#requires -Version 3.0 -RunAsAdministrator

<#
   .SYNOPSIS
   Apply the Defender exclusions based on recommendations by Microsoft

   .DESCRIPTION
   Apply the Defender exclusions based on recommendations by Microsoft,
   Some additional Controlled Folder Access Allowed Applications will be added as well

   .EXAMPLE
   PS C:\> Optimize-MicrosoftDefenderExclusions.ps1

   .NOTES
   Do not just use set-mppreference here, this might remove any existing exclusions.
   Might be the right thing to do, but with add-mppreference you append to the list (if exists).

   Changelog:
   1.0.4: Reformated
   1.0.3: Add ControlledFolderAccessAllowedApplications handling
   1.0.2: First real release
   1.0.0: Intital beta version

   Version 1.0.4

   .LINK
   http://enatec.io

   .LINK
   https://support.microsoft.com/en-ie/help/822158/virus-scanning-recommendations-for-enterprise-computers-that-are-runni

   .LINK
   https://docs.microsoft.com/en-us/powershell/module/defender/add-mppreference

   .LINK
   https://docs.microsoft.com/en-us/powershell/module/defender/set-mppreference
#>
[CmdletBinding(ConfirmImpact = 'Medium',
   SupportsShouldProcess)]
param ()

begin
{
   Write-Output -InputObject 'Apply the Defender exclusions based on recommendations by Microsoft'

   #region
   $SCT = 'SilentlyContinue'
   #endregion

   if (Get-Command -Name 'Set-MpPreference' -ErrorAction $SCT)
   {
      $null = (Set-MpPreference -EnableControlledFolderAccess Disabled -Force -ErrorAction $SCT)
   }

   #region DefaultExclusions
   $ExcludePathList = @(
      "$env:windir\SoftwareDistribution\DataStore\Datastore.edb",
      "$env:windir\SoftwareDistribution\DataStore\Logs\Edb*.jrs",
      "$env:windir\SoftwareDistribution\DataStore\Logs\Edb.chk",
      "$env:windir\SoftwareDistribution\DataStore\Logs\Tmp.edb",
      "$env:windir\Security\Database\*.edb",
      "$env:windir\Security\Database\*.sdb",
      "$env:windir\Security\Database\*.log",
      "$env:windir\Security\Database\*.chk",
      "$env:windir\Security\Database\*.jrs",
      "$env:windir\Security\Database\*.xml",
      "$env:windir\Security\Database\*.csv",
      "$env:windir\Security\Database\*.cmtx",
      "$env:windir\System32\GroupPolicy\Machine\Registry.pol",
      "$env:windir\System32\GroupPolicy\Machine\Registry.tmp",
      "$env:windir\System32\GroupPolicy\User\Registry.pol",
      "$env:windir\System32\GroupPolicy\User\Registry.tmp",
      "$env:ProgramData\ntuser.pol",
      "$env:ProgramData\chocolatey\lib\sysinternals\tools\*.exe"
   )
   #endregion DefaultExclusions

   #region AdExclusions
   # Turn off scanning of Active Directory and Active Directory-related files

   # Exclude the Main NTDS database files.
   $DSADatabaseFile = 'HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NTDS\Parameters'
   $DSADatabaseFilePath = ('Registry::' + $DSADatabaseFile)
   $paramTestPath = @{
      Path        = $DSADatabaseFilePath
      ErrorAction = $SCT
   }
   if (Test-Path @paramTestPath)
   {
      $paramGetItemProperty = @{
         Path        = $DSADatabaseFilePath
         ErrorAction = $SCT
      }
      $DSADatabaseFileValue = (Get-ItemProperty @paramGetItemProperty | Select-Object -ExpandProperty 'DSA Database file')

      if ($DSADatabaseFileValue)
      {
         $ExcludePathList += ($DSADatabaseFileValue)
         $ExcludePathList += ($DSADatabaseFileValue).Replace('.dit', '.pat')
      }
   }
   else
   {
      Write-Verbose -Message 'No NTDS database files to exclude'
   }

   # Exclude the Active Directory transaction log files.
   $DatabaseLogFiles = 'HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NTDS\Parameters'
   $DatabaseLogFilesPath = ('Registry::' + $DatabaseLogFiles)

