PowerShell is an essential tool for administrators to manage their servers. It’s full of features that make it easy, such as the ability to create scripts and run them on multiple machines. But if you’re not careful with its execution policies, PowerShell can do some really nasty things
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The “set-executionpolicy” is a PowerShell command that allows users to manage their execution policy. This command can be used to change the default execution policy, or create custom execution policies.
Have you ever tried to launch a PowerShell script and received the dreaded error message below? If that’s the case, you’ll require the Set-ExecutionPolicy cmdlet and this guide.
Error: PowerShell Script Execution Is Disabled
In this article, you’ll learn about PowerShell execution policies and how to use the Set-ExecutionPolicy cmdlet to control them. You’ll know not only how to execute scripts but also how to employ execution policies by the Conclusion of this article!
This course was developed with Windows PowerShell in mind, and all demos were done with it. Execution policies are not specific to Windows PowerShell, and they work in PowerShell 6+ in a similar way. However, if you’re using PowerShell 6+, you may notice minor variations in functionality.
What is an Execution Policy, and how does it work?
You’ve probably come across an execution policy if you’ve ever experienced the problem stated above. PowerShell execution policies are a security feature that prevents dangerous scripts from executing on your system. Execution rules do not restrict you from using the console as a shell to execute PowerShell code, but they do prevent script execution.
According to Microsoft, an execution policy is more of a gate that you may open and shut than a “security” mechanism. After all, as you’ll see later, you can simply go around a set execution policy.
The foundation of execution policies is trust. If you trust a script, it’s unlikely that it’s harmful. Script execution restrictions normally do not prohibit all scripts from being executed. Their main goal (especially when set up more precisely) is to verify that the script you’re executing is cryptographically signed with a certificate.
Managing X.509 Certificates is a related topic (For Mortals)
Scopes of the Execution Policy
Script execution is limited by execution rules, as you’ve seen, although PowerShell can run scripts in a variety of situations. PowerShell runs scripts in a user’s logged-in context, a global machine context, or within the scope of a single active PowerShell console through scheduled tasks launched as SYSTEM.
PowerShell supports five separate contexts or scopes for which you may design an execution policy to satisfy all of these circumstances.
- MachinePolicy – This policy only applies to one machine. It is configured by an Active Directory group policy object and affects all users that connect into that machine. It takes priority over all other scopes once declared.
- LocalMachine. The HKEY LOCAL MACHINE registry subkey stores the default scope, which affects all computer users. This scope is the default when you use Establish-ExecutionPolicy to set an execution policy.
The registry value HKEY LOCAL MACHINESOFTWAREMicrosoftPowerShell1ShellIdsMicrosoft.PowerShell stores the execution policy for LocalMachine.
- UserPolicy – An Active Directory group policy object specifies the UserPolicy scope, which impacts just one user on a machine. Set-ExecutionPolicy does not allow you to update this policy.
- CurrentUser. The HKEY CURRENT USER registry hive stores the CurrentUser policy scope, which specifies the execution policy just for the current user. Set-ExecutionPolicy does not allow you to update this policy.
The registry value HKEY CURRENT USERSOFTWAREMicrosoftPowerShell1ShellIdsMicrosoft.PowerShell stores the execution policy for CurrentUser.
- Process – The execution policy for a single PowerShell session for a single user is defined in this scope. You may create the most granular execution policy using the Process execution policy scope. Unlike other execution policies, this one is kept in the PSExecutionPolicyPreference environment variable rather than the registry.
Types of Execution Policies
There are multiple “security levels” in execution policies. The severity of the execution policy is determined by these degrees. For example, you may have an execution policy that does nothing; it’s deactivated, but you can also entirely disable script execution using an execution policy.
Let’s go through each of the options for configuring the security level of an execution policy, starting with the least restrictive and working our way up to the most stringent.
UnRestricted
The least restrictive policy is one that has no bearing on anything; it’s called UnRestricted. Policies that allow for unRestricted execution are effectively disabled. When an execution policy is set to UnRestricted, users may execute any script regardless of trust.
Bypass
An execution policy set to Bypass, like the UnRestricted type, blocks nothing.
While the Bypass and UnRestricted execution policy types have a similar effect, the Bypass execution policy type isn’t really a type. It doesn’t use a stated execution policy at all.
Undefined
Although not typically used, setting an execution policy to Undefined effectively removes it. PowerShell entirely removes all given execution policies from the assigned scope when you set an execution policy to Undefined.
