Windows Sistemlerde SSL Sıkılaştırma

Merhabalar bu yazıda vereceğimiz script ile hem sızma testlerinde karşımıza çıkan ve sıkılaştırmaktan çoğu IT personelinin yorulduğu SSL sıkılaştırmasının kolay yolunu sizlere sunacağım.

NOT: Bu makaleyi uygulamadan önce lütfen kayıt defteri yedeğini almayı unutmayınız. Eski uygulamalar için SSL/TLS sıkılaştırmasından sonra iletişim kopmaları sorunu oluşacaktır. Bunun için lütfen yedek almayı unutmayınız.

Aşağıdaki powershell scriptinin amacı sistem üzerinde;
-Disable SSLv3, TLS1, TLS1.1
-Disable weak and medium cipher suites
-Hardening SCHANNEL and other HASH functions
-Activate TLS1.2 only
fonksiyonlarını yapmaktadır.

Scripti çalıştırdıktan sonra sistemi reboot etmeniz gerekmektedir. Aşağıda her bir adımda neler olduğunun ekran görüntülerini paylaşıyorum.

Scriptin doğrulamaları nmap aracı içerisinde ssl-enum-ciphers modülü kullanılarak yapılmıştır. Kullanılan komutlar aşağıdaki resimlerde belirtilmiştir.

Script çalıştırmadan önce

script çalıştırırken,

script çalıştırdıktan sonra,

serverı reboot ettikten sonra,

İlgili Kod:

#

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
New-ItemProperty -path 'HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\Multi-Protocol Unified Hello\Server' -name 'DisabledByDefault' -value 1 -PropertyType 'DWord' -Force | Out-Null
New-Item 'HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\Multi-Protocol Unified Hello\Client' -Force | Out-Null
New-ItemProperty -path 'HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\Multi-Protocol Unified Hello\Client' -name Enabled -value 0 -PropertyType 'DWord' -Force | Out-Null
New-ItemProperty -path 'HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\Multi-Protocol Unified Hello\Client' -name 'DisabledByDefault' -value 1 -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
New-ItemProperty -path 'HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\PCT 1.0\Server' -name 'DisabledByDefault' -value 1 -PropertyType 'DWord' -Force | Out-Null
New-Item 'HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\PCT 1.0\Client' -Force | Out-Null
New-ItemProperty -path 'HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\PCT 1.0\Client' -name Enabled -value 0 -PropertyType 'DWord' -Force | Out-Null
New-ItemProperty -path 'HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\PCT 1.0\Client' -name 'DisabledByDefault' -value 1 -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
New-ItemProperty -path 'HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 2.0\Server' -name 'DisabledByDefault' -value 1 -PropertyType 'DWord' -Force | Out-Null
New-Item 'HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 2.0\Client' -Force | Out-Null
New-ItemProperty -path 'HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 2.0\Client' -name Enabled -value 0 -PropertyType 'DWord' -Force | Out-Null
New-ItemProperty -path 'HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 2.0\Client' -name 'DisabledByDefault' -value 1 -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
New-ItemProperty -path 'HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 3.0\Server' -name 'DisabledByDefault' -value 1 -PropertyType 'DWord' -Force | Out-Null
New-Item 'HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 3.0\Client' -Force | Out-Null
New-ItemProperty -path 'HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 3.0\Client' -name Enabled -value 0 -PropertyType 'DWord' -Force | Out-Null
New-ItemProperty -path 'HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 3.0\Client' -name 'DisabledByDefault' -value 1 -PropertyType 'DWord' -Force | Out-Null
Write-Host 'SSL 3.0 has been disabled.'

# Disable 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 '0' -PropertyType 'DWord' -Force | Out-Null
New-ItemProperty -path 'HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.0\Server' -name 'DisabledByDefault' -value 1 -PropertyType 'DWord' -Force | Out-Null
New-Item 'HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.0\Client' -Force | Out-Null
New-ItemProperty -path 'HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.0\Client' -name 'Enabled' -value '0' -PropertyType 'DWord' -Force | Out-Null
New-ItemProperty -path 'HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.0\Client' -name 'DisabledByDefault' -value 1 -PropertyType 'DWord' -Force | Out-Null
Write-Host 'TLS 1.0 has been disabled.'

