Create a DLP policy to protect documents with FCI or other properties

Article
02/17/2023

Microsoft Purview Data Loss Prevention (DLP) policies can use classification properties or item properties to identify sensitive items. For example you can use:

Windows Server File Classification infrastructure (FCI) properties
SharePoint document properties
third-party system document properties

Diagram showing Office 365 and external classification system.

For example, your organization might use Windows Server FCI to identify items with personal data such as social security numbers, and then classify the document by setting the Personally Identifiable Information property to High, Moderate, Low, Public, or Not PII based on the type and number of occurrences of personal data found in the document.

In Microsoft 365, you can create a DLP policy that identifies documents that have that property set to specific values, such as High and Medium, and then takes an action such as blocking access to those files. The same policy can have another rule that takes a different action if the property is set to Low, such as sending an email notification. In this way, DLP integrates with Windows Server FCI and can help protect Office documents uploaded or shared to Microsoft 365 from Windows Server-based file servers.

A DLP policy simply looks for a specific property name/value pair. Any document property can be used, as long as the property has a corresponding managed property for SharePoint search. For example, a SharePoint site collection might use a content type named Trip Report with a required field named Customer. Whenever a person creates a trip report, they must enter the customer name. This property name/value pair can also be used in a DLP policy—for example, if you want a rule that blocks access to the document for guests when the Customer field contains Contoso.

If you want to apply your DLP policy to content with specific Microsoft 365 labels, you should not follow the steps here. Instead, refer to lCreate and Deploy data loss prevention policies.

Tip

If you're not an E5 customer, use the 90-day Microsoft Purview solutions trial to explore how additional Purview capabilities can help your organization manage data security and compliance needs. Start now at the Microsoft Purview compliance portal trials hub. Learn details about signing up and trial terms.

Before you create the DLP policy

Before you can use a Windows Server FCI property or other property in a DLP policy, you need to create a managed property in the SharePoint admin center. Here's why.

In SharePoint Online and OneDrive for Business, the search index is built up by crawling the content on your sites. The crawler picks up content and metadata from the documents in the form of crawled properties. The search schema helps the crawler decide what content and metadata to pick up. Examples of metadata are the author and the title of a document. However, to get the content and metadata from the documents into the search index, the crawled properties must be mapped to managed properties. Only managed properties are kept in the index. For example, a crawled property related to author is mapped to a managed property related to author.

Note

Be sure to use a managed property name and not a crawled property name when creating DLP rules using the ContentPropertyContainsWords condition.

This is important because DLP uses the search crawler to identify and classify sensitive information on your sites, and then store that sensitive information in a secure portion of the search index. When you upload a document to Office 365, SharePoint automatically creates crawled properties based on the document properties. But to use an FCI or other property in a DLP policy, that crawled property needs to be mapped to a managed property so that content with that property is kept in the index.

For more information on search and managed properties, see Manage the search schema in SharePoint Online.

Step 1: Upload a document with the needed property to Office 365

You first need to upload a document with the property that you want to reference in your DLP policy. Microsoft 365 will detect the property and automatically create a crawled property from it. In the next step, you'll create a managed property, and then map the managed property to this crawled property.

Step 2: Create a managed property

Sign in to the Microsoft 365 admin center.
In the left navigation, choose Admin centers > SharePoint. You're now in the SharePoint admin center.
In the left navigation, choose search > on the search administration page > Manage Search Schema.
On the Managed Properties page > New Managed Property.
Enter a name and description for the property. This name is what will appear in your DLP policies.
For Type, choose Text.
Under Main characteristics, select Queryable and Retrievable.
Under Mappings to crawled properties > Add a mapping.
In the crawled property selection dialog box > find and select the crawled property that corresponds to the Windows Server FCI property or other property that you will use in your DLP policy > OK.
At the bottom of the page > OK.

