With all the SSL vulnerabilities that have come out recently, we've decided to disable some of the older protocols at work so we don't have to worry about them. After getting our group policies setup the way we wanted, we needed a way to validate that the protocols we wanted to disable were actually disabled on our servers.
Here is the script that I came up with, it tries to create an SslStream to the server using all the protocols defined in System.Security.Authentication.SslProtocols and outputs which were successful.
<#
.DESCRIPTION
Outputs the SSL protocols that the client is able to successfully use to connect to a server.
.NOTES
Copyright 2014 Chris Duck
http://blog.whatsupduck.net
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
.PARAMETER ComputerName
The name of the remote computer to connect to.
.PARAMETER Port
The remote port to connect to. The default is 443.
.EXAMPLE
Test-SslProtocols -ComputerName "www.google.com"
ComputerName : www.google.com
Port : 443
KeyLength : 2048
SignatureAlgorithm : rsa-sha1
Ssl2 : False
Ssl3 : True
Tls : True
Tls11 : True
Tls12 : True
#>
function Test-SslProtocols {
param(
[Parameter(Mandatory=$true,ValueFromPipelineByPropertyName=$true,ValueFromPipeline=$true)]
$ComputerName,
[Parameter(ValueFromPipelineByPropertyName=$true)]
[int]$Port = 443
)
begin {
$ProtocolNames = [System.Security.Authentication.SslProtocols] | gm -static -MemberType Property | ?{$_.Name -notin @("Default","None")} | %{$_.Name}
}
process {
$ProtocolStatus = [Ordered]@{}
$ProtocolStatus.Add("ComputerName", $ComputerName)
$ProtocolStatus.Add("Port", $Port)
$ProtocolStatus.Add("KeyLength", $null)
$ProtocolStatus.Add("SignatureAlgorithm", $null)
$ProtocolNames | %{
$ProtocolName = $_
$Socket = New-Object System.Net.Sockets.Socket([System.Net.Sockets.SocketType]::Stream, [System.Net.Sockets.ProtocolType]::Tcp)
$Socket.Connect($ComputerName, $Port)
try {
$NetStream = New-Object System.Net.Sockets.NetworkStream($Socket, $true)
$SslStream = New-Object System.Net.Security.SslStream($NetStream, $true)
$SslStream.AuthenticateAsClient($ComputerName, $null, $ProtocolName, $false )
$RemoteCertificate = [System.Security.Cryptography.X509Certificates.X509Certificate2]$SslStream.RemoteCertificate
$ProtocolStatus["KeyLength"] = $RemoteCertificate.PublicKey.Key.KeySize
$ProtocolStatus["SignatureAlgorithm"] = $RemoteCertificate.SignatureAlgorithm.FriendlyName
$ProtocolStatus["Certificate"] = $RemoteCertificate
$ProtocolStatus.Add($ProtocolName, $true)
} catch {
$ProtocolStatus.Add($ProtocolName, $false)
} finally {
$SslStream.Close()
}
}
[PSCustomObject]$ProtocolStatus
}
}