functions/Copy-DbaCredential.ps1

function Copy-DbaCredential {
    <#
        .SYNOPSIS
            Copy-DbaCredential migrates SQL Server Credentials from one SQL Server to another while maintaining Credential passwords.
 
        .DESCRIPTION
            By using password decryption techniques provided by Antti Rantasaari (NetSPI, 2014), this script migrates SQL Server Credentials from one server to another while maintaining username and password.
 
            Credit: https://blog.netspi.com/decrypting-mssql-database-link-server-passwords/
            License: BSD 3-Clause http://opensource.org/licenses/BSD-3-Clause
 
        .PARAMETER Source
            Source SQL Server. You must have sysadmin access and server version must be SQL Server version 2000 or higher.
 
        .PARAMETER SourceSqlCredential
            Login to the target instance using alternative credentials. Windows and SQL Authentication supported. Accepts credential objects (Get-Credential)
 
        .PARAMETER Destination
            Destination SQL Server. You must have sysadmin access and the server must be SQL Server 2000 or higher.
 
        .PARAMETER DestinationSqlCredential
            Login to the target instance using alternative credentials. Windows and SQL Authentication supported. Accepts credential objects (Get-Credential)
 
        .PARAMETER Credential
             This command requires access to the Windows OS via PowerShell remoting. Use this credential to connect to Windows using alternative credentials.
 
        .PARAMETER Name
            Only include specific names
            Note: if spaces exist in the credential name, you will have to type "" or '' around it.
 
        .PARAMETER ExcludeName
            Excluded credential names
     
        .PARAMETER Identity
            Only include specific identities
            Note: if spaces exist in the credential identity, you will have to type "" or '' around it.
 
        .PARAMETER ExcludeIdentity
            Excluded identities
 
        .PARAMETER Force
            If this switch is enabled, the Credential will be dropped and recreated if it already exists on Destination.
 
        .PARAMETER WhatIf
            If this switch is enabled, no actions are performed but informational messages will be displayed that explain what would happen if the command were to run.
 
        .PARAMETER Confirm
            If this switch is enabled, you will be prompted for confirmation before executing any operations that change state.
 
        .PARAMETER EnableException
            By default, when something goes wrong we try to catch it, interpret it and give you a friendly warning message.
            This avoids overwhelming you with "sea of red" exceptions, but is inconvenient because it basically disables advanced scripting.
            Using this switch turns this "nice by default" feature off and enables you to catch exceptions with your own try/catch.
 
        .NOTES
            Tags: WSMan, Migration
            Author: Chrissy LeMaire (@cl), netnerds.net
            Requires:
                - PowerShell Version 3.0, SQL Server SMO,
                - Administrator access on Windows
                - sysadmin access on SQL Server.
                - DAC access enabled for local (default)
            Limitations: Hasn't been tested thoroughly. Works on Win8.1 and SQL Server 2012 & 2014 so far.
 
            Website: https://dbatools.io
            Copyright: (C) Chrissy LeMaire, clemaire@gmail.com
            License: MIT https://opensource.org/licenses/MIT
 
        .LINK
            https://dbatools.io/Copy-DbaCredential
 
        .EXAMPLE
            Copy-DbaCredential -Source sqlserver2014a -Destination sqlcluster
 
            Copies all SQL Server Credentials on sqlserver2014a to sqlcluster. If Credentials exist on destination, they will be skipped.
 
        .EXAMPLE
            Copy-DbaCredential -Source sqlserver2014a -Destination sqlcluster -Name "PowerShell Proxy Account" -Force
 
            Copies over one SQL Server Credential (PowerShell Proxy Account) from sqlserver to sqlcluster. If the Credential already exists on the destination, it will be dropped and recreated.
    #>

    [CmdletBinding(SupportsShouldProcess)]
    param (
        [parameter(Mandatory)]
        [DbaInstanceParameter]$Source,
        [PSCredential]
        $SourceSqlCredential,
        [PSCredential]
        $Credential,
        [parameter(Mandatory)]
        [DbaInstanceParameter[]]$Destination,
        [PSCredential]$DestinationSqlCredential,
        [string[]]$Name,
        [string[]]$ExcludeName,
        [Alias('CredentialIdentity')]
        [string[]]$Identity,
        [Alias('ExcludeCredentialIdentity')]
        [string[]]$ExcludeIdentity,
        [switch]$Force,
        [Alias('Silent')]
        [switch]$EnableException
    )

    begin {
        $null = Test-ElevationRequirement -ComputerName $Source.ComputerName

        function Copy-Credential {
            <#
                .SYNOPSIS
                    Copies Credentials from one server to another using a combination of SMO's .Script() and manual password updates.
 
