implementing-endpoint-dlp-controls

name	implementing-endpoint-dlp-controls
description	Implements endpoint Data Loss Prevention (DLP) controls to detect and prevent sensitive data exfiltration through email, USB, cloud storage, and printing. Use when deploying DLP agents, creating content inspection policies, or preventing unauthorized data movement from endpoints. Activates for requests involving DLP, data exfiltration prevention, content inspection, or sensitive data protection on endpoints.
domain	cybersecurity
subdomain	endpoint-security
tags	["endpoint","DLP","data-loss-prevention","data-protection","content-inspection"]
version	1.0.0
author	mahipal
license	Apache-2.0
atlas_techniques	["AML.T0024","AML.T0056"]
nist_ai_rmf	["GOVERN-1.1","MEASURE-2.7","MANAGE-3.1","MAP-5.1","MANAGE-2.4"]
nist_csf	["PR.PS-01","PR.PS-02","DE.CM-01","PR.IR-01"]
mitre_attack	["T1055","T1547","T1059","T1036","T1048"]

Implementing Endpoint DLP Controls

When to Use

Use this skill when:

• Deploying endpoint DLP to prevent sensitive data (PII, PHI, PCI) from leaving the organization
• Configuring content inspection rules for email attachments, USB transfers, and cloud uploads
• Implementing Microsoft Purview DLP or Symantec DLP endpoint policies
• Meeting compliance requirements for data protection (GDPR, HIPAA, PCI DSS)

Do not use for network DLP (inline proxy-based) or cloud-only DLP (CASB).

Prerequisites

• Microsoft 365 E5 or standalone Microsoft Purview DLP license
• Microsoft Purview compliance portal access (compliance.microsoft.com)
• Sensitive Information Types (SITs) defined for organization data
• Endpoint onboarded to Microsoft Purview (via Intune or SCCM)

Workflow

Step 1: Define Sensitive Information Types

Microsoft Purview → Data Classification → Sensitive info types

Built-in SITs for common data:
- Credit card number (PCI)
- Social Security Number (PII)
- Health records (HIPAA)
- Passport number
- Bank account number

Custom SIT example (Employee ID):
  Pattern: EMP-[0-9]{6}
  Confidence: High
  Keywords: "employee id", "emp id", "staff number"

Step 2: Create DLP Policy

Microsoft Purview → Data loss prevention → Policies → Create policy

Policy Configuration:
1. Template: Financial / Medical / PII (or custom)
2. Locations: Devices (endpoint DLP)
3. Conditions:
   - Content contains: Credit card numbers (min 5 instances)
   - OR Content contains: SSN (min 1 instance)
4. Actions:
   - Block: Prevent copy to USB, cloud, email
   - Audit: Log but allow (for initial deployment)
   - Notify: Show user notification with policy tip
5. User notifications:
   - "This file contains sensitive data and cannot be copied to this location"
   - Allow override with business justification (optional)

Step 3: Configure Endpoint DLP Activities

Monitored endpoint activities:
- Upload to cloud service (OneDrive, Dropbox, Google Drive)
- Copy to removable media (USB drives)
- Copy to network share
- Print document
- Copy to clipboard
- Access by unallowed browser (non-managed browser)
- Access by unallowed app
- Copy to Remote Desktop session

For each activity, configure:
- Audit only (log the action)
- Block with override (user can justify and proceed)
- Block (prevent action entirely)

Step 4: Deploy in Audit Mode

Deploy DLP policy in "Test mode with notifications" first:
1. Policy runs in audit mode for 2-4 weeks
2. Review DLP alerts in Activity Explorer
3. Identify false positives
4. Tune SIT patterns and conditions
5. Add exclusions for legitimate workflows
6. Switch to "Turn on the policy" (enforcement)