   $paramTestPath = @{
      Path        = $DatabaseLogFilesPath
      ErrorAction = $SCT
   }
   if (Test-Path @paramTestPath)
   {
      $paramGetItemProperty = @{
         Path        = $DatabaseLogFilesPath
         ErrorAction = $SCT
      }
      $DatabaseLogFilesPathValue = (Get-ItemProperty @paramGetItemProperty | Select-Object -ExpandProperty 'Database Log Files Path')

      if ($DatabaseLogFilesPathValue)
      {
         $ExcludePathList += ($DatabaseLogFilesPathValue + '\EDB*.log')
         $ExcludePathList += ($DatabaseLogFilesPathValue + '\Res*.log')
         $ExcludePathList += ($DatabaseLogFilesPathValue + '\Edb*.jrs')
         $ExcludePathList += ($DatabaseLogFilesPathValue + '\Ntds.pat')
      }
   }
   else
   {
      Write-Verbose -Message 'No Active Directory transaction log files to exclude'
   }

   # Exclude the files in the NTDS Working folder
   $DSAWorkingDir = 'HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NTDS\Parameters'
   $DSAWorkingDirPath = ('Registry::' + $DSAWorkingDir)

   $paramTestPath = @{
      Path        = $DSAWorkingDirPath
      ErrorAction = $SCT
   }
   if (Test-Path @paramTestPath)
   {
      $paramGetItemProperty = @{
         Path        = $DSAWorkingDirPath
         ErrorAction = $SCT
      }
      $DSAWorkingDirValue = (Get-ItemProperty @paramGetItemProperty | Select-Object -ExpandProperty 'DSA Working Directory')

      if ($DSAWorkingDirValue)
      {
         $ExcludePathList += ($DSAWorkingDirValue + '\Temp.edb')
         $ExcludePathList += ($DSAWorkingDirValue + '\Edb.chk')
      }
   }
   else
   {
      Write-Verbose -Message 'No NTDS Working folder to exclude'
   }
   #endregion AdExclusions

   #region SysVolExclusions
   # Turn off scanning of SYSVOL files

   # Turn off scanning of files in the File Replication Service (FRS) Working folder
   $SysVolWorkingDir = 'HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NtFrs\Parameters'
   $SysVolWorkingDirPath = ('Registry::' + $SysVolWorkingDir)

   $paramTestPath = @{
      Path        = $SysVolWorkingDirPath
      ErrorAction = $SCT
   }
   if (Test-Path @paramTestPath)
   {
      $paramGetItemProperty = @{
         Path        = $SysVolWorkingDirPath
         ErrorAction = $SCT
      }
      $SysVolWorkingDirValue = (Get-ItemProperty @paramGetItemProperty | Select-Object -ExpandProperty 'Working Directory')
      if ($SysVolWorkingDirValue)
      {
         $ExcludePathList += ($SysVolWorkingDirValue + '\jet\sys\edb.chk')
         $ExcludePathList += ($SysVolWorkingDirValue + '\jet\Ntfrs.jdb')
         $ExcludePathList += ($SysVolWorkingDirValue + '\jet\log\*.log')
      }
   }
   else
   {
      Write-Verbose -Message 'No File Replication Service Working folder to exclude'
   }

   # Turn off scanning of files in the File Replication Service Database Log files
   $SysVolDBLogFileDir = 'HKEY_LOCAL_MACHINE\SYSTEM\Currentcontrolset\Services\Ntfrs\Parameters'
   $SysVolDBLogFileDirPath = ('Registry::' + $SysVolDBLogFileDir)

   if (Test-Path -Path $SysVolDBLogFileDirPath -ErrorAction $SCT)
   {
      $paramGetItemProperty = @{
         Path        = $SysVolWorkingDirPath
         ErrorAction = $SCT
      }
      $SysVolDBLogFileDirValue = (Get-ItemProperty @paramGetItemProperty | Select-Object -ExpandProperty 'Working Directory')

      if ($SysVolDBLogFileDirValue)
      {
         $ExcludePathList += ($SysVolDBLogFileDirValue + '\Jet\Log\Edb*.jrs')
      }
      else
      {
         if ($SysVolWorkingDirValue)
         {
            $ExcludePathList += ($SysVolWorkingDirValue + '\jet\Log\Edb*.log')
         }
      }
   }
   else
   {
      Write-Verbose -Message 'No File Replication Service Database Log files to exclude'
   }
   #endregion SysVolExclusions

