Fix OpenSSH private key permissions on Windows (Solves Windows SSH: Permissions for 'private-key' are too open)

fix_windows_ssh_privkey_permission.ps1

param (
    [Parameter(Mandatory=$true)]
    [string]$privateKeyFilePath
)

# Remove inheritance from the private key file to prevent inheriting permissions from parent directories
. icacls $privateKeyFilePath /c /t /Inheritance:d

# Grant full control to the current user for keys within the user profile directory
. icacls $privateKeyFilePath /c /t /Grant ${env:UserName}:F

# If the private key is outside the user profile directory, take ownership and grant full control
. takeown /F $privateKeyFilePath
. icacls $privateKeyFilePath /c /t /Grant:r ${env:UserName}:F

# Remove all users' permissions except for the owner (current user)
. icacls $privateKeyFilePath /c /t /Remove:g Administrator "Authenticated Users" BUILTIN\Administrators BUILTIN Everyone System Users

# Verify and display the current permissions on the private key file
. icacls $privateKeyFilePath

# Remove the variable holding the private key path to clear sensitive information
Remove-Variable -Name privateKeyFilePath