The execution policy on non-Windows machines is always set to UnRestricted and cannot be modified.
PowerShell interprets all scopes as Restricted when all of them are set to Undefined.
RemoteSigned
As previously stated, execution rules are all about establishing confidence via the use of a digital signature on scripts. PowerShell also considers where the script originated. Is it something you made yourself or something you got from a random individual on the internet?
Scripts created on a machine other than your own should not be assumed to be trustworthy. This is why the RemoteSigned execution policy is available in PowerShell. To be cryptographically signed, all scripts must be written someplace other than your local computer, according to the RemoteSigned execution policy.
With the Unblock-File cmdlet, you may partially override this execution policy for files obtained from the Internet. In the The RemoteSigned Policy in Action section, you’ll learn more about this behavior.
RemoteSigned is set as the default policy for Windows Server.
AllSigned
Set the execution policy to AllSigned to guarantee that all PowerShell scripts are cryptographically signed. This execution policy, like RemoteSigned, takes the signature requirement a step further by requiring that all scripts be signed before execution.
You can still get around the execution policy by skipping it, even if you have the AllSigned execution policy configured, as you’ll see later.
Restricted
Restricted is the most restricted execution policy. When the execution policy is set to Restricted, no scripts may run, regardless of whether they are trusted or not. This policy effectively inhibits the execution of scripts.
The Restricted type also guarantees that PowerShell formatting and configuration files (PS1XML), module script files (PSM1), and PowerShell profiles cannot be executed, unlike the less restricted kinds.
Restricted execution is enabled by default on all Windows clients.
Although Microsoft specifies a seventh execution policy called Default, the type is simply a combination of RemoteSigned (Windows Server) and Restricted (Windows XP) (Windows Clients).
The RemoteSigned Policy in Action
The RemoteSigned execution policy is a good example of how this works. As you’ve learned, this execution policy stops scripts from executing that were produced on a machine other than your own from running.
However, how does PowerShell know that the script was written somewhere else? Streams of data
NTFS Data Streams: Understanding and Querying
When you create a file on an NTFS file system, the file is given the alternative data stream (ADS) property. $Data and zone are the two file properties of an ADS. Identifier. The zone is used by PowerShell. The Identifier attribute is used to determine if a PowerShell script file was produced elsewhere.
ADS characteristics, unlike other qualities like Compressed or Read Only, are concealed in File Explorer. However, you may explore these data streams using PowerShell.
As illustrated below, run the Get-Item cmdlet using the location of the script and the Stream option. Hello, World, in this case. On the local computer, ps1 was written. The Stream property has just one attribute added to it: $DATA. There is no such thing as an ADS attribute.
‘.Hello World.ps1’ Get-Item -Stream *
For a local file, use ADS Stream output.
Run the same command on a script that you obtained from the Internet. You’ll see that Get-Item now returns a new object with a Stream of Zone.Identifier.
ADS Stream output for an internet-downloaded PowerShell file
When you know a file has an ADS, you may use the Get-Content command to find out what zone it belongs to. The zone identifies the origin of the file.
-Stream zone.identifier Get-Content.Get-CertDetails.ps1
Get-Content returns a ZoneId value that represents the zone from which the file originated.
Value of Zone ID
Zone values that might be used are:
Zone Identification Zone ————————————————————————————————————————————— 0 Local Intranet Zone 1 My Computer 2 Trusted Sites Zone 4 Restricted Sites Zone 3 Internet Zone 3 Internet Zone 3 Internet Zone 3 Internet Zone 3 Internet Zone 3 Internet Zone 3 Internet Zone
Priority of Execution Policy
As previously stated, multiple alternative execution rules exist at the same time. When all of these execution policies are merged, the settings of your current session are determined. You must have precedence when you have several execution rules in place.
The sequence in which PowerShell implements distinct rules defined at different scopes is referred to as policy precedence. Some execution rules take precedence over others.
When you call Get-ExecutionPolicy -list is a cmdlet that returns a list of execution policies., you’ll get a list of all active execution policies, sorted by priority from lowest to highest. MachinePolicy, for example, will be overridden by the LocalMachine and CurrentUser policies since it has a lower priority.
The result of the cmdlet Get-ExecutionPolicy
Exercising Execution Policies
Now that you’ve learned about the history of execution rules, let’s look at how to use them. You have two commands at your disposal to interact with PowerShell’s execution policies. Get-ExecutionPolicy will show you what policies are presently specified, and Set-ExecutionPolicy will let you create new ones.
