what is DLP in m365? how you can apply it for SharePoint online with an example by using powershell commands

 Microsoft 365 Data Loss Prevention (DLP) is a security feature designed to identify, monitor, and protect sensitive information across Microsoft 365 services like SharePoint Online, OneDrive, Exchange, and Teams. It helps prevent accidental or malicious sharing, leakage, or loss of sensitive data such as personally identifiable information (PII), financial data, or health records by enforcing policies that detect sensitive content and optionally block or restrict its access or sharing.fidelissecurity+2​

How DLP Works in M365

• It uses predefined or custom sensitive information types to scan content in real-time.
• When sensitive data is detected, DLP policies can automatically trigger protective actions like blocking sharing, encrypting content, or alerting admins.
• DLP provides reporting and alerts to help manage compliance.

Applying DLP to SharePoint Online using PowerShell

To apply DLP policies to SharePoint Online, you typically create and manage the policies in Microsoft Purview compliance portal, but you can use PowerShell to assign existing DLP policies to SharePoint sites.

Here is an example approach using PowerShell with Exchange Online Management Shell and SharePoint Online:

Step 1: Connect to Exchange Online (required for DLP cmdlets)

powershell

Import-Module ExchangeOnlineManagement

Connect-ExchangeOnline -UserPrincipalName admin@yourdomain.com

Step 2: Get list of DLP policies

powershell

Get-DlpPolicy

Step 3: If you need, create a new custom DLP policy (requires detailed rules normally created via Compliance portal)

Step 4: Apply a DLP policy to SharePoint Online locations

You can assign locations for DLP policies like SharePoint sites:

powershell

Set-DlpComplianceRule -Identity "YourDLPComplianceRuleName" -SharePointSites @("https://yourtenant.sharepoint.com/sites/yoursite")

Note: Most DLP policies are managed through the Microsoft Purview compliance center GUI for policy creation and assignment. PowerShell is mainly used for policy management or automation like enabling/disabling policies or updating locations.

Summary

• DLP in M365 protects sensitive data from leakage by enforcing policies across SharePoint and other services.
• PowerShell cmdlets like Get-DlpPolicy and Set-DlpComplianceRule can manage and assign DLP policies programmatically.
• Creating and customizing DLP rules is generally done via the Microsoft Purview compliance center for granular control.

This setup ensures sensitive data stored in SharePoint Online is monitored and protected according to your organization's compliance and data governance needs.

xamples of SharePoint Data Loss Prevention (DLP) policy rules to block sensitive file sharing typically involve these components:

Example DLP Policy Use Case

• Goal: Block sharing of sensitive items (e.g., Social Security Numbers, credit card data, or documents labeled "Confidential") from SharePoint and OneDrive sites to external users.
• Exceptions: Do not block sharing for members of HR or specific internal groups.
• Actions: Block or restrict access, send alerts to security teams, notify users when sharing is blocked.

Elements of a Typical SharePoint DLP Policy Rule

Description	Configuration in DLP Rule
Users to monitor	All users, except excluded groups (e.g., Human Resources)
Locations to monitor	SharePoint sites and OneDrive accounts
Sensitive content types	US Social Security Number (SSN), Credit Card Number, Custom sensitivity labels like "Confidential"
Condition 1	Content is shared with people outside the organization
Condition 2	Content contains specified sensitive info types or sensitivity labels
Actions	Block external sharing or restrict access; notify security team via email alerts
User notification	Provide policy tips and email alerts informing users of sharing restrictions

Scenario Summary

• When a file containing sensitive data is shared externally, the DLP policy detects the content based on sensitive information types and the sharing scope.
• The policy blocks external access to that file.
• The user attempting to share receives an alert notification.
• The security or compliance team is notified by email of the incident for investigation.
• This prevents sensitive data from being leaked outside the organization via SharePoint Online.

How to Customize

• Add multiple conditions joined by AND/OR for granular control.
• Use sensitivity labels as content conditions for better integration.
• Configure incident reports and notifications.
• Define exceptions carefully to avoid business disruption.

This example is from Microsoft's official guidance on how DLP policies monitor SharePoint/OneDrive content for sensitive data and block unauthorized sharing, with alerting for compliance monitoring and user education.

 

Specific sensitive information types (SITs) you should include in your Data Loss Prevention (DLP) rules for SharePoint Online depend on your organization's compliance needs and data risks, but typically include the following categories:

Common Sensitive Info Types for DLP Policies

• Personally Identifiable Information (PII):
• Social Security Numbers (SSN)
• Passport numbers
• Driver's license numbers
• Personal addresses, phone numbers, email addresses
• Financial Information:
• Credit card and debit card numbers
• Bank account numbers
• Payment card industry data
• Health Information (Protected Health Information - PHI):
• Medical record numbers
• Health insurance information
• Genetic or biometric data
• Government Identifiers:
• Tax Identification Numbers
• National ID numbers
• Passport and visa numbers
• Authentication Data:
• Passwords
• Account credentials
• Confidential Business Data:
• Intellectual property including trade secrets, patents
• Customer data and contracts
• Financial forecasts and business strategies
• Special Categories Under Regulations (e.g., GDPR Special Category Data):
• Racial or ethnic origin
• Political opinions
• Religious or philosophical beliefs
• Genetic data and biometric data for ID purposes
• Data about sexual orientation or sex life

Why Include These?

These data types are frequently targeted for theft or accidental exposure and have legal and regulatory protections that require you to monitor and prevent unauthorized sharing or leakage.

How to Use in DLP

• Use built-in Microsoft 365 sensitive info types for easy policy creation.
• Customize and combine multiple info types in rules tailored to your organization's specifics.
• Include classification labels or tags as additional conditions.

These sensitive info types align with Microsoft Purview's built-in classifiers designed to detect and protect such information in your SharePoint Online environment.