Mastering Microsoft 365 security means understanding both the strengths and the boundaries of Microsoft 365 native tools and knowing why best-in-class protection requires a broader approach using third-party tools.
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Microsoft 365 offers robust native security tools, but operational and visibility gaps remain, even for well-licensed enterprises. Relying solely on built-in tools leaves organizations vulnerable. To achieve true resilience, enterprises must integrate third-party solutions like CoreView, extending security beyond Microsoft’s out-of-the-box capabilities. This blog explores Microsoft 365’s security stack, its real-world gaps, and best-practice approaches for unifying and fortifying your environment against advanced threats, insider risks, and evolving compliance demands.
For all their power, even a fully licensed Microsoft 365 E5 environment leaves enterprise security teams exposed. Forrester cautioned that relying solely on native cloud security tools is a risk, and most organizations will need to turn to external consultants and tools to close visibility and control gaps.
This means extending security beyond the out-of-the-box Microsoft 365 capabilities by integrating third-party platforms that deliver advanced security and resilience features. In other words, Microsoft 365 security means knowing where native defenses end and where non-Microsoft tools are critical for end-to-end resilience.
Microsoft 365 includes a suite of integrated security and compliance tools designed to protect identities, data, devices, and collaboration environments. For CIOs, CISOs, and CTOs, understanding these tools — and how they work together — is critical to building a cohesive security strategy.
Microsoft Defender is not one product but a security family under the Microsoft 365 Defender umbrella, with different solutions for different threat vectors. Defender is designed to protect email and collaboration tools from phishing, malware, and malicious links. Underpinned by AI, Defender protects against phishing, email compromise, ransomware and other threats by checking link and attachment safety and enforcing your anti-phishing policies.
Key features include:
Ideally, organizations will apply policies to all users, not just to executives – phishing targets everyone.
Microsoft Defender for Endpoint (MDE) is endpoint detection and response (EDR) for Windows, macOS, Linux, iOS, and Android.
Key features include:
Organizations should integrate MDE with conditional access to block high-risk devices in real time.
Microsoft Defender for Identity detects advanced identity threats in on-prem Active Directory environments.
Key features include:
Organizations should deploy sensors to all domain controllers for full coverage.
Microsoft Defender for Cloud Apps (formerly MCAS) is for discovering and securing SaaS usage.
Key features include:
Organizations should use session controls to block downloads of sensitive data from unsanctioned cloud apps.
Microsoft Secure Score is a framework designed to promote good security practices inside Microsoft 365 and a security posture measurement tool offering improvement actions you can take.
From a dashboard within Microsoft Defender, you can follow a structured process for improving your security posture, then see how you’re doing with a simple percentage score. While this provides a good at-a-glance view of your security, it is by no means exhaustive and requires a lot of manual handling.
Key features include:
Organizations should treat Secure Score as an operational KPI to review monthly and track improvements in an ongoing manner.
Microsoft Sentinel is cloud-native security information and event management (SIEM) and security orchestration, automation, and response (SOAR). It collects data from across your Microsoft 365 environment and uses it to highlight risks and potential threats. Operationalizing Sentinel often requires significant resources, custom integrations, and expertise to close the visibility and workflow gaps.
Sentinel can also be connected to your non-Microsoft software, enriching your data pool for more accurate insights into baseline usage and trends that may indicate an attack.
Key features include:
Organizations should use Microsoft-provided Sentinel workbooks for M365 security data visualization.
Microsoft Purview is a unified platform for compliance, data protection, and governance.
Key features include:
Organizations should integrate Purview with Microsoft Defender for coordinated data protection.
Entra ID Protection offers real-time identity risk detection and remediation.
Key features include:
Organizations should pair Entra ID Protection with privileged identity management (PIM) for a secure admin life cycle.
M365 Compliance Center is a centralized portal for compliance-related policies and reports.
Key features include:
Organizations can use Compliance Score in parallel with Secure Score to get a balanced overview of their security and compliance posture.
