PowerShell is a powerful task automation and configuration management framework from Microsoft, consisting of a command-line shell and scripting language built on .NET. In many scenarios, administrators need to run PowerShell scripts under different user credentials for security, testing, or deployment purposes. This tutorial will cover how to launch PowerShell as another user and automatically run a script when it starts.
Understanding the Requirements
To achieve this functionality, you need to understand two key concepts:
- Running PowerShell with Different Credentials: This involves using the
Start-Processcmdlet with the-Credentialparameter to specify the user under whose context PowerShell should run. - Launching a Script Automatically: Once PowerShell is launched under the desired credentials, you want it to execute a specific script automatically. This can be achieved by passing the path to the script as an argument to
powershell.exe.
Creating a Secure Credential
Before running PowerShell with different credentials, you need to create a secure credential object that contains the username and password of the user under whom PowerShell will run. You can do this using the ConvertTo-SecureString cmdlet to convert your plaintext password into a secure string.
$username = "domain\service.account"
$password = "yourpassword" # Replace with your actual password
$securePassword = ConvertTo-SecureString $password -AsPlainText -Force
$credential = New-Object System.Management.Automation.PSCredential $username, $securePassword
Launching PowerShell and Running a Script
With the credential object ready, you can now launch PowerShell under those credentials and specify a script to run automatically. The -ArgumentList parameter of Start-Process is used to pass arguments to the new process, in this case, the path to your PowerShell script.
$scriptPath = "\\\\domain.local\\location\\location\\location\\Script\\script.ps1"
Start-Process powershell.exe -Credential $credential -ArgumentList ("-file", $scriptPath)
Note: When specifying paths in PowerShell, it’s common to use double backslashes (\\) to escape the backslash character.
Alternative Method Using Verb RunAs
In some cases, you might need to explicitly specify the RunAs verb when starting the process. This can be particularly useful if you’re dealing with UAC (User Account Control) prompts or specific security policies on your system.
Start-Process powershell.exe -Credential $credential -Verb RunAs -ArgumentList ("-file", $scriptPath)
Best Practices and Security Considerations
When working with credentials and running scripts under different user contexts, it’s crucial to follow best practices for security:
- Secure Your Passwords: Always use secure strings for passwords and avoid hardcoding them in your scripts.
- Least Privilege Principle: Run PowerShell (and its scripts) with the least privileges necessary to perform the required tasks.
- Test Your Scripts: Thoroughly test your scripts in a controlled environment before deploying them, especially when they’re designed to run under different user credentials.
Conclusion
Launching PowerShell as another user and running scripts is a powerful capability that can streamline administrative tasks, improve security, and enhance automation processes. By following the steps outlined in this tutorial and adhering to best practices for security and scripting, you can effectively utilize this functionality in your environment.