Microsoft Defender for Microsoft 365 – the evolution of Microsoft 365 Advanced Threat Protection (ATP) – is frequently cited as a robust solution aimed at defending organizations against a broad spectrum of cybersecurity threats. It offers a range of capabilities, including:

• Scanning email attachments for malware
• Analyzing URLs in emails and Microsoft 365 documents (Safe Links)
• Blocking harmful files in SharePoint, OneDrive, and Microsoft Teams (Safe Attachments)
• Checking messages for signs of email spoofing or email impersonation
• Detecting attempts to imitate users or domains via built-in anti-phishing features

A notable strength of Defender for Microsoft 365 is the ability to create granular policies for its anti-phishing, safe links, and safe attachments features. Reporting also benefits from Microsoft’s broad threat visibility. However, even with this tight integration into the Microsoft 365 environment, many businesses still find gaps and rely on third-party email security solutions, often limiting the overall effectiveness of the native tools alone. This highlights the need for layered cybersecurity.

Microsoft promotes Defender for Microsoft 365 as a significant step forward compared to Exchange Online Protection (EOP). Yet, EOP has long been criticized by some as a basic spam filter. The performance of the native tools also varies by subscription level. Although bundled features may appeal to some businesses, many find the functionality lacking when compared to dedicated tools for email phishing protection or advanced malware protection.

Limited Protection from Internal Microsoft 365 Phishing

One of Defender for Microsoft 365’s potential vulnerabilities lies in filtering phishing emails that originate within the Microsoft 365 network. Even with protections active, phishing messages sent between tenants can sometimes slip through due to implicit trust or specific configurations.

With millions of commercial users, this represents a large internal threat surface. The result is a higher likelihood of account compromise, email impersonation, and potential data breaches—leading to significant IT overhead.

Implementing additional layers such as strong email authentication (like DMARC), along with tools like OnDMARC (from providers like Red Sift), or Proofpoint Essentials, can significantly reduce exposure to these types of email phishing attacks.

No Email Continuity During Outages

While not an inherent flaw of Defender itself, Microsoft 365 lacks native support for business continuity during major service interruptions. Outages, while not constant, do occur and can disrupt business operations. Without a contingency plan, organizations can lose access to critical communications.

Third-party continuity tools, often included in bundles like Proofpoint Essentials, can help fill this gap by offering features such as email spooling and emergency inbox access. This ensures that essential email security functions remain available even during Microsoft 365 downtime.

Archiving Limitations

Although Microsoft 365 includes built-in email archiving, the native tools can sometimes be perceived as slow and may offer limited features for complex legal defensibility—particularly for industries with strict compliance requirements.

Search performance and usability can also be challenging for demanding eDiscovery needs. Organizations dealing with HIPAA compliant email or similar regulatory frameworks often turn to third-party email archiving solutions for improved reliability, security, and search capabilities.

Hidden Costs and Opportunity Loss

Defender for Microsoft 365 may appear cost-effective, but hidden expenses can add up. Whether it’s time lost managing potential gaps or the need to integrate third-party solutions, these costs can erode savings. Common needs like robust email encryption, advanced email phishing attack detection, and specialized malware protection often require tools outside of the standard Microsoft ecosystem, such as those offered by Proofpoint, to achieve full functionality and compliance.

Better Protection with Vircom

Vircom offers enhanced Microsoft 365 email security solutions powered by Proofpoint technology that significantly extend beyond Microsoft’s native protection capabilities.

These solutions provide comprehensive email threat defense through advanced phishing detection mechanisms, versatile encryption options for securing Outlook communications, and robust email archiving functionality.

Proofpoint Essentials serves as the foundation of this security ecosystem, simultaneously strengthening an organization’s security posture while improving operational efficiency. This scalable solution is particularly valuable for businesses requiring more robust protection than Microsoft’s standard security offerings.

For Managed Services Providers (MSPs) and SMBs, Vircom further simplifies Microsoft 365 email security management through its seamless integration with ConnectWise Manage. This integration streamlines critical operational processes including billing automation, mailbox monitoring, and comprehensive cybersecurity management, creating a more unified and efficient security administration experience.

Faster, Simpler Deployment for Microsoft 365 Clients

One challenge MSPs face deploying third-party email security is the complexity of changing MX records and configuring mail flow.

Addressing this, Proofpoint recently announced the availability (April 2025) of a major update to Proofpoint Essentials: the new Integrated Deployment for Microsoft 365. This method removes the need to reroute email traffic or manually set up connectors. Instead, setup uses API integration for automatic configuration of Microsoft 365 rules and Proofpoint Essentials’ policies, often in just a few clicks.

This means MSPs can protect clients faster—without the friction that typically delays onboarding.

Greater Flexibility, Same Industry-Leading Protection

With Integrated Deployment, now available as of April 2025, email flows directly into Microsoft 365 and is then processed by Proofpoint Essentials for advanced filtering without interrupting mail delivery.

This new API-based option coexists with traditional SEG (MX-based) deployments, giving MSPs the flexibility to choose the best approach for each client. Whether onboarding a small business or scaling support, the integrated approach simplifies deployments while maintaining the robust email protection Proofpoint is known for a major step forward for MSPs looking to save time and improve efficiency.

Become a partner today and start safeguarding your Microsoft 365 environment with confidence.