                .OUTPUT
                    System.Data.DataTable
            #>

            param (
                [string[]]$Credentials,
                [bool]$Force
            )

            Write-Message -Level Verbose -Message "Collecting Credential logins and passwords on $($sourceServer.Name)"
            $sourceCredentials = Get-DecryptedObject -SqlInstance $sourceServer -Type Credential
            $credentialList = Get-DbaCredential -SqlInstance $sourceServer -Name $Name -ExcludeName $ExcludeName -Identity $Identity -ExcludeIdentity $ExcludeIdentity
            
            Write-Message -Level Verbose -Message "Starting migration"
            foreach ($credential in $credentialList) {
                $destServer.Credentials.Refresh()
                $credentialName = $credential.Name

                $copyCredentialStatus = [pscustomobject]@{
                    SourceServer      = $sourceServer.Name
                    DestinationServer = $destServer.Name
                    Type              = "Credential"
                    Name              = $credentialName
                    Status            = $null
                    Notes             = $null
                    DateTime          = [DbaDateTime](Get-Date)
                }

                if ($null -ne $destServer.Credentials[$credentialName]) {
                    if (!$force) {
                        $copyCredentialStatus.Status = "Skipping"
                        $copyCredentialStatus.Notes = "Already exists"
                        $copyCredentialStatus | Select-DefaultView -Property DateTime, SourceServer, DestinationServer, Name, Type, Status, Notes -TypeName MigrationObject

                        Write-Message -Level Verbose -Message "$credentialName exists $($destServer.Name). Skipping."
                        continue
                    }
                    else {
                        if ($Pscmdlet.ShouldProcess($destinstance.Name, "Dropping $identity")) {
                            $destServer.Credentials[$credentialName].Drop()
                            $destServer.Credentials.Refresh()
                        }
                    }
                }
                
                Write-Message -Level Verbose -Message "Attempting to migrate $credentialName"
                try {
                    $currentCred = $sourceCredentials | Where-Object { $_.Name -eq "[$credentialName]" }
                    $sqlcredentialName = $credentialName.Replace("'", "''")
                    $identity = $currentCred.Identity.Replace("'", "''")
                    $password = $currentCred.Password.Replace("'","''")
                    if ($Pscmdlet.ShouldProcess($destinstance.Name, "Copying $identity")) {
                        $destServer.Query("CREATE CREDENTIAL [$sqlcredentialName] WITH IDENTITY = N'$identity', SECRET = N'$password'")
                        $destServer.Credentials.Refresh()
                        Write-Message -Level Verbose -Message "$credentialName successfully copied"
                    }

                    $copyCredentialStatus.Status = "Successful"
                    $copyCredentialStatus | Select-DefaultView -Property DateTime, SourceServer, DestinationServer, Name, Type, Status, Notes -TypeName MigrationObject
                }
                catch {
                    $copyCredentialStatus.Status = "Failed"
                    $copyCredentialStatus | Select-DefaultView -Property DateTime, SourceServer, DestinationServer, Name, Type, Status, Notes -TypeName MigrationObject

                    Stop-Function -Message "Error creating credential" -Target $credentialName -ErrorRecord $_
                }
            }
        }
        
        try {
            Write-Message -Level Verbose -Message "Connecting to $Source"
            $sourceServer = Connect-SqlInstance -SqlInstance $Source -SqlCredential $SourceSqlCredential -MinimumVersion 9
        }
        catch {
            Stop-Function -Message "Failure" -Category ConnectionError -ErrorRecord $_ -Target $instance
            return
        }
        
        if ($null -ne $SourceSqlCredential.Username) {
            Write-Message -Level Verbose -Message "You are using SQL credentials and this script requires Windows admin access to the $Source server. Trying anyway."
        }
        
        $sourceNetBios = Resolve-NetBiosName $sourceServer
        
        Invoke-SmoCheck -SqlInstance $sourceServer
        
        Write-Message -Level Verbose -Message "Checking if Remote Registry is enabled on $source"
        try {
            Invoke-Command2 -ComputerName $sourceNetBios -Credential $credential -ScriptBlock { Get-ItemProperty -Path "HKLM:\SOFTWARE\" }
        }
        catch {
            Stop-Function -Message "Can't connect to registry on $source" -Target $sourceNetBios -ErrorRecord $_
            return
        }
    }
    process {
        if (Test-FunctionInterrupt) { return }
        
        foreach ($destinstance in $Destination) {
            try {
                Write-Message -Level Verbose -Message "Connecting to $destinstance"
                $destServer = Connect-SqlInstance -SqlInstance $destinstance -SqlCredential $DestinationSqlCredential -MinimumVersion 9
            }
            catch {
                Stop-Function -Message "Failure" -Category ConnectionError -ErrorRecord $_ -Target $destinstance -Continue
            }
            Invoke-SmoCheck -SqlInstance $destServer
            
            Copy-Credential $credentials -force:$force
        }
    }
    end {
        Test-DbaDeprecation -DeprecatedOn "1.0.0" -EnableException:$false -Alias Copy-SqlCredential
    }
}