As organizations increasingly embrace digital transformation, electronically stored data is a company’s most valuable asset. Unfortunately, it’s also one of the most vulnerable. Whether it’s customer records, financial data, intellectual property, or sensitive internal communications, protecting this information from accidental or malicious exposure is critical. This is where Data Loss Prevention (DLP) comes in.
DLP is a proactive approach to data protection that helps prevent the unauthorized sharing, transfer, or leakage of sensitive information. With the widespread adoption of Microsoft Office 365 across organizations of all sizes, implementing robust DLP policies within the Microsoft 365 environment is no longer optional—it’s essential.
In this guide, we’ll explore what Microsoft Purview DLP is, how it works, the benefits it offers, how to set it up, and best practices to maximize your cloud security strategy. Whether you’re an IT decision-maker, administrator, or just exploring DLP solutions, this guide will provide actionable insights to improve your data security and avoid costly data breaches.
Microsoft Purview: A Broader Platform
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Before diving further into Microsoft Purview DLP, it’s helpful to understand the broader suite of capabilities that Microsoft Purview provides. Microsoft Purview is not just about data loss prevention—it’s a comprehensive platform for unified data governance, compliance, and risk management across your digital ecosystem.
In addition to DLP, Microsoft Purview includes:
- Information Protection: Helps classify, label, and encrypt sensitive data based on sensitivity labels—whether the data is stored in Microsoft 365, on devices, or in other cloud services.
- Insider Risk Management: Identifies and mitigates risky behavior by insiders, like data exfiltration or policy violations. We provide more details on this feature in a related blog post.
- Communication Compliance: Ensures internal and external communications comply with company policies and regulatory requirements.
- Records Management: Manages retention and deletion of content according to regulatory or business requirements.
- Audit and eDiscovery: Supports investigations and legal holds with comprehensive auditing and search capabilities.
All these tools work together to provide a layered, adaptable approach to information security. For example, sensitivity labels created in Microsoft Information Protection can be used to trigger DLP policies. Insider risk signals can help inform adaptive protection policies that dynamically apply stricter controls to high-risk users.
For this article, we’ll be focusing on DLP, but keep in mind that a well-rounded compliance and security strategy often involves leveraging multiple Microsoft Purview solutions in tandem along with a strong user-focused program on handling of sensitive data. Even the most advanced DLP technology can’t protect data in isolation—users must be educated and engaged participants in any data loss prevention program.
What is Microsoft Purview DLP?
Microsoft Purview DLP is a suite of tools built into the Microsoft 365 ecosystem that helps identify, monitor, and automatically protect sensitive data from leaving your organization. These tools use pre-configured rules, content inspection techniques, and user interaction cues to prevent unintentional or unauthorized data sharing.
How It Works
When a user attempts to share or move content that contains sensitive information types (like credit card numbers, Social Security numbers, or health records), Microsoft Purview DLP scans and evaluates the content based on predefined or custom rules. Based on the configured policies, it can:
- Display a policy tip to alert the user
- Block the action entirely
- Block, but allow the user to override
- Log the incident for review in a DLP alert
Note that policy tips are currently (May 2025) supported in ‘new’ Outlook, Outlook on the web (OWA) and newer Windows versions of Outlook, but not in mobile apps or classic/legacy Outlook for Mac. In Teams, tips appear for messages but not for files.
Key Components of Microsoft Purview DLP
Several essential components support Purview DLP actions.
- DLP Policy Templates – Prebuilt templates for common regulations like GDPR, HIPAA, and PCI-DSS.
- Custom DLP Policies – Tailor-made policies designed for your specific organizational needs.
- Sensitive Information Types (SITs) – Definitions that describe patterns of data to detect and protect using built-in logic. This includes matching patterns, keywords, expressions, or logic to identify documents that do not follow a common pattern. Microsoft Purview provides:
- Built-in SITs: Predefined patterns like credit card numbers.
- Custom SITs: User-defined patterns and keywords.
- Exact Data Match (EDM): Precise matching using specific uploaded datasets, such as all known employee ID numbers.
- Trainable Classifiers: Built-in and custom machine-learning models for complex data—think matching all ‘HR’ documents or something where a pattern alone is not enough to identify the document.
- Policy Tips – In-app notifications within Microsoft Office (Outlook, Word, Excel) and Microsoft Teams that guide users.
- Incident Reports and Alerting – Alerts and logs that provide visibility into DLP events.
- Integration with Microsoft 365 Services – Works across SharePoint Online, OneDrive for Business, Microsoft Teams, and Exchange Online.
- Integration with Managed Endpoints – Works to monitor and prevent exfiltration activities (transferring sensitive files to USB, printing sensitive files, copying content out of sensitive files to unapproved applications, etc.)
Benefits of Implementing Microsoft Purview DLP
Implementing Microsoft Purview DLP yields tangible benefits across multiple parts of your organization’s security and compliance posture:
1. Comprehensive Data Protection
DLP policies help secure sensitive content across emails, files, chats, and cloud storage, minimizing the risk of data loss.
2. Regulatory Compliance
Built-in policy templates help you comply with regulations like GDPR, HIPAA, and CCPA by identifying and protecting regulated data types.
3. Reduced Risk of Data Breaches
Real-time intervention, like policy tips and blocking actions, stop data leaks before they occur, helping avoid costly data breaches.