Create a DLP policy that uses an FCI property or other property

In this example, an organization is using FCI on its Windows Server-based file servers; specifically, they're using the FCI classification property named Personally Identifiable Information with possible values of High, Moderate, Low, Public, and Not PII. Now they want to use their existing FCI classification in their DLP policies in Office 365.

First, they follow the steps above to create a managed property in SharePoint Online, which maps to the crawled property created automatically from the FCI property.

Next, they create a DLP policy with two rules that both use the condition Document properties contain any of these values:

FCI PII content - High, Moderate The first rule restricts access to the document if the FCI classification property Personally Identifiable Information equals High or Moderate and the document is shared with people outside the organization.
FCI PII content - Low The second rule sends a notification to the document owner if the FCI classification property Personally Identifiable Information equals Low and the document is shared with people outside the organization.

Create the DLP policy by using Security & Compliance PowerShell

The condition Document properties contain any of these values is temporarily not available in the Microsoft Purview compliance portal, but you can still use this condition in Security & Compliance PowerShell. You can use the New\Set\Get-DlpCompliancePolicy cmdlets to work with a DLP policy, and use the New\Set\Get-DlpComplianceRule cmdlets with the ContentPropertyContainsWords parameter to add the condition Document properties contain any of these values.

Connect to the Security & Compliance PowerShell

Create the policy by using New-DlpCompliancePolicy.

This PowerShell creates a DLP policy that applies to all locations.

New-DlpCompliancePolicy -Name FCI_PII_policy -ExchangeLocation All -SharePointLocation All -OneDriveLocation All -Mode Enable

Create the two rules described above by using New-DlpComplianceRule, where one rule is for the Low value, and another rule is for the High and Moderate values.

Here is a PowerShell example that creates these two rules. The property name/value pairs are enclosed in quotation marks, and a property name may specify multiple values separated by commas with no spaces, like "<Property1>:<Value1>,<Value2>","<Property2>:<Value3>,<Value4>"....
```
New-DlpComplianceRule -Name FCI_PII_content-High,Moderate -Policy FCI_PII_policy -AccessScope NotInOrganization -BlockAccess $true -ContentPropertyContainsWords "Personally Identifiable Information:High,Moderate" -Disabled $falseNew-DlpComplianceRule -Name FCI_PII_content-Low -Policy FCI_PII_policy -AccessScope NotInOrganization -BlockAccess $false -ContentPropertyContainsWords "Personally Identifiable Information:Low" -Disabled $false -NotifyUser Owner
```
Windows Server FCI includes many built-in properties, including Personally Identifiable Information used in this example. The possible values for each property can be different for every organization. The High, Moderate, and Low values used here are only an example. For your organization, you can view the Windows Server FCI classification properties with their possible values in the file Server Resource Manager on the Windows Server-based file server. For more information, see Create a classification property.

When you finish, your policy should have two new rules that both use the Document properties contain any of these values condition. This condition won't appear in the UI, though the other conditions, actions, and settings will appear.

One rule blocks access to content where the Personally Identifiable Information property equals High or Moderate. A second rule sends a notification about content where the Personally Identifiable Information property equals Low.

New DLP policy dialog showing two rules just created.

After you create the DLP policy

Doing the steps in the previous sections will create a DLP policy that will quickly detect content with that property, but only if that content is newly uploaded (so that the content's indexed), or if that content is old but just edited (so that the content's re-indexed).

To detect content with that property everywhere, you may want to manually request that your library, site, or site collection be re-indexed, so that the DLP policy is aware of all the content with that property. In SharePoint Online, content is automatically crawled when content is edited. Specific SharePoint sites can't be manually re-indexed.

Caution

Re-indexing a site for DLP scenarios is not possible.

For more information, see Manually request crawling and re-indexing of a site, a library or a list.

Reindex a site (optional)

On the site, choose Settings (gear icon in upper right) > Site Settings.
Under Search, choose Search and offline availability > Reindex site.