Cyber Intelligence
Microsoft Defender XDR · 25-30% of exam

L2. Defender for Endpoint: Onboarding and Alert Triage

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Check back soon for the video lesson on Defender for Endpoint: Onboarding and Alert Triage

Defender for Endpoint protects devices through behavioral sensors, cloud analytics, and threat intelligence. This lesson covers onboarding methods, the alert queue, automated investigation, and the response actions SC-200 candidates must know.

Defender for Endpoint Architecture

Microsoft Defender for Endpoint (MDE) uses behavioral sensors embedded in Windows, macOS, Linux, Android, and iOS to collect telemetry. This data flows to the Microsoft cloud backend for analysis against threat intelligence and behavioral models.

Key components:

  • Endpoint behavioral sensors: Collect process, network, registry, and file signals
  • Cloud security analytics: Machine learning models that detect anomalies
  • Threat intelligence: Microsoft and third-party IOCs and attack pattern matching

Onboarding Methods

The SC-200 exam tests your knowledge of onboarding approaches:

MethodBest For
Microsoft IntuneCloud-managed devices at scale
Group PolicyDomain-joined Windows endpoints
Local scriptTesting and small deployments
Microsoft Endpoint Configuration Manager (MECM)On-premises managed environments
VDI onboarding scriptNon-persistent virtual desktops
Exam tip: For non-persistent VDI environments, use the dedicated VDI onboarding script, not the standard local script. The VDI script handles session cleanup differently.

The Alert Queue and Triage

When MDE detects suspicious activity, it generates alerts with severity levels: Informational, Low, Medium, and High. Analysts triage alerts using these classifications:

  • True positive: Confirmed malicious activity requiring response
  • True positive (benign): Suspicious but expected behavior (e.g., a pen test)
  • False positive: Incorrectly flagged legitimate activity

The alert page shows a process tree, file details, device timeline, and related alerts. Use the device timeline to reconstruct the full sequence of events on an endpoint.

Automated Investigation and Response (AIR)

MDE can automatically investigate alerts and take remediation actions. AIR examines:

  • Running processes and services
  • Scheduled tasks
  • Registry modifications
  • Files and persistence mechanisms

Automation levels control how AIR behaves:

LevelBehavior
Full automationRemediate threats automatically
Semi (any folder)Require approval for all remediations
Semi (non-temp)Auto-remediate in temp folders, require approval elsewhere
Semi (core folders)Require approval for core OS folder remediations
No automationNo automated response
Exam tip: Full automation is the recommended setting for most organizations. Semi-automation is used when SOC teams want to review actions before execution.

Response Actions

Key response actions available on devices:

  • Isolate device: Cuts network access while maintaining Defender cloud connectivity
  • Restrict app execution: Limits execution to Microsoft-signed binaries only
  • Run antivirus scan: Triggers a quick or full scan remotely
  • Collect investigation package: Gathers forensic data from the endpoint
  • Initiate live response: Opens a remote shell session for manual investigation

File-level actions include: stop and quarantine, add indicators (block/allow), and download file for analysis.

Device Groups

Device groups let you segment your fleet and apply different automation levels, RBAC permissions, and remediation policies. Group membership is determined by device tags, names, domains, or OS types.

Exam Focus Points
  • Onboarding methods include Intune, Group Policy, local script, MECM, and VDI-specific scripts.
  • Non-persistent VDI environments require the dedicated VDI onboarding script.
  • Automated Investigation and Response (AIR) has four automation levels from full to no automation.
  • Device isolation cuts network access but maintains the Defender cloud connection for management.
  • Alert classifications are: true positive, true positive (benign), and false positive.
  • Device groups enable segmented automation levels and RBAC scoping.
Knowledge Check

1. An organization uses non-persistent VDI sessions. Which onboarding method should they use for Defender for Endpoint?

2. A SOC analyst isolates a compromised device using Defender for Endpoint. What network connectivity does the device retain?

3. Which automation level requires analyst approval for all remediation actions?