Get-NetCertificate.ps1
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<#
.Synopsis Get the TLS certificate from a remote server. .DESCRIPTION Obtain the TLS certificate from a remote server by name or IP address and TCP port. .PARAMETER ComputerName Specify the DNS name or IP address of the URL you want to query. .PARAMETER Port Specify the port of the destination server. .EXAMPLE Get-NetCertificate -ComputerName www.google.com -Port 443 .EXAMPLE Get-NetCertificate -IP 8.8.8.8 -Port 853 .NOTES Adapted by: Jason Wasser Original code by: Rob VandenBrink Inspiration https://isc.sans.edu/forums/diary/Assessing+Remote+Certificates+with+Powershell/20645/ Modified: 1/9/2020 02:16:05 PM # Need to verify if this supports server name indication (SNI) for certificates #> function Get-NetCertificate { Param ( [Alias('IP')] [string]$ComputerName, [int]$Port=443 ) $TCPClient = New-Object -TypeName System.Net.Sockets.TCPClient try { $TcpSocket = New-Object Net.Sockets.TcpClient($ComputerName, $Port) $tcpstream = $TcpSocket.GetStream() $Callback = { param($sender, $cert, $chain, $errors) return $true } $SSLStream = New-Object -TypeName System.Net.Security.SSLStream -ArgumentList @($tcpstream, $True, $Callback) try { $SSLStream.AuthenticateAsClient($ComputerName) $Certificate = New-Object System.Security.Cryptography.X509Certificates.X509Certificate2($SSLStream.RemoteCertificate) } finally { $SSLStream.Dispose() } } finally { $TCPClient.Dispose() } Write-Output $Certificate } |