# Add and Disable 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-ItemProperty -path 'HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.1\Server' -name 'Enabled' -value '0' -PropertyType 'DWord' -Force | Out-Null
New-ItemProperty -path 'HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.1\Server' -name 'DisabledByDefault' -value 1 -PropertyType 'DWord' -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\Client' -name 'Enabled' -value '0' -PropertyType 'DWord' -Force | Out-Null
New-ItemProperty -path 'HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.1\Client' -name 'DisabledByDefault' -value 1 -PropertyType 'DWord' -Force | Out-Null
Write-Host 'TLS 1.1 has been disabled.'
 
# 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-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-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\Client' -name 'Enabled' -value '0xffffffff' -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.
$insecureCiphers = @(
  'DES 56/56',
  'NULL',
  'RC2 128/128',
  'RC2 40/128',
  'RC2 56/128',
  'RC4 40/128',
  'RC4 56/128',
  'RC4 64/128',
  'RC4 128/128',
  'Triple DES 168'
)
Foreach ($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. This is the last cipher supported by Windows XP.
# - Windows Vista and before 'Triple DES 168' was named 'Triple DES 168/168' per https://support.microsoft.com/en-us/kb/245030
$secureCiphers = @(
  'AES 128/128',
  'AES 256/256'
)
Foreach ($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' -Force | Out-Null
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
 
$secureHashes = @(
  'SHA',
  'SHA256',
  'SHA384',
  'SHA512'
)
Foreach ($secureHash in $secureHashes) {
  $key = (Get-Item HKLM:\).OpenSubKey('SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Hashes', $true).CreateSubKey($secureHash)
  New-ItemProperty -path "HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Hashes\$secureHash" -name 'Enabled' -value '0xffffffff' -PropertyType 'DWord' -Force | Out-Null
  $key.close()
  Write-Host "Hash $secureHash has been enabled."
}
 
# Set KeyExchangeAlgorithms configuration.
New-Item 'HKLM:SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\KeyExchangeAlgorithms' -Force | Out-Null
$secureKeyExchangeAlgorithms = @(
  'Diffie-Hellman',
  'ECDH',
  'PKCS'
)
Foreach ($secureKeyExchangeAlgorithm in $secureKeyExchangeAlgorithms) {
  $key = (Get-Item HKLM:\).OpenSubKey('SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\KeyExchangeAlgorithms', $true).CreateSubKey($secureKeyExchangeAlgorithm)
  New-ItemProperty -path "HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\KeyExchangeAlgorithms\$secureKeyExchangeAlgorithm" -name 'Enabled' -value '0xffffffff' -PropertyType 'DWord' -Force | Out-Null
  $key.close()
  Write-Host "KeyExchangeAlgorithm $secureKeyExchangeAlgorithm has been enabled."
}
 
# Microsoft Security Advisory 3174644 - Updated Support for Diffie-Hellman Key Exchange
# https://docs.microsoft.com/en-us/security-updates/SecurityAdvisories/2016/3174644
Write-Host 'Configure longer DHE key shares for TLS servers.'
New-ItemProperty -path "HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\KeyExchangeAlgorithms\Diffie-Hellman" -name 'ServerMinKeyBitLength' -value '2048' -PropertyType 'DWord' -Force | Out-Null
New-ItemProperty -path "HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\KeyExchangeAlgorithms\Diffie-Hellman" -name 'ClientMinKeyBitLength' -value '2048' -PropertyType 'DWord' -Force | Out-Null
 
# https://support.microsoft.com/en-us/help/3174644/microsoft-security-advisory-updated-support-for-diffie-hellman-key-exc
New-ItemProperty -path "HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\KeyExchangeAlgorithms\PKCS" -name 'ClientMinKeyBitLength' -value '2048' -PropertyType 'DWord' -Force | Out-Null
 
