In the ever continuing war against people reading traffic between client and server, every server administrator should give their clients the best protection they can give while not compromising usability.

To test your website for SSL strength you can use one of the most frequently used website namely: www.ssllabs.com/ssltest

After you have done any of the things I have posted below, you should test it and see if it indeed upgraded your score. Please not that it is always advisable to check this site regularly to see if the score you have still is in the range what you want it to be.

For server 2003 it can be quite a hassle. Since Microsoft will stop supporting this version, and does already not implement any new protocols etc. in the product, which will limit the cyphers and the protocols you can use on the server. I would recommend upgrading to at least Server 2008R2 or higher. Considering that it is not always possible it would be a good idea to at least do the following, which is to turn off SSL 2 and 3 using the registry. This can be changed by changing / adding the following keys:

Key:HKey_Local_Machine\System\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 2.0\Server
Dword: Enable
Value: 0

Key:HKey_Local_Machine\System\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 3.0\Server
Dword: Enable
Value: 0

Please note that SSLv2 should be disabled by default by all times. This can be done because even while Windows XP not updated SSLv3 is at least supported by all versions of Windows XP. If Windows XP is up-to-date it should also be able to use TLS1.0 and thus it can be safely assumed that you can turn off SSLv3, if the correct ciphers are still added.

If you are using Windows 2008 or higher however you can use the PowerShell script below. Please note that even though higher ciphers and protocols are included in this PowerShell script, server 2008 does not support TLS 1.1 or TLS 1.2 yet. For that you would require at least Server 2008R2.

The following PowerShell script can be used to make sure that you have the (at the moment of writing) highest security on SSL Labs.
Thanks to Alexander Hass who has build the script. Please read more at his website here.

# Copyright 2014, Alexander Hass
# http://www.hass.de/content/setup-your-iis-ssl-perfect-forward-secrecy-and-tls-12
#
# Version 1.4
# – RC4 has been disabled.
# Version 1.3
# – MD5 has been disabled.
# Version 1.2
# – Re-factored code style and output
# Version 1.1
# – SSLv3 has been disabled. (Poodle attack protection)

Write-Host ‘Configuring IIS with SSL/TLS Deployment Best Practices…’
Write-Host ‘——————————————————————————–‘

# Disable Multi-Protocol Unified Hello
New-Item ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\Multi-Protocol Unified Hello\Server’ -Force | Out-Null
New-ItemProperty -path ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\Multi-Protocol Unified Hello\Server’ -name Enabled -value 0 -PropertyType ‘DWord’ -Force | Out-Null
Write-Host ‘Multi-Protocol Unified Hello has been disabled.’

# Disable PCT 1.0
New-Item ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\PCT 1.0\Server’ -Force | Out-Null
New-ItemProperty -path ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\PCT 1.0\Server’ -name Enabled -value 0 -PropertyType ‘DWord’ -Force | Out-Null
Write-Host ‘PCT 1.0 has been disabled.’

# Disable SSL 2.0 (PCI Compliance)
New-Item ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 2.0\Server’ -Force | Out-Null
New-ItemProperty -path ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 2.0\Server’ -name Enabled -value 0 -PropertyType ‘DWord’ -Force | Out-Null
Write-Host ‘SSL 2.0 has been disabled.’

# NOTE: If you disable SSL 3.0 the you may lock out some people still using
# Windows XP with IE6/7. Without SSL 3.0 enabled, there is no protocol available
# for these people to fall back. Safer shopping certifications may require that
# you disable SSLv3.
#
# Disable SSL 3.0 (PCI Compliance) and enable “Poodle” protection
New-Item ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 3.0\Server’ -Force | Out-Null
New-ItemProperty -path ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 3.0\Server’ -name Enabled -value 0 -PropertyType ‘DWord’ -Force | Out-Null
Write-Host ‘SSL 3.0 has been disabled.’

# Add and Enable TLS 1.0 for client and server SCHANNEL communications
New-Item ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.0\Server’ -Force | Out-Null
New-ItemProperty -path ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.0\Server’ -name ‘Enabled’ -value ‘0xffffffff’ -PropertyType ‘DWord’ -Force | Out-Null
New-ItemProperty -path ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.0\Server’ -name ‘DisabledByDefault’ -value 0 -PropertyType ‘DWord’ -Force | Out-Null
Write-Host ‘TLS 1.0 has been enabled.’

# Add and Enable TLS 1.1 for client and server SCHANNEL communications
New-Item ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.1\Server’ -Force | Out-Null
New-Item ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.1\Client’ -Force | Out-Null
New-ItemProperty -path ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.1\Server’ -name ‘Enabled’ -value ‘0xffffffff’ -PropertyType ‘DWord’ -Force | Out-Null
New-ItemProperty -path ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.1\Server’ -name ‘DisabledByDefault’ -value 0 -PropertyType ‘DWord’ -Force | Out-Null
New-ItemProperty -path ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.1\Client’ -name ‘Enabled’ -value 1 -PropertyType ‘DWord’ -Force | Out-Null
New-ItemProperty -path ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.1\Client’ -name ‘DisabledByDefault’ -value 0 -PropertyType ‘DWord’ -Force | Out-Null
Write-Host ‘TLS 1.1 has been enabled.’

