Solving Windows 11 Windows Defender Application Control and Device Guard Policies

Solving Windows 11 Windows Defender Application Control and Device Guard Policies

Understanding and Implementing Windows Defender Application Control (WDAC) in Windows 11

As an experienced IT professional, I often encounter questions and challenges around Windows Defender Application Control (WDAC) and Device Guard policies in the enterprise environment. These powerful security features in Windows 11 can be incredibly effective in protecting devices against malware and unauthorized software, but they can also be complex to set up and manage. In this comprehensive article, I’ll dive deep into the world of WDAC and provide practical tips and insights to help you solve common issues and implement these policies successfully in your organization.

Exploring the Basics of WDAC and Device Guard

WDAC, previously known as Configurable Code Integrity (CCI) and Device Guard, is a software-based security layer that enforces an explicit list of approved software that can run on a Windows 11 device. It’s designed to protect against malware and other untrusted programs by ensuring that only authorized code can execute.

Device Guard, on the other hand, is a hardware and software feature that works in conjunction with WDAC to provide an even more secure environment. By leveraging hardware-based virtualization, Device Guard can create a “virtual secure mode” that isolates the operating system from the rest of the system, further enhancing the protection against malicious code.

While WDAC and Device Guard are separate technologies, they are closely related and often used together to create a comprehensive application control solution in Windows 11. Understanding the differences and benefits of each is crucial when implementing these policies in your organization.

Deploying WDAC Policies with Configuration Manager

One of the most common ways to deploy WDAC policies in an enterprise environment is through Microsoft Endpoint Configuration Manager (formerly known as System Center Configuration Manager). Configuration Manager provides a user-friendly interface for creating, deploying, and monitoring WDAC policies across your managed devices.

To get started with WDAC using Configuration Manager, follow these steps:

1. Create an Application Control Policy: In the Configuration Manager console, navigate to the Assets and Compliance workspace, expand Endpoint Protection, and select the Windows Defender Application Control node. On the Home tab, click “Create Application Control Policy” to launch the wizard.

2. Configure the Policy Settings: In the wizard, you’ll be able to specify the enforcement mode (Enforcement Enabled or Audit Only), as well as any inclusions (authorized software or folders) that should be trusted. Make sure to thoroughly test the policy before deploying it to production devices.

3. Deploy the Policy: Once the policy is created, you can deploy it to your desired device collections. In the Configuration Manager console, select the policy, click “Deploy Application Control Policy,” and choose the target collection and schedule for the policy evaluation.

4. Monitor Policy Compliance: After deploying the WDAC policy, it’s essential to monitor its compliance and effectiveness. You can use the information in the Monitor compliance settings article to track the policy deployment status and investigate any issues that may arise.

One important consideration when deploying WDAC policies is the handling of software updates and new application installations. By default, WDAC only allows software changes that are deployed through the Configuration Manager client, which can create challenges for organizations that rely on automatic updates or third-party software installations.

To address this, you can either:

1. Authorize software trusted by the Intelligent Security Graph: This option allows WDAC to trust software that Microsoft has determined to be safe and trustworthy, based on its Intelligent Security Graph data.
2. Add trust for specific files or folders: If there are specific applications or folders that need to be trusted, you can manually add them to the WDAC policy’s inclusions.

Carefully planning and testing your WDAC policy deployment is crucial to avoid disrupting critical business applications or workflows.

Navigating Common WDAC Challenges

While WDAC and Device Guard offer robust security, they can also introduce some challenges that IT professionals need to be aware of and prepared to address. Let’s explore some of the common issues and potential solutions:

1. Unexpected Application Blocking

One of the most common issues with WDAC is when legitimate applications are unexpectedly blocked or prevented from running. This can happen when the WDAC policy is too restrictive or doesn’t account for all the necessary inclusions.

