functions/Copy-SqlCredential.ps1

Function Copy-SqlCredential
{
<#
.SYNOPSIS
Copy-SqlCredential 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

THIS CODE IS PROVIDED "AS IS", WITH NO WARRANTIES.

.PARAMETER Source
Source SQL Server (2005 and above). You must have sysadmin access to both SQL Server and Windows.

.PARAMETER Destination
Destination SQL Server (2005 and above). You must have sysadmin access to both SQL Server and Windows.

.PARAMETER Credentials
Auto-populated list of Credentials from Source. If no Credential is specified, all Credentials will be migrated.
Note: if spaces exist in the credential name, you will have to type "" or '' around it. I couldn't figure out a way around this.

.PARAMETER SourceSqlCredential
Allows you to login to servers using SQL Logins as opposed to Windows Auth/Integrated/Trusted. To use:

$scred = Get-Credential, then pass $scred object to the -SourceSqlCredential parameter.

Windows Authentication will be used if DestinationSqlCredential is not specified. SQL Server does not accept Windows credentials being passed as credentials.
To connect as a different Windows user, run PowerShell as that user.

.PARAMETER DestinationSqlCredential
Allows you to login to servers using SQL Logins as opposed to Windows Auth/Integrated/Trusted. To use:

$dcred = Get-Credential, then pass this $dcred to the -DestinationSqlCredential parameter.

Windows Authentication will be used if DestinationSqlCredential is not specified. SQL Server does not accept Windows credentials being passed as credentials.
To connect as a different Windows user, run PowerShell as that user.

.PARAMETER Force
By default, if a Credential exists on the source and destination, the Credential is not copied over. Specifying -force will drop and recreate the Credential on the Destination server.


.NOTES
Author: Chrissy LeMaire (@cl), netnerds.net
Requires: PowerShell Version 3.0, SQL Server SMO,
            Sys Admin access on Windows and 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.

dbatools PowerShell module (https://dbatools.io, clemaire@gmail.com)
Copyright (C) 2016 Chrissy LeMaire

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.

.LINK
https://dbatools.io/Copy-SqlCredential

.EXAMPLE
Copy-SqlCredential -Source sqlserver2014a -Destination sqlcluster

Description
Copies all SQL Server Credentials on sqlserver2014a to sqlcluster. If credentials exist on destination, they will be skipped.

.EXAMPLE
Copy-SqlCredential -Source sqlserver2014a -Destination sqlcluster -Credentials "PowerShell Proxy Account" -Force

Description
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 = $true)]
    Param (
        [parameter(Mandatory = $true)]
        [object]$Source,
        [parameter(Mandatory = $true)]
        [object]$Destination,
        [System.Management.Automation.PSCredential]$SourceSqlCredential,
        [System.Management.Automation.PSCredential]$DestinationSqlCredential,
        [switch]$Force
        
    )
    
    DynamicParam { if ($source) { return (Get-ParamSqlCredentials -SqlServer $Source -SqlCredential $SourceSqlCredential) } }
    
    BEGIN
    {
        
        Function Get-SqlCredentials
        {
    <#
        .SYNOPSIS
        Gets Credential Logins
         
        This function is heavily based on Antti Rantasaari's script at http://goo.gl/omEOrW
        Antti Rantasaari 2014, NetSPI
        License: BSD 3-Clause http://opensource.org/licenses/BSD-3-Clause
        
        .OUTPUT
        System.Data.DataTable
    
    #>

            [CmdletBinding(DefaultParameterSetName = "Default", SupportsShouldProcess = $true)]
            param (
                [object]$SqlServer,
                [System.Management.Automation.PSCredential]$SqlCredential
            )
            
            $server = Connect-SqlServer -SqlServer $SqlServer -SqlCredential $SqlCredential
            $sourcename = $server.name
            
            # Query Service Master Key from the database - remove padding from the key
            # key_id 102 eq service master key, thumbprint 3 means encrypted with machinekey
            $sql = "SELECT substring(crypt_property,9,len(crypt_property)-8) FROM sys.key_encryptions WHERE key_id=102 and (thumbprint=0x03 or thumbprint=0x0300000001)"
            try { $smkbytes = $server.ConnectionContext.ExecuteScalar($sql) }
            catch { throw "Can't execute SQL on $sourcename" }
            
            $sourcenetbios = Get-NetBiosName $server
            $instance = $server.InstanceName
            $serviceInstanceId = $server.serviceInstanceId
            
