Document Classification & Data Loss Prevention

Understand how to categorise information assets, govern subjects and objects, and apply DLP controls across military and civilian domains.

Why Classification Matters

Information classification is the decision framework that tells subjects (people, services, automated agents) how to handle objects (documents, emails, datasets, media). Proper classification drives downstream controls: least-privilege access, encryption strength, retention policies, and Data Loss Prevention (DLP) actions.

Protect crown-jewel assets such as intellectual property or national security material.
Meet compliance mandates (GDPR, HIPAA, CJIS, MOD JSP 440) and prove due diligence.
Enable business collaboration by defining what can move, where, and under which safeguards.

Subjects vs Objects

Clarify who wants to do what with which data element.

Subject: Security Operations Analyst

Object: Incident response runbook (Confidential – Internal)

Policy: Read/execute allowed, modifications require change-control approval.

Subject: Finance Data Warehouse ETL Job

Object: Quarterly earnings dataset (Restricted)

Policy: Automated process allowed to write; downstream analytics workspace blocked by DLP until CFO approval.

Subject: External Vendor Support Account

Object: Customer PII export (Highly Confidential)

Policy: Access denied; download attempt triggers DLP alert and incident response workflow.

Map every access rule to classification metadata so that enforcement (IAM, DLP, DRM) becomes automated, auditable, and scalable.

Military & National Security Model

Classification	Access Guidance	Example Objects
Top Secret	Grave damage to national security if disclosed	Nuclear launch protocols Special operations plans
Secret	Serious damage to national security	Military logistics schedules Cryptographic system designs
Confidential	Damage to national security	Force readiness reports Export-controlled technical data
Unclassified / Controlled Unclassified Information (CUI)	Not for public release but no national security penalty	Training manuals Personnel rosters

Access is governed by clearance level and a validated need-to-know. Distribution statements and caveats (e.g., NOFORN, UK Eyes Only) further restrict dissemination.

Commercial / Civilian Model

Classification	Who Can Access?	Example Assets
Public	Freely shareable information	Press releases Marketing brochures
Internal	Employees and trusted partners	Process guides Internal announcements
Confidential	Restricted to business units / need-to-know	Customer lists Financial projections
Restricted / Highly Confidential	Executive or defined control group only	Acquisition plans Personally identifiable information (PII)

Civilian programmes often align classifications with legal or contractual obligations (GDPR, PCI DSS, NDA scope) and integrate approvals into business workflows.

Classification Lifecycle

Treat classification as a living lifecycle, not a one-off event. Embed it into onboarding, project initiation, and change management.

Identify the business context: mission, regulatory obligations, threat landscape.
Catalogue data assets and map subjects (users, processes, devices) and objects (files, databases, messages).
Assign classification levels with justifying criteria and downgrade/upgrade rules.
Label data (metadata, watermarks, headers) so systems can act on the classification.
Apply controls: encryption, access controls, DLP policies, monitoring.
Review classifications periodically and when the data changes state (creation, sharing, storage, destruction).

Combine manual review with automated discovery (regex, fingerprinting, machine learning) to validate classifications at scale.

DLP Control Families

DLP tools must recognise classification labels and contextual signals to stop data leakage without blocking legitimate workflows.

Endpoint Agents

Monitor clipboard usage, file movements, and device control to prevent unauthorized exfiltration.

Network DLP

Inspect email, web, and cloud traffic for sensitive content patterns before it leaves the organisation.

Storage DLP

Scan on-prem and cloud repositories to identify and quarantine sensitive data at rest.

Cloud Access Security Broker (CASB)

Apply DLP policies to SaaS platforms with inline and API-based controls.

Pair preventive measures with detective controls (SIEM correlation, UEBA baselines) and corrective actions (ticketing, session quarantine) for full coverage.

Quick Reference Checklist

Label

Consistent naming convention (e.g., TS, Secret, Confidential).
Embed metadata in file properties and headers.
Apply visual cues (colour bands, watermarks) for end users.

Protect

Restrict subjects via RBAC/ABAC policies.
Encrypt at rest and in transit with strength aligned to classification.
Use DLP to detect attempted uploads, prints, or emails outside policy.

Monitor

Log subject/object interactions for forensics.
Alert on policy violations or unusual access patterns.
Re-evaluate classification when business context changes.