Exchange Online Protection
Office 365 includes hosted security filtering services designed to block unwanted and malicious e-mail and documents.
Roadmap for Exchange Online Protection, a Microsoft-hosted online service that filters incoming and outgoing e-mail for malware and spam and performs other filtering and routing tasks.
Two Office 365 services filter e-mail and documents for malware, spam, and other threats, and the most capable service requires a premium license
Microsoft hosts mail security and archiving services for Exchange Online that can also provide an Internet front end to an on-premises Exchange system