\ScriptBlockLogging'
            ValueName = 'EnableScriptBlockLogging'
            Type      = 'DWord'
            Value     = 1
        }

        # PowerShell transcription -- full session recording
        @{
            Key       = 'HKLM\Software\Policies\Microsoft\Windows\PowerShell\Transcription'
            ValueName = 'EnableTranscripting'
            Type      = 'DWord'
            Value     = 1
        }

        # Transcription output directory
        @{
            Key       = 'HKLM\Software\Policies\Microsoft\Windows\PowerShell\Transcription'
            ValueName = 'OutputDirectory'
            Type      = 'String'
            Value     = 'C:\PSlogs\Transcripts'
        }

        # Include invocation headers in transcripts (timestamps per command)
        @{
            Key       = 'HKLM\Software\Policies\Microsoft\Windows\PowerShell\Transcription'
            ValueName = 'EnableInvocationHeader'
            Type      = 'DWord'
            Value     = 1
        }

        # PowerShell module logging -- log all module activity
        @{
            Key       = 'HKLM\Software\Policies\Microsoft\Windows\PowerShell\ModuleLogging'
            ValueName = 'EnableModuleLogging'
            Type      = 'DWord'
            Value     = 1
        }

        # Log all modules (wildcard)
        @{
            Key       = 'HKLM\Software\Policies\Microsoft\Windows\PowerShell\ModuleLogging\ModuleNames'
            ValueName = '*'
            Type      = 'String'
            Value     = '*'
        }

        # Command line in process creation events (Event ID 4688)
        @{
            Key       = 'HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System\Audit'
            ValueName = 'ProcessCreationIncludeCmdLine_Enabled'
            Type      = 'DWord'
            Value     = 1
        }

        # Event log sizes -- match AdminWorkstations (servers generate heavy event volume)

        # Application log: 64 MB
        @{
            Key       = 'HKLM\Software\Policies\Microsoft\Windows\EventLog\Application'
            ValueName = 'MaxSize'
            Type      = 'DWord'
            Value     = 65536
        }

        # Security log: 256 MB
        @{
            Key       = 'HKLM\Software\Policies\Microsoft\Windows\EventLog\Security'
            ValueName = 'MaxSize'
            Type      = 'DWord'
            Value     = 262144
        }

        # System log: 64 MB
        @{
            Key       = 'HKLM\Software\Policies\Microsoft\Windows\EventLog\System'
            ValueName = 'MaxSize'
            Type      = 'DWord'
            Value     = 65536
        }

        # PowerShell Operational log: 64 MB
        @{
            Key       = 'HKLM\Software\Policies\Microsoft\Windows\EventLog\Windows PowerShell'
            ValueName = 'MaxSize'
            Type      = 'DWord'
            Value     = 65536
        }

        # =============================================================
        # Remote Desktop
        # =============================================================

        # Require NLA for RDP
        @{
            Key       = 'HKLM\Software\Policies\Microsoft\Windows NT\Terminal Services'
            ValueName = 'UserAuthentication'
            Type      = 'DWord'
            Value     = 1
        }
    )
}