Built-in security features for cloud mailboxes service description

Exchange Online mailboxes come with built-in security features. These are focused on spam filtering and blocking common malware attacks in email traffic to protect against basic email threats. These features are included with every Exchange Online cloud mailbox and available as an add-on for Exchange on-premises mailboxes. For comprehensive email security, including phishing prevention, post-delivery remediation, threat investigation, and end-user resilience, learn more about Microsoft Defender for Office 365 Plan 1 and Plan 2.

Service details

  • Deployment: No setup required; protection is applied automatically.

  • Management: Administrators can view filtering reports and adjust basic settings via the Microsoft 365 admin center.

  • Integration: Works seamlessly with Exchange Online and other Microsoft 365 services.

Advanced email protection

For organizations seeking enhanced security beyond baseline protection, Microsoft Defender for Office 365 offers:

  • Defender for Office 365 Plan 1: Available in certain Microsoft 365 subscriptions for small to medium-sized businesses, such as Microsoft 365 Business Premium. This plan provides protection against advanced and zero-day phishing, malware, and other email-based threats, including features like Safe Links, Safe Attachments, and real-time threat detection.

  • Defender for Office 365 Plan 2: Included in enterprise-level Microsoft 365 subscriptions, such as Microsoft 365 E5, A5, and GCC G5. This plan offers all the capabilities of Plan 1, plus AST and SOC capabilities such as advanced threat hunting, automation, and investigation tools. It is designed for organizations needing greater visibility, response capabilities, and support for compliance.

Learn more

Exchange Enterprise CAL with Services features

Microsoft Exchange Enterprise CAL with Services provides the email protection of built-in security features and the following additional cloud-based features:

For more information about Exchange Enterprise CAL with Services licensing, see Exchange licensing FAQs.

If you have Exchange Enterprise CAL with Services licenses and you want to provision built-in security features, follow the instructions in Set up your EOP service. The setup steps are the same as the steps for setting up built-in security features standalone.

Note

New features for Exchange Enterprise CAL with Services are deployed at the same time as Exchange Online, not EOP standalone. Be advised that the deployment schedules for EOP standalone and Exchange Online/Exchange Enterprise CAL with Services may be slightly different.

Feature availability

The following table lists built-in security features available for cloud mailboxes and across plans. See the footnotes for more information. For the most up-to-date, complete list of features, see Powerful tools to support your enterprise.

Feature Built-in security for on-premises mailboxes add-on Built-in security features in EE CAL w/ Services Built-in security features for cloud mailboxes
Protection
Anti-malware policies (built-in and custom) Yes Yes Yes
Inbound anti-spam policies (built-in and custom) Yes Yes Yes
Outbound anti-spam policies (built-in and custom) Yes Yes Yes
Connection filtering (IP Allow list and IP Blocklist) Yes Yes Yes
Anti-phishing policies (built-in and custom) Yes Yes Yes
Anti-spoofing protection (built-in and custom) Yes Yes Yes
Zero-hour auto purge (ZAP) for delivered malware, spam, and phishing messages10 No No Yes
Preset security policies Yes Yes Yes
Configuration analyzer for protection policies Yes Yes Yes
Tenant Allow/Blocklist Yes Yes Yes
Blocklists for message senders Yes Yes Yes
Allow lists for message senders Yes Yes Yes
Edge blocking Yes Yes Yes
Directory Based Edge Blocking (DBEB) for nonexistent recipients Yes Yes Yes
Quarantine and submissions
Admin submission10 No No Yes
User submission (custom mailbox)10 No No Yes
Admin quarantine Yes Yes Yes
End-user quarantine Yes Yes Yes
Report Message add-in and Report Phishing add-in for Outlook Yes Yes Yes
Mail flow
Mail flow rules (transport rules)4 Yes Yes6 Yes
Accepted domains3 Yes Yes Yes
Connectors Yes Yes Yes
Enhanced Filtering for Connectors (skip listing) Yes Yes Yes
Monitoring
Message trace Yes Yes Yes
Email and security reports in the Microsoft 365 admin center Yes7 Yes7,8 Yes8
Security reports in the Microsoft 365 security center Yes7 Yes7,8 Yes8
Email reports in the EAC Yes7 Yes7,8 Yes8
Admin audit logging5 Yes Yes Yes
Users
Mail users and mail contacts1 Yes Yes Yes
Mailboxes No No Yes1a
Role based access control (RBAC)2 Yes Yes Yes
Compliance
Data Loss Prevention for email No Yes Yes
Microsoft Purview Message Encryption No9 No9 Yes
Administration
Microsoft 365 admin center Yes Yes Yes
Exchange admin center Yes Yes Yes
Microsoft 365 security center Yes Yes Yes
Standalone Exchange Online Protection PowerShell Yes No No
Exchange Online PowerShell No Yes Yes

1 You create, remove, and edit mail users and mail contacts in the EAC.
1a You create and remove mailboxes in the Microsoft 365 admin center. You can edit existing mailboxes in the EAC.
2 In standalone EOP and EE CAL with Services, there are no end-user roles or role assignment policies.
3 You add and remove domains in the Microsoft 365 admin center. In the EAC, you configure domains as Authoritative or Non-Authoritative.
4 A few rule conditions, exceptions, and actions are not available in standalone EOP or the EOP in EE CAL with Services. These differences are clearly noted in Exchange Online mail flow rule content.
5 In standalone EOP and EE CAL with Services:

  • Mailbox auditing reports aren't available.
  • The Administrator role group report and Admin audit log report are the only admin auditing reports in the EAC.
  • Audit log export available only via PowerShell.

6 DLP policy tips are not available in EE CAL with Services.
7 Reports in standalone EOP and EE CAL with Services are a subset of Exchange Online reports (reports that deal with mailboxes).
8 Includes DLP reports.
9 You can purchase Azure Information Protection as an add-on subscription and use OME if you configure your on-premises email environment to route email to and from the internet through EOP.
10 This feature requires Exchange Online mailboxes.

Learn more

For technical information about built-in security features for cloud mailboxes, check out the following resources:

Licensing terms

For licensing terms and conditions for products and services purchased through Microsoft Commercial Volume Licensing Programs, see the Product Terms site.

Messaging

To keep track of upcoming changes, including new and changed features, planned maintenance, or other important announcements, visit the Message Center. For more information, see Message center.

Accessibility

Microsoft remains committed to the security of your data and the accessibility of our services. For more information, see the Microsoft Trust Center and the Office Accessibility Center.