# Add and Enable TLS 1.2 for client and server SCHANNEL communications
New-Item ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Server’ -Force | Out-Null
New-Item ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Client’ -Force | Out-Null
New-ItemProperty -path ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Server’ -name ‘Enabled’ -value ‘0xffffffff’ -PropertyType ‘DWord’ -Force | Out-Null
New-ItemProperty -path ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Server’ -name ‘DisabledByDefault’ -value 0 -PropertyType ‘DWord’ -Force | Out-Null
New-ItemProperty -path ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Client’ -name ‘Enabled’ -value 1 -PropertyType ‘DWord’ -Force | Out-Null
New-ItemProperty -path ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Client’ -name ‘DisabledByDefault’ -value 0 -PropertyType ‘DWord’ -Force | Out-Null
Write-Host ‘TLS 1.2 has been enabled.’

# Re-create the ciphers key.
New-Item ‘HKLM:SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Ciphers’ -Force | Out-Null

# Disable insecure/weak ciphers.
$insecureCiphers = @(
‘DES 56/56’,
‘NULL’,
‘RC2 128/128’,
‘RC2 40/128’,
‘RC2 56/128’,
‘RC4 40/128’,
‘RC4 56/128’,
‘RC4 64/128’,
‘RC4 128/128’
)
Foreach ($insecureCipher in $insecureCiphers) {
$key = (Get-Item HKLM:\).OpenSubKey(‘SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Ciphers’, $true).CreateSubKey($insecureCipher)
$key.SetValue(‘Enabled’, 0, ‘DWord’)
$key.close()
Write-Host “Weak cipher $insecureCipher has been disabled.”
}

# Enable new secure ciphers.
# – RC4: It is recommended to disable RC4, but you may lock out WinXP/IE8 if you enforce this. This is a requirement for FIPS 140-2.
# – 3DES: It is recommended to disable these in near future.
$secureCiphers = @(
‘AES 128/128’,
‘AES 256/256’,
‘Triple DES 168/168’
)
Foreach ($secureCipher in $secureCiphers) {
$key = (Get-Item HKLM:\).OpenSubKey(‘SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Ciphers’, $true).CreateSubKey($secureCipher)
New-ItemProperty -path “HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Ciphers\$secureCipher” -name ‘Enabled’ -value ‘0xffffffff’ -PropertyType ‘DWord’ -Force | Out-Null
$key.close()
Write-Host “Strong cipher $secureCipher has been enabled.”
}

# Set hashes configuration.
New-Item ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Hashes\MD5’ -Force | Out-Null
New-ItemProperty -path ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Hashes\MD5’ -name Enabled -value 0 -PropertyType ‘DWord’ -Force | Out-Null

New-Item ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Hashes\SHA’ -Force | Out-Null
New-ItemProperty -path ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Hashes\SHA’ -name Enabled -value ‘0xffffffff’ -PropertyType ‘DWord’ -Force | Out-Null

# Set KeyExchangeAlgorithms configuration.
New-Item ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\KeyExchangeAlgorithms\Diffie-Hellman’ -Force | Out-Null
New-ItemProperty -path ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\KeyExchangeAlgorithms\Diffie-Hellman’ -name Enabled -value ‘0xffffffff’ -PropertyType ‘DWord’ -Force | Out-Null

New-Item ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\KeyExchangeAlgorithms\PKCS’ -Force | Out-Null
New-ItemProperty -path ‘HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\KeyExchangeAlgorithms\PKCS’ -name Enabled -value ‘0xffffffff’ -PropertyType ‘DWord’ -Force | Out-Null

# Set cipher suites order as secure as possible (Enables Perfect Forward Secrecy).
$cipherSuitesOrder = @(
‘TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P521’,
‘TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P384’,
‘TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P256’,
‘TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA_P521’,
‘TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA_P384’,
‘TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA_P256’,
‘TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P521’,
‘TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA_P521’,
‘TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P384’,
‘TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256’,
‘TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA_P384’,
‘TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA_P256’,
‘TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384_P521’,
‘TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384_P384’,
‘TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256_P521’,
‘TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256_P384’,
‘TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256_P256’,
‘TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384_P521’,
‘TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384_P384’,
‘TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA_P521’,
‘TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA_P384’,
‘TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA_P256’,
‘TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256_P521’,
‘TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256_P384’,
‘TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256_P256’,
‘TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA_P521’,
‘TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA_P384’,
‘TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA_P256’,
‘TLS_DHE_DSS_WITH_AES_256_CBC_SHA256’,
‘TLS_DHE_DSS_WITH_AES_256_CBC_SHA’,
‘TLS_DHE_DSS_WITH_AES_128_CBC_SHA256’,
‘TLS_DHE_DSS_WITH_AES_128_CBC_SHA’,
‘TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA’,
‘TLS_RSA_WITH_AES_256_CBC_SHA256’,
‘TLS_RSA_WITH_AES_256_CBC_SHA’,
‘TLS_RSA_WITH_AES_128_CBC_SHA256’,
‘TLS_RSA_WITH_AES_128_CBC_SHA’,
‘TLS_RSA_WITH_3DES_EDE_CBC_SHA’
)
$cipherSuitesAsString = [string]::join(‘,’, $cipherSuitesOrder)
New-ItemProperty -path ‘HKLM:\SOFTWARE\Policies\Microsoft\Cryptography\Configuration\SSL\00010002’ -name ‘Functions’ -value $cipherSuitesAsString -PropertyType ‘String’ -Force | Out-Null

Write-Host ‘——————————————————————————–‘
Write-Host ‘NOTE: After the system has been rebooted you can verify your server’
Write-Host ‘ configuration at https://www.ssllabs.com/ssltest/’
Write-Host “——————————————————————————–`n”

Write-Host -ForegroundColor Red ‘A computer restart is required to apply settings. Restart computer now?’
Restart-Computer -Force -Confirm

Leave a Reply

Your e-mail address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.