EMAIL / Microsoft

Microsoft Defender for Office 365

Defender for Office 365 adds advanced email and collaboration protection to Microsoft 365. Analysts use native message context and, with Plan 2, investigation and response workflows in the Defender portal.

Native email and collaboration protectionResearch reviewed

What you are evaluating

Plan 2 is the scored scope. Exchange Online filtering, Plan 1 and Plan 2 are not interchangeable; cross-product endpoint response and additional identity products are outside this assessment.

A useful evaluation context

A useful comparison for a Microsoft 365 organization that wants advanced mail investigation within its existing provider; independently test its important mail paths.

Documented capabilities

The vendor describes these capabilities in the linked sources. Availability depends on the product edition and supported environment.

  • Safe Attachments and other threat policies add controls for supported messages and collaboration content.
  • Plan 2 provides Threat Explorer, incidents and automated investigation and response.
  • Quarantine policies distinguish user visibility, release requests and administrator-controlled release.

Where it fits in the work

  1. Confirm Plan 2 entitlement and deploy threat policies to a test population.
  2. Inspect a synthetic message in Explorer and connect its verdict to the applied policy.
  3. Approve the appropriate action and verify quarantine or restoration in the mailbox.

APPLY THE IDEA / ILLUSTRATIVE EXERCISE

Make the outcome observable.

A harmless test attachment is deliberately quarantined in a training mailbox.

Evidence to look for

Show the message evidence and explain why an end user can request release but cannot override certain malware or high-confidence phishing restrictions.

Use synthetic data and an authorized test environment. Agree the scope and recovery steps before enabling enforcement.

Questions for your evaluation

  1. Which users and shared mailboxes require the selected license?
  2. Who can inspect message content and approve release?
  3. Which collaboration workloads receive the same policy and which have different behavior?

Names you may encounter: Microsoft Defender for O365 · MDO. Historical names do not establish current availability or feature equivalence.

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