PowerShell is a powerful scripting language and command-line tool that can be used to perform various tasks and functions on Windows computers. However, PowerShell can also pose security risks if not configured and used properly. Malicious scripts and commands can compromise the system, steal data, or cause damage. Therefore, it is important to enhance the security of PowerShell settings to prevent unauthorized or harmful actions. In this essay, we will discuss some of the PowerShell security features and how to use them.
Execution Policy
One of the PowerShell security features is the execution policy, which controls the conditions under which PowerShell loads configuration files and runs scripts. This feature helps prevent the execution of malicious scripts by restricting the sources and types of scripts that can be runhttps://www.windowscentral.com/how-manage-microsoft-defender-antivirus-powershell-windows-10. There are several execution policy levels, such as:
• Restricted: This is the default level for Windows clients. It prevents any scripts from running, except for interactive commands.
• AllSigned: This level allows only scripts that are signed by a trusted publisher to run.
• RemoteSigned: This level allows only scripts that are either signed by a trusted publisher or downloaded from the Internet to run.
• Unrestricted: This level allows any scripts to run, but warns the user before running scripts that are downloaded from the Internet.
• Bypass: This level disables the execution policy and allows any scripts to run without any warnings or prompts.
The execution policy can be set and changed using the Set-ExecutionPolicy cmdlet in PowerShell. For example, to set the execution policy to RemoteSigned, use the following command:
Set-ExecutionPolicy -ExecutionPolicy RemoteSigned
The execution policy can also be managed using Group Policy settings, which can override the local settings on the endpoint where the changes are deployed or madehttps://learn.microsoft.com/en-us/microsoft-365/security/defender-endpoint/use-powershell-cmdlets-microsoft-defender-antivirus?view=o365-worldwide.
Script Signing
Another PowerShell security feature is script signing, which is a process of attaching a digital signature to a script to verify its identity and integrity. Script signing helps ensure that the script has not been tampered with and that it comes from a trusted source. Script signing requires a code signing certificate, which can be obtained from a certificate authority (CA) or self-signed using PowerShell.
To sign a script using PowerShell, use the Set-AuthenticodeSignature cmdlet with the following syntax:
Set-AuthenticodeSignature -FilePath <script> -Certificate
For example, to sign a script named Test.ps1 with a self-signed certificate named MyCert, use the following command:
Set-AuthenticodeSignature -FilePath C:\Scripts\Test.ps1 -Certificate (Get-ChildItem Cert:\CurrentUser\My\MyCert)
To verify the signature of a signed script, use the Get-AuthenticodeSignature cmdlet with the following syntax:
Get-AuthenticodeSignature -FilePath <script path>
For example, to verify the signature of Test.ps1, use the following command:
Get-AuthenticodeSignature -FilePath C:\Scripts\Test.ps1
The output will show the status of the signature, such as Valid, UnknownError, NotSigned, or NotTrusted.
Remote Security
PowerShell also supports remote access and management of computers using PowerShell remoting. This feature allows users to run commands and scripts on remote computers using various protocols, such as WinRM (Windows Remote Management), SSH (Secure Shell), or WSMan (Web Services for Management)https://www.cisecurity.org/insights/white-papers/intel-insights-how-to-secure-powershell. However, remote access can also expose computers to potential attacks from unauthorized or malicious users. Therefore, it is important to configure and secure PowerShell remoting settings to prevent unauthorized access or misuse.
One of the ways to configure and secure PowerShell remoting is to use the Set-PSSessionConfiguration cmdlet, which can modify the security configuration for PowerShell remoting. For example, this cmdlet can be used to enable or disable remote access, specify who can access or run commands on remote computers, set authentication and encryption methods, and morehttps://learn.microsoft.com/en-us/powershell/scripting/learn/security-features?view=powershell-7.3.
To use this cmdlet, open PowerShell as an administrator and type the following command:
Set-PSSessionConfiguration -Name -Parameter
For example, to disable remote access for all users except administrators on a computer named Server01, use the following command:
Set-PSSessionConfiguration -Name Microsoft.PowerShell -SecurityDescriptorSddl “O:NSG:BAD:P(A;;GA;;;BA)”
To view the current configuration settings for PowerShell remoting, use the Get-PSSessionConfiguration cmdlet with the following syntax:
Get-PSSessionConfiguration -Name
For example, to view the configuration settings for Microsoft.PowerShell on Server01, use the following command:
Get-PSSessionConfiguration -Name Microsoft.PowerShell
Conclusion
PowerShell is a useful tool for managing and automating tasks on Windows computers. However, it can also pose security risks if not configured and used properly. Therefore, it is important to enhance the security of PowerShell settings to prevent unauthorized or harmful actions. Some of the PowerShell security features that can help achieve this goal are execution policy, script signing, and remote security. By using these features, users can control the conditions under which PowerShell loads configuration files and runs scripts, verify the identity and integrity of scripts, and configure and secure PowerShell remoting settings.
