Fixing Running PowerShell Scripts on Windows Server 2008 R2

Troubleshooting PowerShell Script Execution Restrictions

When dealing with Windows Server 2008 R2, users may encounter an error indicating that PowerShell script execution has been disabled on the machine. This problem can occur when attempting to launch a script using cmd.exe, even if the execution policy is set to Unrestricted.

Despite confirming that the execution policy is Unrestricted, scripts may still fail to run, generating annoyance and impeding development. This article will look at the most common causes of this problem and how to ensure that the script runs properly.

Understanding and implementing script execution policies in PowerShell.

The scripts given are intended to address the issue of PowerShell script execution being disabled on Windows Server 2008 R2. The first script sets the execution policy to Bypass for the current PowerShell session using Set-ExecutionPolicy -ExecutionPolicy. Bypass - Scope Process - Force. This command permits all scripts to run without restrictions temporarily. The script then navigates to the directory that contains the Management_Install.ps1 script and runs it with powershell.\Management_Install.ps1. This strategy ensures that the change in execution policy is only transitory and has no impact on the system's overall security posture.

The second script, a batch file, also sets the execution policy to Bypass but does so via the command line. To accomplish this, it runs powershell -Command "Set-ExecutionPolicy Bypass -Scope Process -Force". After modifying the execution policy, the script goes to the script directory and executes the PowerShell script with powershell -File.\Management_Install.ps1. The batch script concludes with a pause command, which keeps the command prompt window open and allows the user to view any output or error warnings. This strategy is beneficial for automating the procedure and incorporating it into bigger batch procedures.

Script signing and security in PowerShell

The third script example shows how to sign a PowerShell script to meet with more stringent execution policies. First, use New-SelfSignedCertificate to create a self-signed certificate. This certificate can then be exported using Export-Certificate and imported into trustworthy certificate stores via Import-Certificate. By adding the certificate to the TrustedPublisher and Root stores, the system will trust scripts signed with this certificate. The script Management_Install.ps1 is then signed using Set-AuthenticodeSignature.

Script signing ensures that only trusted scripts run on the system, adding an extra degree of protection. This method is especially effective in contexts with strict security needs and execution policies set to AllSigned or RemoteSigned. Administrators can reduce potential security concerns by signing scripts to confirm that they have not been tampered with and come from a trusted source. This technique combines security and functionality, allowing scripts to run while ensuring system integrity.

# Ensure the script execution policy is set to Bypass
Set-ExecutionPolicy -ExecutionPolicy Bypass -Scope Process -Force

# Navigate to the script directory
cd "C:\Projects\Microsoft.Practices.ESB\Source\Samples\Management Portal\Install\Scripts"

# Execute the PowerShell script
powershell .\Management_Install.ps1

@echo off

:: Set PowerShell execution policy to Bypass
powershell -Command "Set-ExecutionPolicy Bypass -Scope Process -Force"

:: Navigate to the script directory
cd "C:\Projects\Microsoft.Practices.ESB\Source\Samples\Management Portal\Install\Scripts"

:: Run the PowerShell script
powershell -File .\Management_Install.ps1

pause

# Sample script content
Write-Output "Executing Management Install Script"

# Save this script as Management_Install.ps1

# To sign the script, follow these steps:
# 1. Create a self-signed certificate (if you don't have one)
$cert = New-SelfSignedCertificate -DnsName "PowerShellLocalCert" -CertStoreLocation "Cert:\LocalMachine\My"

# 2. Export the certificate to a file
Export-Certificate -Cert $cert -FilePath "C:\PowerShellLocalCert.cer"

# 3. Import the certificate to Trusted Publishers and Trusted Root Certification Authorities
Import-Certificate -FilePath "C:\PowerShellLocalCert.cer" -CertStoreLocation "Cert:\LocalMachine\TrustedPublisher"
Import-Certificate -FilePath "C:\PowerShellLocalCert.cer" -CertStoreLocation "Cert:\LocalMachine\Root"

# 4. Sign the script with the certificate
Set-AuthenticodeSignature -FilePath .\Management_Install.ps1 -Certificate $cert

Ensure Script Execution Policy Compliance and System Security

When administering Windows Server 2008 R2, it is critical to understand the various execution policies available in PowerShell and how they affect script execution. PowerShell execution controls are intended to prohibit the execution of potentially hazardous scripts. The four major policies are: Restricted, AllSigned, RemoteSigned, and Unrestricted. The default policy is Restricted, which does not allow any scripts to run. AllSigned demands that all scripts and configuration files be signed by a trusted publisher. RemoteSigned mandates that all scripts and configuration files obtained from the internet be signed by a trustworthy publisher, while local scripts can run without a signature.

Understanding these regulations allows administrators to pick the appropriate level of security for their environment. In cases where scripts must be executed on a frequent basis, setting the policy to Unrestricted can be hazardous because it permits all scripts to run without limits. Instead, administrators should consider using RemoteSigned or AllSigned to strike a balance between security and functionality. Administrators can reduce the danger of malicious code execution by signing scripts and controlling certificates.