PowerShell is a powerful tool for automation and configuration management, used extensively by administrators and developers. One of its key features is the Execution Policy, which governs the conditions under which scripts and configuration files are executed. This policy is crucial for security, helping to prevent the accidental execution of potentially harmful scripts.
What is Execution Policy?
PowerShell’s execution policy helps to protect users from running potentially dangerous scripts. The policy controls the level of trust required for scripts to execute. Here are the different execution policies:
- AllSigned: Requires all scripts and configuration files to be signed by a trusted publisher, including those created locally.
- Bypass: No restrictions are applied; no warnings or prompts are given when running scripts.
- Default: Sets the default execution policy based on the system type. For Windows clients, it defaults to
Restricted; for Windows servers, it defaults toRemoteSigned. - RemoteSigned: Requires scripts and configuration files downloaded from the internet to be signed by a trusted publisher. Local scripts do not need to be signed.
- Restricted: Prevents all scripts from running and does not load configuration files. This is the default policy for Windows client computers.
- Undefined: No execution policy is set for the scope. If all scopes are set to
Undefined, the effective policy isRestricted. - Unrestricted: Allows all scripts to run and loads all configuration files. For scripts downloaded from the internet, a prompt appears asking for permission before running. This is the default policy for non-Windows computers starting from PowerShell 6.0 and cannot be changed.
For a detailed explanation of each policy, see Microsoft’s Execution Policy Documentation.
Viewing Current Execution Policies
To view the current execution policies applied at different scopes, use the following command:
Get-ExecutionPolicy -ListThis command lists the execution policies for each scope, such as MachinePolicy, UserPolicy, Process, CurrentUser, and LocalMachine. It helps you understand the effective policy in use and troubleshoot any issues related to script execution.
Setting Execution Policy to Unrestricted for CurrentUser
Sometimes, you might need to bypass the execution policy temporarily, especially when running a trusted script that does not comply with the current policy. You can set the execution policy to Unrestricted for the CurrentUser scope with the following command:
Set-ExecutionPolicy -Scope CurrentUser -ExecutionPolicy UnrestrictedRisks
While bypassing the execution policy can be useful in certain scenarios, it also poses security risks. Allowing all scripts to run without any restrictions can expose your system to potential threats. Therefore, it is essential to understand the implications of changing the execution policy and ensure that you trust the source of the scripts you are running. Always revert to a more restrictive policy once you have completed the task that required bypassing the policy.