Obtaining Policies That Have Been Assigned Currently
Before you can start adjusting execution rules, you must first understand what you’re up against. You may accomplish this using the Get-ExecutionPolicy command. This command lists all of the policies that are presently allocated to a machine.
When you use the Get-ExecutionPolicy command on a PowerShell console without any arguments, it displays the current PowerShell session’s execution policy.
The result of the cmdlet Get-ExecutionPolicy
To view the execution policy results for a specific scope, use the Scope option with the name of the scope you want to see the results for.
-ScopeProcess Get-ExecutionPolicy -Scope LocalMachine Get-ExecutionPolicy
The Get-ExecutionPolicy cmdlet returns the result of the scope parameter.
Use the List argument to see all scopes and their execution rules, as illustrated below.
Get-ExecutionPolicy -list is a cmdlet that returns a list of execution policies.
The Get-ExecutionPolicy cmdlet returns a list of all scopes.
Changing Policies for Execution
You may adjust the execution policies that are presently allocated once you know what they are. The Set-ExecutionPolicy command may be used to alter the policy on a single machine. If you work for a company, though, you’ll want to make policy changes in bulk. If that’s the case, if you’re in an Active Directory domain, you’ll always have Group Policy.
Using the Set-ExecutionPolicy command
Let’s start with the Set-ExecutionPolicy command to adjust policies. Open PowerShell as an administrator to do so.
How to Run PowerShell as an Administrator is a related topic.
Run Set-ExecutionPolicy with just one argument (ExecutionPolicy) to provide the name of the execution policy.
-ExecutionPolicy RemoteSigned Set-ExecutionPolicy
After that, PowerShell will ask whether you want to modify the execution policy. If you do, press Enter after typing Y or A.
Policy of Execution Modification
Some PowerShell instructions need the execution of numerous additional commands in order to function. If you enter Y in the above example, PowerShell may urge you to continue for each step. If you hit A, the process will proceed for the rest of the phases.
Without Prompts, Run Set-ExecutionPolicy
When you execute Set-ExecutionPolicy by default, it will ask you whether you wish to modify the execution policy. By using the Force argument in your command, you may bypass this question. All confirmation prompts will be suppressed if the Force option is used.
-Force Set-ExecutionPolicy RemoteSigned
When the Force parameter is utilized, the Set-ExecutionPolicy command produces the following output.
Using the Registry to Configure PowerShell Execution Policy
Because most execution policies (excluding Process) are kept in the registry, you may alter them directly from there.
Using the registry, you may alter the execution policies:
- Open the Windows Registry Editor (regedit) or the registry editing tool of your choice.
Related:How to Get a Registry Value Using PowerShell
2. Update the registry key for the execution policy scope you want to change.
HKEY LOCAL MACHINESOFTWARE – LocalMachine MicrosoftPowerShell1ShellIdsMicrosoft.PowerShell
HKEY CURRENT USERSOFTWAREMicrosoft CurrentUser PowerShell1ShellIdsMicrosoft.PowerShell
3. Create a new string value named ExecutionPolicy by right-clicking on the registry entry.
4. Double-click the newly formed ExecutionPolicy string value and type in the name you want for the execution policy (Restricted, RemoteSigned, AllSigned, Unrestricted, or Undefined).
5. Make a new string value named Path in the same key. The path to the PowerShell engine is represented by the Path string value. Make that the Path parameter refers to the Windows PowerShell engine, which is C:WindowsSystem32WindowsPowerShellv1.0powershell.exe.
For the current user, the registry location for ExecutionPolicy is
A LocalMachine policy is overridden by the CurrentUser execution policy. If you attempt to update the execution policy using Set-ExecutionPolicy, which sets the policy at the LocalMachine scope by default, PowerShell will return the error displayed below.
Permission to execute the policy has been denied.
Using Group Policy to Control PowerShell Execution
If you work in an Active Directory environment, you probably won’t want to execute the Set-ExecutionPolicy cmdlet on all of your Windows computers. Instead, you may use Group Policy to manage rules in bulk.
What is a Group Policy, and How Does It Work?
To use GPO to control execution policies, follow these steps:
Make a Group Policy Object (GPO).
- On a domain controller or a domain-joined workstation, launch the Group Policy Management application.