Solution: Thoroughly test your WDAC policy in a controlled environment before deploying it to production devices. Monitor the event logs for any blocked applications and carefully add the necessary inclusions to your policy to ensure critical software can still run.

2. Disabling WDAC or Device Guard

Users with local administrator rights may attempt to bypass or disable WDAC and Device Guard policies, potentially compromising the security measures you’ve put in place.

Solution: The only way to prevent users from disabling WDAC is to deploy a signed binary policy, which can be done through Group Policy but is not currently supported in Configuration Manager. Consider limiting local administrator access or implementing additional security controls to mitigate this risk.

3. Maintaining Compatibility with Software Updates and Deployments

As mentioned earlier, WDAC can create challenges for managing software updates and new application deployments, as it only trusts changes made through the Configuration Manager client.

Solution: Work closely with your application owners and development teams to ensure that any critical software updates or new deployments are properly included in your WDAC policy. Additionally, consider using the Intelligent Security Graph to automatically trust approved software updates.

4. Isolation of WDAC and Device Guard Policies

In some cases, you may want to apply different WDAC or Device Guard policies to specific collections of devices or users within your organization. This can be particularly useful for scenarios where you need more granular control over application access.

Solution: Leverage the flexibility of Configuration Manager to create and deploy multiple WDAC policies, each targeting specific device collections or user groups. This allows you to tailor the security controls to the unique needs of different parts of your organization.

5. Troubleshooting Policy Processing and Compliance

When deploying WDAC policies, it’s essential to monitor their processing and compliance to ensure they are being correctly applied to all targeted devices.

Solution: Use the %WINDIR%\CCM\Logs\DeviceGuardHandler.log file on managed devices to monitor the processing of WDAC policies. Additionally, check the local client event logs (Applications and Services Logs > Microsoft > Windows > Code Integrity > Operational and Applications and Services Logs > Microsoft > Windows > AppLocker > MSI and Script) to verify the specific software being blocked or audited.

By understanding and addressing these common challenges, you can effectively implement WDAC and Device Guard policies in your Windows 11 environment, providing robust security while minimizing disruptions to your users and critical business applications.

Complementing WDAC with AppLocker

While WDAC is the primary application control technology in Windows 11, there are some scenarios where AppLocker, an older application control solution, may still be a useful complement.

AppLocker allows you to control which applications are allowed to run on your Windows devices, but it doesn’t meet the security servicing criteria like WDAC does. AppLocker is best suited for scenarios where:

• You need to apply user-specific or group-specific application control rules
• You have legacy applications or workflows that may not be compatible with the stricter WDAC policies

By using AppLocker in conjunction with WDAC, you can create a more comprehensive application control strategy, leveraging the strengths of both technologies to meet your organization’s unique security and operational requirements.

For example, you can use WDAC to enforce a baseline set of application control rules at the device level, while using AppLocker to apply additional, user-specific restrictions on top of that. This approach can be particularly useful in shared device scenarios, where it’s important to prevent certain users from running specific applications.

Staying Ahead of the Curve with WDAC and Device Guard

As an experienced IT professional, it’s essential to stay up-to-date with the latest developments and best practices for implementing WDAC and Device Guard policies in your Windows 11 environment. By doing so, you can ensure that your organization’s devices are well-protected against evolving threats, while also minimizing the impact on your users and critical business applications.

To help you stay ahead of the curve, I recommend regularly checking the IT Fix blog for new articles and updates on Windows security technologies, as well as exploring the official Microsoft documentation on WDAC and Device Guard. Additionally, participating in industry forums and networking with other IT professionals can provide valuable insights and help you troubleshoot any challenges you may encounter.

Remember, the world of IT security is constantly evolving, and it’s our responsibility as seasoned professionals to continuously improve our knowledge and skills to deliver the best possible solutions for our organizations. By mastering the intricacies of WDAC and Device Guard, you’ll be well-equipped to navigate the ever-changing landscape of Windows 11 security and ensure your users and data remain protected.