The Role of Microsoft Purview in Microsoft 365 Security Best Practices: Enabling DSPM and Preventing Oversharing at Enterprise Scale

Microsoft Purview is a comprehensive data governance and compliance solution that plays a pivotal role in enhancing Microsoft 365 security best practices.

By unifying data protection, risk management, and compliance capabilities, it empowers organizations to safeguard sensitive information, meet regulatory requirements, and maintain a robust security posture in the cloud.

Two critical areas where Microsoft Purview shines are Data Security Posture Management (DSPM) and preventing oversharing at enterprise scale. This article explores how Purview integrates into Microsoft 365 security strategies and delivers actionable controls to address these modern challenges.

What is Microsoft Purview?

Microsoft Purview combines the former Azure Purview and Microsoft 365 compliance solutions into a single platform focused on data governance, protection, and risk mitigation.

It integrates seamlessly with Microsoft 365 services—such as Exchange Online, SharePoint, OneDrive, and Teams—offering tools like sensitivity labels, Data Loss Prevention (DLP), insider risk management, and information governance. For security teams, Purview provides a centralized hub to discover, classify, protect, and monitor data across the Microsoft 365 ecosystem, hybrid environments, and even third-party applications.

In the context of security best practices, Purview acts as both a proactive and reactive layer. It helps organizations understand their data landscape (where sensitive data resides), enforce policies to protect it, and respond to threats or policy violations. This dual capability makes it indispensable for tackling DSPM and oversharing—two pressing concerns in cloud-first enterprises.

Enabling Data Security Posture Management (DSPM)

Data Security Posture Management is an emerging discipline focused on continuously assessing and improving an organization’s data security by identifying risks, misconfigurations, and vulnerabilities across data repositories. In Microsoft 365, where data sprawls across emails, documents, and collaboration platforms, maintaining visibility and control is a daunting task. Microsoft Purview addresses this through several key features:

Data Discovery and Classification:

Purview’s sensitive information types and trainable classifiers automatically scan Microsoft 365 workloads to identify sensitive data, such as personally identifiable information (PII), financial records, or intellectual property. Sensitivity labels—customizable tags like “Confidential” or “Restricted”—can then be applied manually or automatically to categorize data based on its risk level.

This visibility is the foundation of DSPM, enabling organizations to map their data estate and understand exposure risks.

Risk Assessment and Insights:

The Data Map and Content Explorer in Purview provide a unified view of where sensitive data lives and how it’s being used. For example, administrators can see if “Highly Confidential” files are stored in unsecured SharePoint sites or shared externally.

Integration with Microsoft Defender for Cloud Apps enhances this by flagging misconfigurations (e.g., overly permissive sharing settings) or anomalous behaviors (e.g., bulk downloads), offering a real-time posture assessment.

Policy Enforcement:

Purview’s Data Loss Prevention (DLP) policies allow organizations to enforce rules based on data classification. For instance, a policy might block files labeled “Sensitive” from being emailed to external domains or uploaded to unapproved cloud services.

Adaptive Protection, powered by insider risk analytics, dynamically adjusts controls based on user behavior, strengthening posture without manual intervention.

Remediation and Monitoring:

Purview provides actionable recommendations—such as tightening permissions on a SharePoint site hosting sensitive data—and tracks remediation progress. Audit logs and compliance dashboards ensure ongoing posture improvement aligns with security goals.

By combining these capabilities, Purview transforms DSPM from a theoretical concept into a practical framework. It gives security teams the tools to proactively identify vulnerabilities (e.g., unclassified sensitive data in Teams chats) and remediate them before exploitation occurs, aligning with best practices for a Zero Trust security model.

Preventing Oversharing at Enterprise Scale

Oversharing—when sensitive data is unintentionally or excessively exposed to internal or external users—is a pervasive risk in Microsoft 365, especially in collaborative environments with guest sharing and open permissions. At enterprise scale, manual oversight becomes impractical, making automated controls essential. Microsoft Purview tackles oversharing through a layered approach:

Sensitivity Labels as a Control Layer:

Sensitivity labels are Purview’s frontline defense against oversharing. Once applied, labels can restrict actions based on content sensitivity. For example, a “Highly Confidential” label might block external sharing, encrypt the file, or limit access to specific users.

