{"id":1415,"date":"2016-11-14T09:08:02","date_gmt":"2016-11-14T07:08:02","guid":{"rendered":"http:\/\/hen.co.za\/blog\/?p=1415"},"modified":"2016-11-14T18:56:11","modified_gmt":"2016-11-14T16:56:11","slug":"ssh-from-powershell","status":"publish","type":"post","link":"https:\/\/hen.co.za\/blog\/2016\/11\/ssh-from-powershell\/","title":{"rendered":"SSH from PowerShell"},"content":{"rendered":"

I’ve been playing with more non Microsoft technologies recently and even have a few Linux VMs running here and there. In the process I’ve learned a lot about interacting between the two worlds\/environments using technologies like SSH and even running the Powershell Alpha previews on my Linux VMs. Then I got ‘bored’ and looked for a way to programmatically interact with my VMs (for monitoring) and discovered the open source project SSH.Net<\/a> which I now have incorporated into even QuickMon<\/a>. Then I got even more bored and started looking for a way to use SSH from Powershell and came across the SSH-Sessions<\/a> module which incidentally also use SSH.Net to give Powershell a way to call\/connect using SSH.<\/p>\n

No PassPhrase<\/strong><\/p>\n

This all works nicely except… SSH-Sessions had one shortcoming.. which I just had to fix. The creator(s) of this module implements a way to specify a key file when connecting to an SSH server but does not provide a way to specify the ‘PassPhrase’ at all! WHY?<\/p>\n

Any way, I knew the SSH.Net library does support it since I actually make use of this functionality in QuickMon. Then I started digging inside the SSH-Session script files and made a few adjustments…<\/p>\n

Fix<\/strong><\/p>\n

To enable PassPhrase functionality I simply had to add the following code in the ‘New-SshSession’ function:<\/p>\n

Change the function header to:<\/p>\n

\r\nfunction New-SshSession {\r\n    param([Parameter(Mandatory=$true)][string[]] $ComputerName,\r\n          [Parameter(Mandatory=$true)][string]   $Username,\r\n          [string] $KeyFile = '',\r\n          [string] $PassPhrase = 'blankPassphrase',\r\n          [string] $Password = 'SvendsenTechDefault', # I guess allowing for a blank password is "wise"...          \r\n          [int] $Port = 22,\r\n          [switch] $Quiet\r\n    )\r\n<\/pre>\n
and then inside the function:<\/p>\n
\r\nif ($KeyFile -ne '') {\r\n        if (-not $Quiet) {\r\n            "Key file specified. Will override password. Trying to read key file..."\r\n        }\r\n        if ($PassPhrase -eq 'blankPassphrase') {\r\n            $SecurePassPhrase = Read-Host -AsSecureString "key provided. Please enter pass phrase for $KeyFile"\r\n            $PassPhrase = ConvertFrom-SecureToPlain $SecurePassPhrase\r\n        }\r\n        if (Test-Path -PathType Leaf -Path $Keyfile) {\r\n            $Key = New-Object Renci.SshNet.PrivateKeyFile( $Keyfile, $PassPhrase ) -ErrorAction Stop\r\n        }\r\n        else {\r\n            "Specified keyfile does not exist: '$KeyFile'."\r\n            return\r\n        }   \r\n    }\r\n<\/pre>\n
Example<\/strong><\/p>\n
And with the you can now use the module to connect to SSH using a Key file that has a PassPhrase. If you don’t specify the PassPhrase the script will prompt you for one. If you actually don’t have a PassPhrase at all then pass an empty string as the value of PassPhrase (not tested but it should work).<\/p>\n
\r\nImport-Module SSH-Sessions\r\nNew-SshSession -Computer mySSHServer -Username me  -KeyFile 'c:\\mykeys\\mykey.key' -PassPhrase 'somePhrase'\r\nInvoke-SshCommand  -ComputerName mySSHServer -Command "cat \/proc\/cpuinfo | grep processor" -Quiet\r\nRemove-SshSession -RemoveAll -Quiet\r\n<\/pre>\n","protected":false},"excerpt":{"rendered":"
I’ve been playing with more non Microsoft technologies recently and even have a few Linux VMs running here and there. In the process I’ve learned a lot about interacting between the two worlds\/environments using technologies like SSH and even running …<\/p>\n
Read more »<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[267,16],"tags":[240,311],"class_list":["post-1415","post","type-post","status-publish","format-standard","hentry","category-administration","category-reference","tag-powershell","tag-ssh"],"_links":{"self":[{"href":"https:\/\/hen.co.za\/blog\/wp-json\/wp\/v2\/posts\/1415","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/hen.co.za\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/hen.co.za\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/hen.co.za\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/hen.co.za\/blog\/wp-json\/wp\/v2\/comments?post=1415"}],"version-history":[{"count":8,"href":"https:\/\/hen.co.za\/blog\/wp-json\/wp\/v2\/posts\/1415\/revisions"}],"predecessor-version":[{"id":1423,"href":"https:\/\/hen.co.za\/blog\/wp-json\/wp\/v2\/posts\/1415\/revisions\/1423"}],"wp:attachment":[{"href":"https:\/\/hen.co.za\/blog\/wp-json\/wp\/v2\/media?parent=1415"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/hen.co.za\/blog\/wp-json\/wp\/v2\/categories?post=1415"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/hen.co.za\/blog\/wp-json\/wp\/v2\/tags?post=1415"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}