Also key, beyond Microsoft’s native security stack and how important its full configuration and deployment are to its effectiveness, is the understanding that some critical security functionality is missing from the M365 suite of tools. This should be augmented by a combination of security-by-design principles and third-party solutions that help deliver a more comprehensive and complete security posture.
Microsoft 365’s native security capabilities are not comprehensive. Even in an E5 license environment with the full suite of Microsoft Defender, Purview, Sentinel, and Entra ID Protection, there are visibility gaps, operational limitations, and automation challenges that enterprise security leaders must address.
While Microsoft Defender and Microsoft Sentinel can help detect unusual behavior and potential insider threats, the human element remains a critical vulnerability. Insider threats and human errors, such as falling for phishing scams, using weak passwords, or misconfiguring systems, can lead to security breaches that these tools might not always predict or prevent.
Security signals are spread across all of the native Microsoft security tools, which means security teams spend a lot of time pivoting between siloed system and may miss correlated threats. Resulting slower detection thresholds means that incident response is equally delayed.
APTs are sophisticated, long-term attacks by highly skilled adversaries targeting specific organizations. While Microsoft's tools are designed to detect and mitigate many forms of cyberattacks, the highly customized nature of APTs means that some attacks might bypass detection mechanisms, especially in their initial stages.
Attackers increasingly target software suppliers and other third-party vendors as a means to gain access to their primary targets. While Microsoft's security solutions offer ways to monitor and secure your environment, they may not fully cover the complexities of assessing and mitigating risks introduced by third-party vendors and software.
Native Microsoft tooling is designed to manage single-tenant architectures. Holding companies and global organizations with multiple tenants cannot easily manage policies or manage security posture centrally. Again, it becomes almost impossible to monitor and manage threats under these conditions.
Native role-based access control (RBAC) does not enable fine-grained control over granting privileges, which means that admins may have unintended access to sensitive systems or data.
Routine security tasks, such as license compliance checks, stale account cleanup, role change reviews, demand manual work or PowerShell scripts, and the tedium of these tasks exposes organizations to risk from human error as well as operational bottlenecks.
Microsoft’s native tools focus on detection and response. Proactive governance and preventive alerts require extra configuration or external tools. This can lead to a gradual erosion of Zero Trust enforcement.
A truly resilient Microsoft 365 environment demands more than configuration and compliance checklists. Best-practice security requires unified, ongoing visibility across all tenants and workloads.
This is where CoreView acts as a control plane to augment your native M365 security stack:
The comprehensive guide to M365 security best practices is a great place to start, even before you think about tooling.
CoreView brings all critical signals together—MFA status, privileged roles, guest user activity, license usage—on a single dashboard for rapid detection and executive reporting.
Native M365 falls short with complex, multi-tenant environments. CoreView enables consistent policy enforcement, cross-tenant threat monitoring, and targeted admin delegation via Virtual Tenants—reducing the risk of excessive privilege.
Eliminate manual PowerShell scripts and routine admin chores. CoreView automates privilege change alerts, cleanup of inactive users, compliance checks, and more, reducing human error and freeing up security teams’ time for higher-value work.
Enforce policies proactively and continuously, not just during audits. CoreView’s governance engine keeps your security aligned to Zero Trust principles and prevents configuration drift.
With real-time contextual insight and rapid alerting, CoreView empowers security teams to contain threats faster and respond with agility.
Microsoft 365’s built-in security tools are powerful, but stopping there means accepting operational gaps, visibility challenges, and the ongoing risk of misconfiguration and oversight. A best-practice Microsoft 365 security strategy relies on enhancing these native tools with automation, governance, cross-tenant visibility, and true least-privilege delegation.
CoreView is purpose-built to close these gaps, ensuring you don’t just react to threats but get ahead of them. Think of M365 as your security engine, and CoreView as the control system keeping it running smoothly, securely, and resiliently.
Ready to move from good enough to best-in-class Microsoft 365 security and resilience? Discover how CoreView can help.