Auto-labeling policies scale this protection by applying labels to existing and new content across Microsoft 365 without user intervention, ensuring consistent enforcement enterprise-wide.

• Data Loss Prevention (DLP) Policies: DLP policies in Purview monitor and block risky sharing actions in real time. For instance, if a user attempts to share a document containing credit card numbers with an external guest in Teams, Purview can prevent the action and notify the user or administrator. These policies scale across workloads—covering email, OneDrive, SharePoint, and Teams—and can be tailored to specific departments, regions, or compliance needs (e.g., GDPR, HIPAA).
• Sharing Link Restrictions: Purview integrates with Microsoft 365 sharing controls to enforce secure link settings. Administrators can mandate that shared links expire after a set period (e.g., 30 days), require authentication, or limit access to “specific people” rather than “Anyone with the link.” Sensitivity labels can override looser defaults, preventing accidental oversharing.
• Guest Access Governance: For external collaboration, Purview works with Azure AD to enforce strict guest policies. Sensitivity labels and DLP can restrict what guests see or download, while access reviews (via Azure AD) ensure guest permissions are revoked when no longer needed, reducing the risk of lingering exposure.
• Behavioral Analytics and Alerts: Purview’s insider risk management analyzes user activity to detect potential oversharing incidents, such as a user sharing multiple sensitive files with an external contact. Custom alerts and playbooks allow rapid response, while machine learning refines detection over time.

Integration with Defender for Cloud Apps adds session-level controls, like blocking downloads by guests, to halt oversharing in progress.

Enterprise-Scale Automation:

At scale, manual checks are infeasible. Purview’s automation—via auto-labeling, DLP, and risk analytics—ensures consistent protection across thousands of users and terabytes of data. Compliance scores and reports provide leadership with visibility into sharing risks and mitigation efforts.

Practical Example: Combining DSPM and Oversharing Prevention

Imagine an enterprise with 50,000 employees using Microsoft 365. Purview scans SharePoint sites and discovers unclassified contracts with PII stored in a public-facing library—a DSPM-identified risk. It auto-applies a “Confidential” label, restricting sharing to internal users only.

Simultaneously, a DLP policy prevents an employee from emailing one of these contracts to an external vendor, displaying a warning and logging the attempt. An insider risk alert flags the user’s repeated attempts, prompting a review. This integrated approach showcases how Purview aligns DSPM insights with oversharing controls to secure data at scale.

Talhah Mir, Microsoft Purview’s Principal Group Product Manager, shows how to transform your data security strategy with automated, intelligent risk management and maintain continuous protection across your organization.

Stay ahead of evolving risks and mitigate vulnerabilities with Microsoft Purview Data Security Posture Management (DSPM). Gain prioritized visibility into data security risks, track unprotected sensitive information, and receive actionable insights. With built-in classifiers, automated risk assessments, and AI-powered capabilities like Security Copilot, you can identify and mitigate threats, ensuring a compliant data security environment.

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Conclusion

Microsoft Purview is a linchpin in Microsoft 365 security best practices, bridging the gap between data visibility and actionable protection. For DSPM, it delivers the tools to discover, assess, and remediate data risks across the tenant, ensuring a proactive security posture. For oversharing prevention, it scales enforcement through automation, labels, and policies, curbing exposure without stifling collaboration.

By embedding Purview into your security strategy, you can transform Microsoft 365 from a sprawling data ecosystem into a controlled, compliant environment—ready to meet the demands of enterprise-scale security in a cloud-first world. Start with a data discovery scan today, and let Purview guide your path to a stronger, safer tenant.

Minimize risks that come with oversharing and potential data loss. Use Microsoft Purview and its new Data Security Posture Management (DSPM) for AI insights, along with new Data Loss Prevention policies for Microsoft 365 Copilot, and SharePoint Advanced Management, which is now included with Microsoft 365 Copilot. Automate site access reviews at scale and add controls to restrict access to sites if they contain highly sensitive information.

Erica Toelle, Microsoft Purview Senior PM, shows how to control data visibility, automate site access reviews, and fine-tune permissions with Pilot, Deploy, Optimize phases.