   #region DhcpExclusions
   # Turn off scanning of DHCP files
   $DhcpFiles = 'HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\DHCPServer\Parameters'
   $DhcpFilesPath = ('Registry::' + $DhcpFiles)

   $paramTestPath = @{
      Path        = $DhcpFilesPath
      ErrorAction = $SCT
   }
   if (Test-Path @paramTestPath)
   {
      $paramGetItemProperty = @{
         Path        = $DhcpFilesPath
         ErrorAction = $SCT
      }
      $DhcpDatabasePathValue = (Get-ItemProperty @paramGetItemProperty | Select-Object -ExpandProperty 'DatabasePath')
      if ($DhcpDatabasePathValue)
      {
         $ExcludePathList += ($DhcpDatabasePathValue + '\*.mdb')
         $ExcludePathList += ($DhcpDatabasePathValue + '\*.pat')
         $ExcludePathList += ($DhcpDatabasePathValue + '\*.chk')
         $ExcludePathList += ($DhcpDatabasePathValue + '\*.edb')
      }

      $paramGetItemProperty = @{
         Path        = $DhcpFilesPath
         ErrorAction = $SCT
      }
      $DhcpLogFilePathValue = (Get-ItemProperty @paramGetItemProperty | Select-Object -ExpandProperty 'DhcpLogFilePath')

      if (($DhcpLogFilePathValue) -and ($DhcpLogFilePathValue -ne $DhcpDatabasePathValue))
      {
         $ExcludePathList += ($DhcpLogFilePathValue + '\*.log')
      }
      else
      {
         $ExcludePathList += ($DhcpDatabasePathValue + '\*.log')
      }

      $paramGetItemProperty = @{
         Path        = $DhcpFilesPath
         ErrorAction = $SCT
      }

      $DhcpBackupDatabasePathValue = (Get-ItemProperty @paramGetItemProperty | Select-Object -ExpandProperty 'BackupDatabasePath')

      if ($DhcpBackupDatabasePathValue)
      {
         $ExcludePathList += ($DhcpBackupDatabasePathValue + '\new\*.mdb')
         $ExcludePathList += ($DhcpBackupDatabasePathValue + '\new\*.pat')
         $ExcludePathList += ($DhcpBackupDatabasePathValue + '\new\*.chk')
         $ExcludePathList += ($DhcpBackupDatabasePathValue + '\new\*.edb')
         $ExcludePathList += ($DhcpBackupDatabasePathValue + '\new\*.log')
      }
   }
   else
   {
      Write-Verbose -Message 'No DHCP Server Directory found'
   }
   #endregion DhcpExclusions

   #region DnsExclusions
   $DnsServerDir = "$env:windir\System32\dns"

   $paramTestPath = @{
      Path        = $DnsServerDir
      ErrorAction = $SCT
   }
   if (Test-Path @paramTestPath)
   {
      $ExcludePathList += ($DnsServerDir + '\*.log')
      $ExcludePathList += ($DnsServerDir + '\*.dns')
      $ExcludePathList += ($DnsServerDir + '\BOOT')

      $DnsBackupServerDir = ($DnsServerDir + '\backup')

      $paramTestPath = @{
         Path        = $DnsBackupServerDir
         ErrorAction = $SCT
      }
      if (Test-Path @paramTestPath)
      {
         $ExcludePathList += ($DnsBackupServerDir + '\*.log')
         $ExcludePathList += ($DnsBackupServerDir + '\*.dns')
         $ExcludePathList += ($DnsBackupServerDir + '\BOOT')
      }
   }
   else
   {
      Write-Verbose -Message 'No DNS Server Directory found'
   }
   #endregion DnsExclusions

   #region WinsExclusions
   $WinsServerDir = "$env:windir\System32\Wins"

   $paramTestPath = @{
      Path        = $WinsServerDir
      ErrorAction = $SCT
   }
   if (Test-Path @paramTestPath)
   {
      Write-Warning -Message 'WINS is still installed on this system!' -WarningAction Continue

