Optimizing Microsoft Defender for Endpoint for Comprehensive Security

In today’s rapidly evolving cybersecurity landscape, organizations of all sizes face an ever-increasing array of threats – from ransomware and data breaches to advanced persistent threats and zero-day attacks. As the largest market share leader for endpoint security, Microsoft has stepped up to the challenge with its robust and comprehensive Microsoft Defender for Endpoint (MDE) solution.

MDE offers a foundational set of industry-leading prevention and protection capabilities, helping organizations rapidly stop attacks, scale their security resources, and evolve their defenses. However, to truly unleash the full potential of this powerful tool, it’s essential to optimize its configuration and leverage its advanced features.

Mastering Mixed Licensing Scenarios

One of the key capabilities introduced by Microsoft is the ability to manage mixed licensing scenarios across your organization. This allows you to deploy different Defender for Endpoint licenses (Plan 1 and Plan 2) on different devices, depending on their specific security requirements and risk profiles.

To get started, you’ll need to have active trial or paid licenses for both Defender for Endpoint Plan 1 and Plan 2, or Microsoft Defender for Server Plan 1/Plan 2. Additionally, you’ll need one of the following roles assigned in Azure Active Directory: Global Admin, Security Admin, License Admin, or MDE Admin.

Once you’ve met these prerequisites, you can follow these steps to enable mixed mode and validate license assignment at scale using dynamic tagging:

1. Sign in to the Microsoft 365 Defender portal and navigate to Settings > Endpoints > License.
2. Select the Manage subscription settings option and choose the Dynamic rule option.
3. Specify one or more criteria for client endpoints to tag those devices with the “License MDE P1” using Dynamic tagging.
4. Save your rule and wait for up to 3 hours for the updated tagging and usage report to reflect the changes.

By leveraging this mixed licensing capability, you can optimize your licensing usage, ensure compliance, and provide the appropriate level of security for each device in your environment, all while saving on costs.

Streamlining Scheduled Antivirus Scans

In addition to the always-on, real-time protection provided by MDE, you can also configure regular, scheduled antivirus scans on your devices. These scheduled scans can help identify and remediate any potential threats that may have evaded the real-time defenses.

Microsoft recommends configuring a combination of quick scans and full scans to strike the right balance between performance and comprehensive protection. Quick scans are designed to quickly scan the most critical areas of your system, while full scans perform a sequential file scan of all fixed and removable network drives.

When setting up your scan schedule, consider the following best practices:

• Leverage quick scans: Quick scans are typically faster and less resource-intensive, making them a great option for regular, scheduled scans. They can be configured to run at a frequency that suits your organization’s needs, such as daily or weekly.
• Schedule full scans strategically: Reserve full scans for less frequent, periodic runs (e.g., monthly or quarterly) to ensure comprehensive coverage of your system without significantly impacting device performance.
• Optimize scan timing: Schedule scans during off-peak hours or when devices are idle to minimize disruption to users and critical business operations.
• Consider device performance: Adjust the CPU usage limit (also known as CPU throttling) based on the resources available on each device. This can help balance protection efficacy and system responsiveness.
• Exclude trusted content: Leverage the built-in optimizations in MDE to skip scanning highly reputable content, such as files signed by trusted sources, to improve scan performance.

By fine-tuning your scheduled scan configuration, you can ensure that your devices are thoroughly protected without compromising on overall system performance.

Leveraging Custom Indicators of Compromise (IoCs)

One of the powerful features of MDE is its support for custom Indicators of Compromise (IoCs). These custom IoCs allow your security operations team to fine-tune detections based on your organization’s specific threat intelligence and security requirements.

When implementing custom IoCs, keep the following best practices in mind:

1. Use ‘allow IoC’ sparingly: Each ‘allow IoC’ policy can open up new attack vectors and increase the overall IoC count. Limit the use of these policies to only essential exclusions.
2. Set expiration dates for imported indicators: When ingesting third-party threat intelligence feeds, set an expiration date for the imported indicators to ensure that your security coverage remains up-to-date and relevant.
3. Identify and remove duplicate indicators: Regularly review your custom IoCs to identify and remove any duplicate indicators that may be consuming your tenant’s 15,000-indicator limit without providing additional protection.
4. Periodically clean up old indicators: As part of your regular review process, remove any custom IoCs that are no longer relevant or necessary for your organization’s security posture.

By optimizing your custom IoC implementation, you can ensure that your organization’s unique security requirements are effectively addressed without introducing unnecessary complexity or resource constraints.

Enhancing Scan Performance and Efficiency

While the default configuration of MDE’s real-time protection, quick scans, and cloud-delivered protection provides a strong baseline of security, there may be scenarios where you need to run more resource-intensive full scans. In these cases, it’s important to understand the factors that can impact scan performance and take steps to optimize the process.

Some key considerations and best practices for improving full scan performance include:

1. Leverage scan exclusions: Carefully develop file and folder exclusions to reduce scan time without compromising risk. Avoid excluding user-scoped temporary folders or compressed files if allowed by your compliance requirements.
2. Optimize container/archive scanning: Extracting the contents of containers and archives can enable parallel scanning and improve overall efficiency.
3. Manage CPU throttling: Use the CPU usage limit setting to balance scan performance and system responsiveness, adjusting the value based on the specific requirements of your environment.
4. Leverage built-in optimizations: Take advantage of MDE’s ability to skip scanning highly reputable content, such as files signed by trusted sources, to improve scan speed.
5. Configure scan policies by device type: Tailor your scan policies to the specific requirements of different device groups, such as SQL servers, IIS servers, and workstations.

By implementing these optimization techniques, you can ensure that your full scans are performed as efficiently as possible, minimizing the impact on system resources and end-user productivity.

Integrating with Other Security Solutions

While MDE provides a robust and comprehensive security solution, it’s often beneficial to integrate it with other security tools and platforms in your organization. This can help enhance your overall security posture and leverage the strengths of different solutions.

One example of such integration is the use of application control capabilities, such as those included in Windows 10 or its predecessor, AppLocker. These tools can provide an additional layer of protection by restricting the execution of applications based on allow or block lists. By understanding how MDE’s custom IoCs interact with these application control solutions, you can identify and remove any potential duplications, further optimizing your security configuration.

Another area of integration is the use of ICAP (Internet Content Adaptation Protocol) scanning with the Microsoft Defender Antivirus engine. This can be particularly useful for organizations with Network-Attached Storage (NAS) or Storage Area Network (SAN) environments, allowing them to leverage the powerful scanning capabilities of MDE for their hybrid infrastructure.

By exploring and implementing these types of integrations, you can maximize the effectiveness of your security investments and ensure a comprehensive, layered approach to protecting your organization’s critical assets.

Conclusion

As the cybersecurity landscape continues to evolve, organizations must stay vigilant and proactive in their approach to endpoint security. By optimizing Microsoft Defender for Endpoint, you can unlock the full potential of this powerful solution and provide your users and devices with the comprehensive protection they need.

From mastering mixed licensing scenarios and streamlining scheduled antivirus scans to leveraging custom IoCs and enhancing scan performance, the strategies outlined in this article can help you create a robust and resilient security posture. Remember, the key to success is a continuous process of optimization, adaptation, and vigilance – ensuring that your security measures keep pace with the ever-changing threat landscape.

If you’re interested in learning more about Microsoft Defender for Endpoint or exploring other IT solutions, be sure to check out the resources available on IT Fix. Our team of experts is always here to provide practical advice, real-world examples, and personalized guidance to help you navigate the complex world of technology and cybersecurity.