| 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.
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| 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"] |
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).
Common Misconfigurations & Verification
- Egress channel gaps: a policy that blocks USB and email but ignores other exits leaks data anyway. Confirm every endpoint activity is in scope — cloud upload, removable media, network share copy, print, clipboard, screen capture, paste to unallowed browser/app, and Remote Desktop copy. Unmanaged browsers (anything not in the allowed-browser list) commonly bypass web upload inspection.
- Stuck in audit: "Test mode with notifications" never blocks. In Activity Explorer the action shows
Audit, not Block/BlockWithOverride — verify the policy is actually turned on and enforced after tuning.
- Encrypted/archive blind spots: content inspection can't read password-protected ZIPs, nested archives, or images without OCR. Define how those are handled (block-on-unscannable vs. allow) rather than letting them sail through.
- Over-broad overrides: if BlockWithOverride is on with no justification logging, users self-approve every block. Check the override rate in Activity Explorer.
- Verification: from a test endpoint, attempt each channel with a seeded file (e.g., a doc containing 5+ test credit-card numbers): copy to USB, upload to personal OneDrive/Dropbox, paste into webmail, and print. Each must produce a block/audit event in Activity Explorer with the matched SIT — silent success on any channel is a coverage gap.
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"
