Microsoft informed administrators on Monday that Application Guard for Office, a feature designed to protect users against malicious documents, is now available in public preview.
Application Guard for Office (its full name is Microsoft Defender Application Guard for Office) has been available in private preview. The feature, which is currently disabled by default, is available to customers who have a 365 E5 or 365 E5 Security license.
Application Guard for Office prevents untrusted files from accessing trusted resources by running potentially unsafe Office files in a secure container isolated through hardware-based virtualization.
“When Office opens files in Application Guard, users can securely read, edit, print, and save those files without having to re-open files outside the container,” explained Eric Wayne, a senior Office deployment engineer at Microsoft.
Microsoft has provided detailed instructions for enabling Application Guard for Office. The company pointed out that when the feature is enabled, users will be informed both in the Office splash screen when they open an untrusted file, and while they are working with the opened file.
Microsoft is also offering Windows Defender Application Guard for its Edge and Internet Explorer web browsers, which is designed to provide protection against malicious files downloaded from the internet.
Related: Microsoft Brings Safe Documents, Application Guard to More 365 ProPlus Users
Related: Microsoft Makes Automated Incident Response in Office 365 ATP Available
Related: Microsoft Adds New Security Features to Office 365
Related: Researcher Details Sophisticated macOS Attack via Office Document Macros

Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.
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