            # Get entropy from the registry - hopefully finds the right SQL server instance
            try
            {
                [byte[]]$entropy = Invoke-Command -ComputerName $sourcenetbios -argumentlist $serviceInstanceId {
                    $serviceInstanceId = $args[0]
                    $entropy = (Get-ItemProperty -Path "HKLM:\SOFTWARE\Microsoft\Microsoft SQL Server\$serviceInstanceId\Security\").Entropy
                    return $entropy
                }
            }
            catch { throw "Can't access registry keys on $sourcename. Quitting." }
            
            # Decrypt the service master key
            try
            {
                $servicekey = Invoke-Command -ComputerName $sourcenetbios -argumentlist $smkbytes, $Entropy {
                    Add-Type -assembly System.Security
                    Add-Type -assembly System.Core
                    $smkbytes = $args[0]; $Entropy = $args[1]
                    $servicekey = [System.Security.Cryptography.ProtectedData]::Unprotect($smkbytes, $Entropy, 'LocalMachine')
                    return $servicekey
                }
            }
            catch { throw "Can't unprotect registry data on $($source.name)). Quitting." }
            
            # Choose the encryption algorithm based on the SMK length - 3DES for 2008, AES for 2012
            # Choose IV length based on the algorithm
            if (($servicekey.Length -ne 16) -and ($servicekey.Length -ne 32))
            {
                throw "Unknown key size. Cannot continue. Quitting."
            }
            
            if ($servicekey.Length -eq 16)
            {
                $decryptor = New-Object System.Security.Cryptography.TripleDESCryptoServiceProvider
                $ivlen = 8
            }
            elseif ($servicekey.Length -eq 32)
            {
                $decryptor = New-Object System.Security.Cryptography.AESCryptoServiceProvider
                $ivlen = 16
            }
            
            # Query link server password information from the Db. Remove header from pwdhash, extract IV (as iv) and ciphertext (as pass)
            # Ignore links with blank credentials (integrated auth ?)
            
            if ($server.IsClustered -eq $false) { $connstring = "Server=ADMIN:$sourcenetbios\$instance;Trusted_Connection=True" }
            else { $connstring = "Server=ADMIN:$sourcename;Trusted_Connection=True" }
            
            $sql = "SELECT name,credential_identity,substring(imageval,5,$ivlen) iv, substring(imageval,$($ivlen + 5),len(imageval)-$($ivlen + 4)) pass from sys.credentials cred inner join sys.sysobjvalues obj on cred.credential_id = obj.objid where valclass=28 and valnum=2"
            
            # Get entropy from the registry
            try
            {
                $creds = Invoke-Command -ComputerName $sourcenetbios -argumentlist $connstring, $sql {
                    $connstring = $args[0]; $sql = $args[1]
                    $conn = New-Object System.Data.SqlClient.SQLConnection($connstring)
                    try
                    {
                        $conn.open()
                        $cmd = New-Object System.Data.SqlClient.SqlCommand($sql, $conn);
                        $data = $cmd.ExecuteReader()
                        $dt = New-Object "System.Data.DataTable"
                        $dt.Load($data)
                        $conn.Close()
                        $conn.Dispose()
                        return $dt
                    }
                    catch { throw "Can't open DAC connection :(" }
                }
            }
            catch { throw "Can't establish DAC connection to $sourcename from $sourcename. Quitting." }
            
            $decryptedlogins = New-Object "System.Data.DataTable"
            [void]$decryptedlogins.Columns.Add("Credential")
            [void]$decryptedlogins.Columns.Add("Identity")
            [void]$decryptedlogins.Columns.Add("Password")
            
            # Go through each row in results
            foreach ($cred in $creds)
            {
                # decrypt the password using the service master key and the extracted IV
                $decryptor.Padding = "None"
                $decrypt = $decryptor.Createdecryptor($servicekey, $cred.iv)
                $stream = New-Object System.IO.MemoryStream ( ,$cred.pass)
                $crypto = New-Object System.Security.Cryptography.CryptoStream $stream, $decrypt, "Write"
                
                $crypto.Write($cred.pass, 0, $cred.pass.Length)
                [byte[]]$decrypted = $stream.ToArray()
                
                # convert decrypted password to unicode
                $encode = New-Object System.Text.UnicodeEncoding
                
                # Print results - removing the weird padding (8 bytes in the front, some bytes at the end)...
                # Might cause problems but so far seems to work.. may be dependant on SQL server version...
                # If problems arise remove the next three lines..
                $i = 8; foreach ($b in $decrypted) { if ($decrypted[$i] -ne 0 -and $decrypted[$i + 1] -ne 0 -or $i -eq $decrypted.Length) { $i -= 1; break; }; $i += 1; }
                $decrypted = $decrypted[8..$i]
                
