Powershell security restrictions

Powershell has a number of security restrictions out of the box to keep malicious code from running and also (I would assume) to protect the user.  The first thing you will notice is that powershell will not run a script without the full path to the script defined.  This means that even if you are in the folder with the script in it, powershell cannot run it.

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PS script.ps1

The term 'script.ps1' is not recognized as a cmdlet, function, operable program, or script file. Verify the term and try again.
At line:1 char:10
+ script.ps1 <<<<

This script will need to be referenced like so:

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PS .\script.ps1

or

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PS D:\script.ps1

The next thing you will notice is that by default, a lot (see ALL) of your scripts fail with something similar to:

File D:\script.ps1 cannot be loaded because the execution of scripts is disabled on this system. Please see "get-help about_signing" for more details.
At line:1 char:12
+ .\script.ps1 <<<<

This is because by default, powershell has its execution policy set to Restricted.  This is extreamly secure, however it also makes it very difficult to do anything (ie. You literally cannot run scripts in Powershell with it like this):

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PS executionpolicy

Restricted

There are four levels of security in PowerShell…Restricted (default), AllSigned, RemoteSigned, and Unrestricted. 

• Restricted is extremely restricting. 
• AllSigned will only run scripts with a digital signature in them which, unless you get your script from Microsoft, is pretty much nothing. 
• RemoteSigned will run scripts locally that are not signed, however attempting to run remote scripts requires that they are signed. 
• Unrestricted is the last level, which will run anything (this is not recommended due to massive security issues). 

My recommendation is using RemoteSigned.  This allows you to run scripts locally without having to bother with digital signatures, however will not let remote scripts run to keep you secure.  You can set this by running the following:

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PS Set-ExecutionPolicy remotesigned
executionpolicy

RemoteSigned

Tags: powershell, Security