Helping users stay safe: Blocking internet macros by default in Office

Updated July 20, 2022:

We’re resuming the rollout of this change in Current Channel. Based on our review of customer feedback, we’ve made updates to both our end user and our IT admin documentation to make clearer what options you have for different scenarios. For example, what to do if you have files on SharePoint or files on a network share. Please refer to the following documentation:

•            For end users, A potentially dangerous macro has been blocked 

•            For IT admins, Macros from the internet will be blocked by default in Office

 

If you ever enabled or disabled the Block macros from running in Office files from the Internet policy, your organization will not be affected by this change.

 

Update July 8, 2022:

Following user feedback, we have rolled back this change temporarily while we make some additional changes to enhance usability. This is a temporary change, and we are fully committed to making the default change for all users. 

 

Regardless of the default setting, customers can block internet macros through the Group Policy settings described in this article. 

 

We will provide additional details on timeline in the upcoming weeks.

 

It’s a challenging time in software security; migration to the modern cloud, the largest number of remote workers ever, and a global pandemic impacting staffing and supply chains all contribute to changes in organizations. Unfortunately, these changes also give bad actors opportunities to exploit organizations:

 

 

For years Microsoft Office has shipped powerful automation capabilities called active content, the most common kind are macros. While we provided a notification bar to warn users about these macros, users could still decide to enable the macros by clicking a button. Bad actors send macros in Office files to end users who unknowingly enable them, malicious payloads are delivered, and the impact can be severe including malware, compromised identity, data loss, and remote access. See more in this blog post.

 

 

For the protection of our customers, we need to make it more difficult to enable macros in files obtained from the internet.

 

Changing Default Behavior

We’re introducing a default change for five Office apps that run macros:

 

VBA macros obtained from the internet will now be blocked by default.

 

For macros in files obtained from the internet, users will no longer be able to enable content with a click of a button. A message bar will appear for users notifying them with a button to learn more. The default is more secure and is expected to keep more users safe including home users and information workers in managed organizations.

 

 

This change only affects Office on devices running Windows and only affects the following applications: Access, Excel, PowerPoint, Visio, and Word. The change will begin rolling out in Version 2203, starting with Current Channel (Preview) in early April 2022. Later, the change will be available in the other update channels, such as Current Channel, Monthly Enterprise Channel, and Semi-Annual Enterprise Channel.

 

At a future date to be determined, we also plan to make this change to Office LTSC, Office 2021, Office 2019, Office 2016, and Office 2013.

 

End User Experience

Once a user opens an attachment or downloads from the internet an untrusted Office file containing macros, a message bar displays a Security Risk that the file contains Visual Basic for Applications (VBA) macros obtained from the internet with a Learn More button.

 

A message bar displays a Security Risk showing blocked VBA macros from the internet

 

The Learn More button goes to an article for end users and information workers that contains information about the security risk of bad actors using macros, safe practices to prevent phishing & malware, and instructions on how to enable these macros by saving the file and removing the Mark of the Web (MOTW).

 

What is Mark of the Web (MOTW)?

The MOTW is an attribute added to files by Windows when it is sourced from an untrusted location (Internet or Restricted Zone). The files must be saved to a NTFS file system, the MOTW is not added to files on FAT32 formatted devices.

 

IT Administrator Options

This chart shows the evaluation flow for Office files with VBA macros and MOTW:

Evaluation flow for Office files with VBA macros and MOTW

Organizations can use the “Block macros from running in Office files from the Internet” policy to prevent users from inadvertently opening files from the internet that contain macros. Microsoft recommends enabling this policy, and if you do enable it, your organization won’t be affected by this default change.

 

 

Additionally, there are two other options to know your files are safe:

• Opening files from a Trusted Location
• Opening files with digitally signed macros and providing the certificate to the user, who then installs it as a Trusted Publisher on their local machine

To learn more about how to get ready for this change and recommendations for managing VBA macros in Office files, read this article for Office admins.

 

Thank you,

Office Product Group
VBA Team & Office Security Team

 

More helpful information on the threats of Ransomware:

• The growing threat of ransomware, Microsoft "On the Issues" blog post on July 20, 2021
• Rapidly protect against ransomware and extortion
• 2021 Microsoft Digital Defense Report (see pages 10-19)
• Learn about threat analytics in Microsoft 365 Defender
• Microsoft’s DART ransomware approach and best practices
• Microsoft DART ransomware case study

 

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