                [void]$decryptedlogins.Rows.Add($($cred.name), $($cred.credential_identity), $($encode.GetString($decrypted)))
            }
            return $decryptedlogins
        }
        
        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 (
                [object]$source,
                [object]$destination,
                [System.Management.Automation.PSCredential]$SourceSqlCredential,
                [System.Management.Automation.PSCredential]$DestinationSqlCredential,
                [string[]]$credentials,
                [bool]$force
            )
            
            Write-Output "Collecting Credential logins and passwords on $($sourceserver.name)"
            $sourcecredentials = Get-SqlCredentials $sourceserver
            
            if ($credentials -ne $null)
            {
                $credentiallist = $sourceserver.credentials | Where-Object { $credentials -contains $_.Name }
            }
            else 
            { 
                $credentiallist = $sourceserver.credentials 
            }
            
            
            Write-Output "Starting migration"
            foreach ($credential in $credentiallist)
            {
                $destserver.credentials.Refresh()
                $credentialname = $credential.name
                
                if ($destserver.credentials[$credentialname] -ne $null)
                {
                    if (!$force)
                    {
                        Write-Warning "$credentialname exists $($destserver.name). Skipping."
                        continue
                    }
                    else
                    {
                        If ($Pscmdlet.ShouldProcess($destination.name, "Dropping $identity"))
                        {
                            $destserver.credentials[$credentialname].Drop()
                            $destserver.credentials.refresh()
                        }
                    }
                }
                
                Write-Output "Attempting to migrate $credentialname"
                
                try
                {
                    $currentcred = $sourcecredentials | Where-Object { $_.Credential -eq $credentialname }
                    $identity = $currentcred.Identity
                    $password = $currentcred.Password
                    
                    If ($Pscmdlet.ShouldProcess($destination.name, "Copying $identity"))
                    {
                        $sql = "CREATE CREDENTIAL [$credentialname] WITH IDENTITY = N'$identity', SECRET = N'$password'"
                        Write-Verbose $sql
                        $destserver.ConnectionContext.ExecuteNonQuery($sql) | Out-Null
                        $destserver.Credentials.Refresh()
                        Write-Output "$credentialname successfully copied"
                    }
                }
                catch 
                { 
                    Write-Exception $_ 
                }
            }
        }
        
        $credentials = $psboundparameters.credentials
        
        if ($SourceSqlCredential.username -ne $null -or $DestinationSqlCredential.username -ne $null)
        {
            Write-Warning "You are using SQL credentials and this script requires Windows admin access to the server. Trying anyway."
        }
        
        $sourceserver = Connect-SqlServer -SqlServer $Source -SqlCredential $SourceSqlCredential
        $destserver = Connect-SqlServer -SqlServer $Destination -SqlCredential $DestinationSqlCredential
        
        $source = $sourceserver.DomainInstanceName
        $destination = $destserver.DomainInstanceName
        
        if ($sourceserver.versionMajor -lt 9 -or $destserver.versionMajor -lt 9)
        {
            throw "Credentials are only supported in SQL Server 2005 and above. Quitting."
        }
        
        Invoke-SmoCheck -SqlServer $sourceserver
        Invoke-SmoCheck -SqlServer $destserver
        
    }
    
    PROCESS
    {
        
        
        Write-Output "Getting NetBios name"
        $sourcenetbios = Get-NetBiosName $sourceserver
        
        Write-Output "Checking if remote access is enabled"
        winrm id -r:$sourcenetbios 2>$null | Out-Null
        
        if ($LastExitCode -ne 0) 
        { 
            throw "Remote PowerShell access not enabled on on $source or access denied. Windows admin acccess required. Quitting." 
        }
        
        Write-Output "Checking if Remote Registry is enabled"
        try 
        { 
            Invoke-Command -ComputerName $sourcenetbios { Get-ItemProperty -Path "HKLM:\SOFTWARE\" } 
        }
        catch 
        { 
            throw "Can't connect to remote registry on $source. Quitting." 
        }
        
        Copy-Credential $sourceserver $destserver -Credentials $credentials -force:$force
        
    }
    
    END
    {
        $sourceserver.ConnectionContext.Disconnect()
        $destserver.ConnectionContext.Disconnect()
        If ($Pscmdlet.ShouldProcess("console", "Showing finished message")) { Write-Output "Credential migration finished" }
    }
}