      $ExcludePathList += ($WinsServerDir + '\*.chk')
      $ExcludePathList += ($WinsServerDir + '\*.log')
      $ExcludePathList += ($WinsServerDir + '\*.mdb')
   }
   else
   {
      Write-Verbose -Message 'No WINS Server Directory found'
   }
   #endregion WinsExclusions
}

process
{
   if ($pscmdlet.ShouldProcess($ExcludePathList, 'Exclude from Microsoft Defender Scanning'))
   {
      # Loop over the list we created
      foreach ($ExcludePath in $ExcludePathList)
      {
         try
         {
            # Splat the parameters for Add-MpPreference
            $SplatAddMpPreference = @{
               ExclusionPath = $ExcludePath
               Force         = $true
               ErrorAction   = 'Stop'
               WarningAction = 'Continue'
            }
            $null = (Add-MpPreference @SplatAddMpPreference)
         }
         catch
         {
            #region ErrorHandler
            # get error record
            [Management.Automation.ErrorRecord]$e = $_

            # retrieve information about runtime error
            $info = @{
               Exception = $e.Exception.Message
               Reason    = $e.CategoryInfo.Reason
               Target    = $e.CategoryInfo.TargetName
               Script    = $e.InvocationInfo.ScriptName
               Line      = $e.InvocationInfo.ScriptLineNumber
               Column    = $e.InvocationInfo.OffsetInLine
            }

            # Error Stack
            $info | Out-String | Write-Verbose

            # Just display the info on continue with the rest of the list
            Write-Warning -Message ($info.Exception) -ErrorAction Continue -WarningAction Continue

            # Cleanup
            $info = $null
            $e = $null
            #endregion ErrorHandler
         }
      }
   }

   if ($pscmdlet.ShouldProcess($ExcludePathList, 'Tweak Controlled Folder AccessAllowed Applications'))
   {
      $paramGetMpPreference = @{
         ErrorAction = $SCT
      }
      $CurrentAllowedApplications = ((Get-MpPreference @paramGetMpPreference).ControlledFolderAccessAllowedApplications)

      # Prevent issues with missing allowed applications
      if (-not ($CurrentAllowedApplications))
      {
         # New installations might not have allowed applications, let us create an empty object
         $CurrentAllowedApplications = @()
      }

      $AllowedApplications = @(
         'C:\Program Files (x86)\KeePass Password Safe 2\KeePass.exe'
         'C:\Program Files\Intel\Intel(R) Rapid Storage Technology\IAStorDataMgrSvc.exe'
         'C:\ProgramData\chocolatey\lib\vlc\tools\vlc-*-win64_x64.exe'
         'C:\swsetup\SP*\HPImageAssistant.dll'
         'C:\Users\*\AppData\Local\Programs\Mark Text\Mark Text.exe'
         'C:\Users\*\AppData\Local\Temp\chocolatey\is-*.tmp\WinSCP-*-Setup.tmp'
         'C:\Windows\explorer.exe'
         'C:\Windows\System32\svchost.exe'
         'C:\Windows\System32\WindowsPowerShell\v1.0\powershell_ise.exe'
      )

      $AllowedApplications | ForEach-Object -Process {
         if (-not ($CurrentAllowedApplications.Contains($_)))
         {
            # Not the fasted way, but this will work just fine
            $CurrentAllowedApplications += $_
         }
      }

      try
      {
         # Apply the new (merged) allowed application list to the Defender Controlled Folder Access Allowed feature
         $paramAddMpPreference = @{
            ControlledFolderAccessAllowedApplications = $CurrentAllowedApplications
            Force                                     = $true
            ErrorAction                               = 'Stop'
         }
         $null = (Add-MpPreference @paramAddMpPreference)
      }
      catch
      {
         Write-Warning -Message 'Unable to modify the allow list...'
      }
   }
}

end
{
   if (Get-Command -Name 'Set-MpPreference' -ErrorAction $SCT)
   {
      $null = (Set-MpPreference -EnableControlledFolderAccess Enabled -Force -ErrorAction $SCT)
   }
}

#region LICENSE
<#
BSD 3-Clause License

Copyright (c) 2021, enabling Technology
All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#>
#endregion LICENSE

#region DISCLAIMER
<#
DISCLAIMER:
- Use at your own risk, etc.
- This is open-source software, if you find an issue try to fix it yourself. There is no support and/or warranty in any kind
- This is a third-party Software
- The developer of this Software is NOT sponsored by or affiliated with Microsoft Corp (MSFT) or any of its subsidiaries in any way
- The Software is not supported by Microsoft Corp (MSFT)
- By using the Software, you agree to the License, Terms, and any Conditions declared and described above
- If you disagree with any of the Terms, and any Conditions declared: Just delete it and build your own solution
#>
#endregion DISCLAIMER