10 Windows Defender GPO Best Practices

Windows Defender is a security feature that is built into the Windows operating system. It helps protect your computer from malware and other threats.

You can use Group Policy Objects (GPOs) to configure Windows Defender settings for your organization. In this article, we will discuss 10 best practices for using GPOs to configure Windows Defender settings.

1. Disable Windows Defender Antivirus

Windows Defender Antivirus is a security feature that’s built into Windows 10. It’s designed to protect your PC from malware, and it does a pretty good job at it. However, it can also cause some performance issues, so it’s best to disable it if you’re using another antivirus program.

Plus, if you’re using Group Policy to manage your Windows PCs, you can use a GPO to disable Windows Defender Antivirus on all of your PCs at once. This is much easier than having to go to each PC and disable it individually.

To disable Windows Defender Antivirus with a GPO, you’ll need to edit the Group Policy settings for your domain. Then, go to Computer Configuration > Policies > Administrative Templates > Windows Components > Windows Defender Antivirus.

Double-click on the Turn off Windows Defender Antivirus policy, select Enabled, and click OK.

Now, when you push out the GPO to your PCs, Windows Defender Antivirus will be disabled.

2. Enable Real-Time Protection

Real-Time Protection is a feature that monitors your system in real-time for any malicious activity and blocks it immediately. This is important because many malware programs are designed to start as soon as your system boots up, before you have a chance to run a scan and detect them.

Enabling Real-Time Protection will help ensure that these malware programs are blocked before they can do any damage.

3. Configure Exclusions for File Types, Folders, and Processes

When you exclude a file type, folder, or process from scanning, you’re essentially telling Windows Defender not to waste time scanning those items because they’re not going to be malicious. This can help improve scan times and performance, especially on systems with large numbers of files.

It’s also important to note that excluding items from scanning does not make them immune to malware. It just means that Windows Defender will not scan those items for malware. So if something does manage to get past your other defenses, it could still infect those excluded items.

That’s why it’s important to only exclude items that you know are safe. For example, you might want to exclude system files or common software programs that are known to be safe. But you wouldn’t want to exclude an entire folder like “C:\Program Files” because that could contain both safe and unsafe files.

To configure exclusions in Windows Defender GPO, go to the “Exclusions” tab and click the “Add Item” button. From there, you can add file types, folders, and processes to be excluded from scanning.

4. Configure Cloud Protection Settings

The Cloud Protection Settings in Windows Defender allow you to send information about files and apps that are unknown to Microsoft to their cloud-based services for analysis. This helps to protect your devices against the latest threats, as Microsoft can quickly develop signatures for new malware and push them out to all Defender-enabled devices.

To configure Cloud Protection Settings, open the Windows Defender Security Center and click on the “Settings” button. On the next page, scroll down to the “Cloud protection” section and turn on all three options:

– Send file samples when further review is needed
– Automatically send additional file information when needed
– Use real-time protection to scan downloaded files and programs before they run

5. Configure Network Inspection System (NIS)

NIS is a signature-less technology that uses machine learning and behavioral analysis to detect malicious traffic. It’s designed to protect against zero-day attacks, which are attacks that exploit vulnerabilities for which there is no patch available.

NIS is not enabled by default, so you’ll need to configure it using GPO. Once you’ve done so, NIS will provide an extra layer of protection for your network.

6. Configure Exploit Guard Attack Surface Reduction Rules

Attack Surface Reduction Rules help to protect against various types of attacks by reducing the attack surface of the operating system. They work by blocking certain types of malicious or suspicious activities, such as script-based attacks and email-based attacks.

Configuring these rules can be a bit tricky, but it’s well worth the effort. Not only will it help to improve your security posture, but it will also make it easier to troubleshoot issues that may arise.

When configuring Attack Surface Reduction Rules, be sure to test them thoroughly before implementing them in your production environment.

7. Configure Controlled Folder Access

Controlled Folder Access is a feature that was introduced in Windows 10 Fall Creators Update (1709) and allows you to whitelist applications that can access protected folders. This helps to prevent malicious programs from modifying files in these folders, which can lead to data loss or corruption.

To configure Controlled Folder Access, go to the Start menu and search for “Windows Defender Security Center”. Open it and click on “Virus & threat protection”. Under “Ransomware protection”, click on “Manage settings”.

Turn on Controlled folder access and click on “Protected folders”. Add the folders that you want to protect and click on “Add”.

You can also add apps to the whitelist by clicking on “Allow an app through Controlled folder access”. Click on “Add an allowed app” and browse for the application that you want to allow.

8. Configure Tamper Protection

Tamper Protection is a security feature that was introduced in Windows 10 1903 and allows you to prevent malicious changes from being made to your Defender settings. This is important because it means that even if an attacker gains access to your system, they will not be able to disable Defender or make other changes that would allow them to bypass detection.

To configure Tamper Protection, you need to create a new GPO and link it to the appropriate OU. Then, edit the following setting:

Computer Configuration > Administrative Templates > Windows Components > Windows Defender Antivirus > Turn on Tamper Protection

Set this to “Enabled” and then click “OK”.

This will ensure that Defender is always running and cannot be tampered with by attackers.

9. Configure SmartScreen Filter

The SmartScreen Filter is a security feature that was introduced in Windows 8 and is designed to help protect users from phishing attacks and malware. The filter works by checking websites against a list of known malicious sites, and if the site is on the list, the user will be warned before they visit it.

The SmartScreen Filter can be configured via Group Policy, and there are three different settings that can be applied:

– Disabled: The SmartScreen Filter is turned off and will not warn users about any sites.
– Warn: The SmartScreen Filter is turned on and will warn users about known malicious sites.
– Block: The SmartScreen Filter is turned on and will block users from visiting known malicious sites.

It’s important to note that the Block setting should only be used in high-security environments, as it can prevent users from accessing legitimate sites that have been mistakenly flagged as malicious. In most cases, the Warn setting will be sufficient to protect users without causing any major disruptions.

10. Configure Application Guard

Application Guard is a security feature that isolates untrusted applications in a separate container, so if an attacker does manage to exploit a vulnerability, they’ll be contained and prevented from doing any further damage.

To configure Application Guard, you need to create a new GPO and then edit the following settings:

– Turn on Application Guard
– Configure trusted sites
– Configure untrusted sites

Once you’ve done this, you can then apply the GPO to the appropriate OU and test it to make sure it’s working as expected.