# Set cipher suites order as secure as possible (Enables Perfect Forward Secrecy).
$os = Get-WmiObject -class Win32_OperatingSystem
if ([System.Version]$os.Version -lt [System.Version]'10.0') {
  Write-Host 'Use cipher suites order for Windows 2008/2008R2/2012/2012R2.'
  $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_128_CBC_SHA256_P521',
    'TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P384',
    'TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_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_SHA_P521',
    '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_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_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_SHA_P521',
    'TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA_P384',
    'TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA_P256',
    # Below are the only AEAD ciphers available on Windows 2012R2 and earlier.
    # - RSA certificates need below ciphers, but ECDSA certificates (EV) may not.
    # - We get penalty for not using AEAD suites with RSA certificates.
    'TLS_RSA_WITH_AES_256_GCM_SHA384',
    'TLS_RSA_WITH_AES_128_GCM_SHA256',
    'TLS_RSA_WITH_AES_256_CBC_SHA256',
    'TLS_RSA_WITH_AES_128_CBC_SHA256',
    'TLS_RSA_WITH_AES_256_CBC_SHA',
    'TLS_RSA_WITH_AES_128_CBC_SHA'
  )
} else {
  Write-Host 'Use cipher suites order for Windows 10/2016 and later.'
  $cipherSuitesOrder = @(
    'TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384',
    'TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256',
    'TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384',
    'TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256',
    'TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA',
    'TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA',
    'TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384',
    'TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256',
    'TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384',
    'TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256',
    'TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA',
    'TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA'
  )
}
$cipherSuitesAsString = [string]::join(',', $cipherSuitesOrder)
# One user reported this key does not exists on Windows 2012R2. Cannot repro myself on a brand new Windows 2012R2 core machine. Adding this just to be save.
New-Item 'HKLM:\SOFTWARE\Policies\Microsoft\Cryptography\Configuration\SSL\00010002' -ErrorAction SilentlyContinue
New-ItemProperty -path 'HKLM:\SOFTWARE\Policies\Microsoft\Cryptography\Configuration\SSL\00010002' -name 'Functions' -value $cipherSuitesAsString -PropertyType 'String' -Force | Out-Null
 
# Exchange Server TLS guidance Part 2: Enabling TLS 1.2 and Identifying Clients Not Using It
# https://blogs.technet.microsoft.com/exchange/2018/04/02/exchange-server-tls-guidance-part-2-enabling-tls-1-2-and-identifying-clients-not-using-it/
# New IIS functionality to help identify weak TLS usage
# https://cloudblogs.microsoft.com/microsoftsecure/2017/09/07/new-iis-functionality-to-help-identify-weak-tls-usage/
Write-Host 'Enable TLS 1.2 for .NET 3.5 and .NET 4.x'
New-ItemProperty -path "HKLM:\SOFTWARE\Microsoft\.NETFramework\v2.0.50727" -name 'SystemDefaultTlsVersions' -value 1 -PropertyType 'DWord' -Force | Out-Null
New-ItemProperty -path "HKLM:\SOFTWARE\Microsoft\.NETFramework\v2.0.50727" -name 'SchUseStrongCrypto' -value 1 -PropertyType 'DWord' -Force | Out-Null
New-ItemProperty -path "HKLM:\SOFTWARE\Microsoft\.NETFramework\v4.0.30319" -name 'SystemDefaultTlsVersions' -value 1 -PropertyType 'DWord' -Force | Out-Null
New-ItemProperty -path "HKLM:\SOFTWARE\Microsoft\.NETFramework\v4.0.30319" -name 'SchUseStrongCrypto' -value 1 -PropertyType 'DWord' -Force | Out-Null
if (Test-Path 'HKLM:\SOFTWARE\Wow6432Node') {
  New-ItemProperty -path "HKLM:\SOFTWARE\Wow6432Node\Microsoft\.NETFramework\v2.0.50727" -name 'SystemDefaultTlsVersions' -value 1 -PropertyType 'DWord' -Force | Out-Null
  New-ItemProperty -path "HKLM:\SOFTWARE\Wow6432Node\Microsoft\.NETFramework\v2.0.50727" -name 'SchUseStrongCrypto' -value 1 -PropertyType 'DWord' -Force | Out-Null
  New-ItemProperty -path "HKLM:\SOFTWARE\Wow6432Node\Microsoft\.NETFramework\v4.0.30319" -name 'SystemDefaultTlsVersions' -value 1 -PropertyType 'DWord' -Force | Out-Null
  New-ItemProperty -path "HKLM:\SOFTWARE\Wow6432Node\Microsoft\.NETFramework\v4.0.30319" -name 'SchUseStrongCrypto' -value 1 -PropertyType 'DWord' -Force | Out-Null
}
 
