What is PowerShell? Things to know about PowerShell Code Signing

With the increase in automation, PowerShell scripts are rapidly coming into action. Every industry utilizes some software, running scripts in the background to ease core operations.

Whenever companies or users have to run any script, the first task is verifying its legitimacy. And the best method to do so is by checking the publisher’s signature.

PowerShell Code Signing Certificates are highly utilized as every scripter, developer, and publisher wants to grow. It aids them in tamper-proofing their scripts and building strong trust with their customers.

But, there are a few factors that you should never forget before you digitally sign PowerShell scripts With a Code Signing.

And further, you will understand everything you need to know about PowerShell Code Signing. So, let’s get started.

What are PowerShell and PowerShell Scripts?

PowerShell is a Microsoft Windows Command Line tool that helps users access, manage, modify, and maintain core libraries. It only accepts pre-defined command structures to execute queries through its interactive interface.

In addition, PowerShell also works as a scripting language. Developers utilize its pre-defined object-oriented syntax and semantics to write scripts.

The primary purpose of such scripts is to automate tasks and reduce user effort in performing core system operations. Moreover, DevOps engineers highly utilize PowerShell scripts to streamline the CI/CD ecosystems.

The Need To Digitally Sign PowerShell Scripts

Every publisher and developer must sign their PowerShell scripts, as it aids:

To Secure Scripts

When you sign PowerShell scripts, the procedure running in the background converts the source code into an encrypted hash digest. Due to it, malicious actors get disabled from reading the code and making unauthorized modifications.

In addition, the Windows operating system also treats the script as legitimate and runs it seamlessly.

To run only Legitimate Scripts

Every firm wants to run only secure scripts on its organizational network. And for appropriately fulfilling such tasks, companies depend upon the system’s executable file-checking mechanism. If your PowerShell script has a digital signature, the system will allow it to run. Otherwise, it will display a warning message or block its execution.

Therefore, signing is essential to make systems secure and increase productivity.

To Boost User Trust in Your Business

While installing applications, end-users have the probability of facing an Unknown Publisher Warning. But, when they don’t face it, their trust in the brand name boosts up. And it can happen for your business if you sign the PowerShell script.

By signing the script, the system will effortlessly assess your authenticity, leading to a zero warning installation for your customers.

To Make Scripts Valid Throughout a Lifetime

With the digital signing of PowerShell scripts, Code Signing Certificates also leverage timestamp functionality. It helps you add date and time details to the script about when the publisher signed it. And whenever the device finds a timestamp with the script, it treats it as valid, even if its digital certificate is expired.

Aspects To Consider Before Signing The PowerShell Scripts

Before digitally signing PowerShell scripts, you must consider the following factors for seamless and secure execution.

The Version of PowerShell

Having a full-updated Microsoft PowerShell version must be one of your topmost priorities. Leading certificate authorities, like Comodo and Certera, consistently upgrade their digital certificates to the latest standards.

If you want to execute certificate operations accurately, you need to have an updated PowerShell. In addition, the latest version is highly secure than the previous or outdated versions.

Hence, you must update your PowerShell with the latest version from Microsoft.

Private Key Utilization

You must check the usage frequency before signing or utilizing a specific PowerShell Code Signing Certificate. It will help you to obtain a particular number for how many other executable files the same keys are getting used.

As per security experts, you must use a specific private key for limited files to prevent heavy losses if a breach happens. Therefore, you should define and limit private key usage according to requirements or purchase a new Code Signing Certificate.

The Authenticity of the Code Signing Certificate

You must select the Code Signing Certificate of a recognized Certificate Authority, which follows all the CA/B Forum policies. It will help you to effectively sign and timestamp your PowerShell scripts, ensuring running them on different Windows versions.

Additionally, selecting EV Code Signing Certificate must be your first choice to prevent your users from facing a SmartScreen warning.

Scripts Assessment and Log Maintenance

PowerShell scripts must get checked before the final signing. You must check their functionality and verify the code blocks according to your requirements. And if you find anything suspicious, you must validate its integration.

Furthermore, record the process executor’s credentials, system details, signing date, and time whenever you perform the digital signing process. It will help you find the root cause if anything unexpected happens.

The Role of Execution Policies In Running Scripts

PowerShell allows the execution of secure and signed scripts. And to support it, PowerShell comes with different execution modes or policies. You have to provide your script according to the default policy on your client’s system.

The PowerShell Execution Policies are:

Restricted Policy

While the restricted policy runs, you cannot run any PowerShell script. It only permits running fundamental commands on the client system. Files with extensions .ps1xml, .psm1, and .ps1 get blocked from running.

RemoteSigned Policy

RemoteSigned policy gets by-default enabled on the server computer systems. It runs any local and downloaded script. It allows PowerShell to run local scripts without checking the Code Signing Certificate. However, for the downloaded ones, the digital certificate is mandatory.

AllSigned Policy

PowerShell with AllSigned policy runs every script from internal and external sources if it has a valid publisher’s sign. Although, professionals always consider downloading scripts from legit sources to prevent malicious scripts from running on your local system.

Unrestricted Policy

Unrestricted policy gets configured chiefly for testing purposes. Developers enable it to test the scripts before signing, as it allows the execution of unsigned scripts and configuration files. But you should never use it for any other purpose to prevent malicious scripts from spreading malware or corrupting your system.

PowerShell Code Signing Certificate: Where, Why, and How?

Finding a PowerShell Code Signing Certificate is always a time-consuming task. But, with SignMyCode, it has become an easy process, getting completed in three easy steps.

SignMyCode offers PowerShell Code Signing Certificates from reputed Certificate Authorities, such as DigiCert, Comodo, Sectigo, and Certera. Various solutions are available at all three validation levels, IV, OV, and EV.

Concluding Up

PowerShell scripts, while running, access the core directories and files to perform automated operations. And it makes it necessary for publishers to sign their scripts.

Otherwise, the end-user will block it or display a warning. In addition, developers must verify the script’s authenticity and code signing certificate before integrating digital signatures.

Search