Console for Managing Group Policies
2. Expand Domains —> <your Active Directory forest> —> Group Policy Objects.
Group Policy Objects is the node to choose.
3. Select Group Policy Objects from the context menu and select New.
4. Assign a name to your GPO. PowerShell Execution Policy is the name of the GPO in this tutorial.
Make a new Group Policy Object (GPO).
5. Select Edit from the context menu of the newly established GPO.
6. Select Computer ConfigurationPoliciesAdministrative Templates from the drop-down menu. Windows PowerShellWindows Components
Activate the Script Execution Policy feature.
8. Select the Enabled option in the Turn on Script Execution box. You may now choose from the following options:
9. Now, update the Execution Policy to the one you want.
- Allow only signed scripts to run – Allows all scripts to run if they are signed by a reputable publisher.
- Allows local scripts to function while requiring scripts received from the internet to be signed by a trustworthy publisher.
- Allow all scripts to execute — This option enables all scripts to run.
Execution Policy for Lists
Assign the Group Policy Object to the group.
After you’ve established the GPO, you’ll need to assign it to your target PCs. To do so, create an Active Directory Organizational Unit and attach the GPO to it (OU).
If you changed an existing GPO instead of establishing a new one, that GPO was most likely previously allocated to an OU.
- In Group Policy Management, navigate to your OU of choice by going to Domains —> <your Active Directory forest> —> <Your OU>.
2. Select Link an Existing GPO… from the right-click menu on the OU.
Connect to an Existing GPO…
3. Click OK after selecting the GPO you just defined (PowerShell Execution Policy).
Choose a GPO.
As indicated below, the GPO should now be allocated to the OU.
Create a link between the Group Policy Object and the Group Policy Object.
You may either wait for the Group Policy refresh interval to expire or force a refresh by using the gpupdate command on a target machine.
Related: [In-Depth] Understanding the GPUpdate Command
Changes in local policy are being stifled.
Local users may no longer alter the execution policy through the local PowerShell console after a GPO is in place that modifies it. If they attempt, they’ll get an error like the one below.
When manually modifying the execution policy, an error occurs.
Completely evading the Execution Policy
As previously stated, an execution policy isn’t always intended to be a security precaution. Why? Because there are a few methods to entirely avoid it if you want to.
Bypassing the execution policy using the -ExecutionPolicy Bypass Parameter
The Bypass policy, unlike the other execution policies, is normally specified in the PowerShell console rather to sent to the powershell.exe engine running as administrator.
Invoke powershell.exe, use the Bypass argument, and specify the file path as indicated below to execute a script named Hello World.ps1 totally bypassing any execution restrictions.
-executionpolicy bypass -file ‘.Hello World.ps1’ powershell.exe -executionpolicy bypass -file ‘.Hello World.ps1’
Bypass Execution Policy is a policy that allows you to bypass the execution of a command.
Raw Code Execution and Reading Scripts
You may also get around any execution policy by reading a script’s contents and then giving them straight to the PowerShell engine. As a result, each command is executed separately rather than as a full script.
The execution policy is set to Restricted, as seen below, but it still works by reading the script and forwarding it to powershell.exe.
This method is equivalent to choosing a line in a script in a PowerShell editor such as PowerShell ISE or Visual Studio Code and clicking F8.
| powershell.exe -noprofile Get-Content ‘.Hello World.ps1’
Another Way to Get Around the Execution Policy
Conclusion
By this point, you should be well-versed on PowerShell execution policies. Despite the fact that they aren’t strictly a security measure, you should nonetheless manage them in your business in accordance with your company’s standards.
PowerShell Execution Policies are a way to control how PowerShell behaves. This article will help you understand and manage the execution policy in powershell. Reference: how to change execution policy in powershell.
Frequently Asked Questions
What are the PowerShell execution policies?
A: There are few possible values for the PowerShell execution policy. The default value is Restricted, and it will only allow PowerShell to run commands in Windows batch files or scripts that were signed by Microsoft. If you want to execute all commands from any script, use RemoteSigned or Unrestricted policies.
What are executions policies in PowerShell and how many are there?
A: There are six different execution policies in PowerShell. These include Continue, Break, GoToNextStatement, Stop, WaitForExit and DisableSSH.
How do you set a PowerShell execution policy?
A: Get-ExecutionPolicy is the PowerShell cmdlet to use in order to set an execution policy.
Related Tags
- powershell execution policy unrestricted
- to run “.ps1” files, the execution policy must be set to
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