# DefaultSecureProtocols Value	Decimal value  Protocol enabled
# 0x00000008                                8  Enable SSL 2.0 by default
# 0x00000020                               32  Enable SSL 3.0 by default
# 0x00000080                              128  Enable TLS 1.0 by default
# 0x00000200                              512  Enable TLS 1.1 by default
# 0x00000800                             2048  Enable TLS 1.2 by default
$defaultSecureProtocols = @(
  '2048'  # TLS 1.2
)
$defaultSecureProtocolsSum = ($defaultSecureProtocols | Measure-Object -Sum).Sum
 
# Update to enable TLS 1.2 as a default secure protocols in WinHTTP in Windows
# https://support.microsoft.com/en-us/help/3140245/update-to-enable-tls-1-1-and-tls-1-2-as-a-default-secure-protocols-in
 
# Verify if hotfix KB3140245 is installed.
$file_version_winhttp_dll = (Get-Item $env:windir\System32\winhttp.dll).VersionInfo | % {("{0}.{1}.{2}.{3}" -f $_.ProductMajorPart,$_.ProductMinorPart,$_.ProductBuildPart,$_.ProductPrivatePart)}
$file_version_webio_dll = (Get-Item $env:windir\System32\Webio.dll).VersionInfo | % {("{0}.{1}.{2}.{3}" -f $_.ProductMajorPart,$_.ProductMinorPart,$_.ProductBuildPart,$_.ProductPrivatePart)}
if ([System.Version]$file_version_winhttp_dll -lt [System.Version]"6.1.7601.23375" -or [System.Version]$file_version_webio_dll -lt [System.Version]"6.1.7601.23375") {
  Write-Host 'WinHTTP: Cannot enable TLS 1.2. Please see https://support.microsoft.com/en-us/help/3140245/update-to-enable-tls-1-1-and-tls-1-2-as-a-default-secure-protocols-in for system requirements.'
} else {
  Write-Host 'WinHTTP: Minimum system requirements are met.'
  Write-Host 'WinHTTP: Activate TLS 1.2 only.'
  New-ItemProperty -path 'HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\WinHttp' -name 'DefaultSecureProtocols' -value $defaultSecureProtocolsSum -PropertyType 'DWord' -Force | Out-Null
  if (Test-Path 'HKLM:\SOFTWARE\Wow6432Node') {
    # WinHttp key seems missing in Windows 2019 for unknown reasons.
    New-Item 'HKLM:\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Internet Settings\WinHttp' -ErrorAction SilentlyContinue | Out-Null
    New-ItemProperty -path 'HKLM:\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Internet Settings\WinHttp' -name 'DefaultSecureProtocols' -value $defaultSecureProtocolsSum -PropertyType 'DWord' -Force | Out-Null
  }
}
 
Write-Host 'Windows Internet Explorer: Activate TLS 1.2 only.'
New-ItemProperty -path 'HKCU:\Software\Microsoft\Windows\CurrentVersion\Internet Settings' -name 'SecureProtocols' -value $defaultSecureProtocolsSum -PropertyType 'DWord' -Force | Out-Null
New-ItemProperty -path 'HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings' -name 'SecureProtocols' -value $defaultSecureProtocolsSum -PropertyType 'DWord' -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