4. Real-Time Monitoring and Reporting
Detailed dashboards and DLP reports provide IT admins with visibility into policy effectiveness, potential incidents, and user behavior.
5. Enhanced Trust
Strong information protection controls build trust with customers, partners, and stakeholders by demonstrating a commitment to data protection.
Best Practices for Implementing Microsoft Purview DLP
To make the most of your Microsoft Purview DLP implementation, keep these best practices in mind:
1. Define Clear Objectives
Know what you want to achieve. Is it regulatory compliance? Want to prevent accidental sharing of financial data? Start with a goal.
2. Provide Security Awareness Training
Your users are your first line of defense. Train them to recognize and properly handle sensitive information. Reinforce behavior with policy tips.
3. Customize Policies to Fit Your Needs
Avoid relying solely on default templates. Tailor your data loss prevention policy to reflect your unique organizational workflows and risk appetite.
4. Monitor and Iterate
Use DLP reports and alerts to monitor performance effectiveness, uncover gaps, and identify false positives. Use this information to refine your rules to minimize false positives, target specific sensitive locations or high-risk users, and optimize protection.
5. Use Additional Protection Tools
While Microsoft Purview DLP covers a lot, it may not be enough on its own. Consider bolstering your strategy with:
- Microsoft Information Protection (MIP) for classification and labeling.
- Microsoft Defender for advanced threat protection and behavior analytics. We have some additional information about Microsoft Defender here.
- Endpoint DLP to monitor and restrict data activity on Windows 10/11 and macOS devices, including USB copy prevention and print blocking.
- Adaptive Protection for dynamically adjusting policy enforcement based on user risk level.
- Activity Explorer for visibility into how sensitive data is being accessed and shared.
- Data Explorer (formerly Content Explorer) for visibility into how and where sensitive data is stored across your environment.
Many of the daily operations associated with Purview can be handled through a tool that you may already be utilizing: the Microsoft 365 Defender Portal. This portal offers a unified platform for alert triage, incident management, and seamless integration with Microsoft Sentinel.
Licensing Note: Advanced features such as endpoint DLP, and trainable classifiers may require Microsoft 365 E5 or Microsoft 365 E5 Compliance licenses.
How to Set Up Microsoft Purview DLP
Microsoft frequently updates the user interface and feature set for the Microsoft Purview Compliance Portal. Rather than outlining steps here that may quickly become outdated, we recommend referring to the official Microsoft documentation for the most accurate and current guidance.
Official Microsoft Guide: Create and Deploy a DLP Policy
That said, here are some practical tips to help you implement your first policy with confidence:
- Start with a Template, then Customize: Templates help you get up and running quickly, but real protection comes from tailoring them to your organization’s data and workflows.
- Choose Coverage Areas Wisely: Target high-risk workloads first, such as Exchange Online or SharePoint Online, before expanding.
- Run in Test Mode First: Microsoft allows you to simulate policy enforcement without interrupting users. Use this to validate logic and identify false positives.
- Leverage Sensitive Labels: If you’re already using Microsoft Information Protection Labels, use them to scope or trigger your DLP policies.
- Include Users in the Loop: Enable policy tips so users receive guidance when they interact with sensitive information.
- Review Reports Early and Often: Use DLP reports and alerts to monitor effectiveness, uncover gaps, and tune policies accordingly.
Remember that you will also need to consider the balance between security and user experience. Overly aggressive policies that disrupt daily workflows can lead to user frustration, non-compliance, and attempts to circumvent controls. A successful DLP strategy ensures data protection without getting in the way of productivity.
For complex environments or organizations with compliance obligations, DLP configuration can quickly become nuanced. In those cases, consulting with experts—like the team at Ravenswood—can help you architect a solution that balances protection with productivity
Conclusion
Data loss prevention is no longer a “nice to have” —it’s a strategic necessity. With sensitive customer records, confidential business documents, and critical IP residing in the cloud, the stakes are higher than ever.
Microsoft Purview DLP provides a robust foundation for protecting that data, ensuring compliance, and avoiding an embarrassing or costly data breach. By leveraging tools like policy tips, custom DLP policies, trainable classifiers, adaptive protection, and built-in sensitive information types, your organization can take meaningful steps to mitigate risk.
Just remember: technology alone isn’t the full solution. It lays the foundation, but it’s your users who uphold the structure. Data loss prevention must be a shared responsibility—users need to be aware, engaged, and empowered to make the right decisions. Embedding user education and participation into your DLP program is just as critical as the tools enforcing the policies. Combining security awareness training, customized implementation, and layered cloud security tools is key to success.
Partner With Experts
Whether you’re just getting started or looking to enhance your current strategy, Ravenswood is here to help.
At Ravenswood Technology Group, we have hands-on experience implementing DLP in complex Microsoft 365 environments. From design to deployment to tuning, our team helps you stay secure, compliant, and productive.
We don’t just implement policies—we help organizations develop a comprehensive data protection program aligned with business objectives and regulatory requirements. Whether you’re rolling out Microsoft Purview for the first time, refining an existing policy set, migrating from another DLP toolset, or integrating with other Microsoft security tools, our consultants are equipped to guide you.
Our engagements often include readiness assessments, policy workshops, developing user training strategies, and post-deployment tuning to ensure that DLP doesn’t just work—it works for you. Let us help you turn compliance obligations into operational advantages.
Ready to protect your data? Contact us today…
