Verifying Local User Account Passwords

In the previous tip, we asked Active Directory to validate user account passwords. The same can be done with local accounts. Your PowerShell code can use local account passwords to manage access to scripts or partial script functionality. Of course, you could also use the code below to create your own brute-force password penetration tool.

Ensuring the Correct Username for a Local User Account

By default, below script uses your current user name. Make sure $UserName is the user account name for a local user account:

# specify local user name and password to test
$UserName = $env:USERNAME
$Password = Read-Host -Prompt "Enter password to test"

# test password
Add-Type -AssemblyName System.DirectoryServices.AccountManagement 
$type = [DirectoryServices.AccountManagement.ContextType]::Machine
$PrincipalContext = [DirectoryServices.AccountManagement.PrincipalContext]::new($type)
$PrincipalContext.ValidateCredentials($UserName,$Password)

Your learning points:

• PowerShell can ask the local Windows user database to verify a password. This way, you can use Passwords maintained by Windows to decide whether a script should execute or what it should the user enable to do
• Keep in mind that it is bad security practice to ask users for their passwords because they cannot know what you are going to do with their password.

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