Microsoft blocks internet-downloaded XLL add-ins to prevent malware spread

January 24, 2023

Microsoft says it will implement a new security measure to discourage hackers from using XLL add-ins to distribute malware.

Adversaries abusing Microsoft add-ins is a hobby due to its pervasiveness in corporate environments and personal computers, allowing threat actors to get a lot of mileage out of their malware.

The plan to implement the new measures resulted in the goal of combating the increasing number of malware attacks that have become more prevalent in recent months. According to Microsoft’s 365 roadmap, it will soon be available to worldwide desktop users of its Excel product in the Monthly Enterprise Channel, Semi-Annual Enterprise Channel, General Availability, Preview, and Current Channel.

“In order to combat the increasing number of malware attacks in recent months, we are implementing measures that will block XLL add-ins coming from the internet,” Microsoft says.

According to Microsoft, the new feature will be available in multi-tenant mode for desktop users in the Current, Monthly Enterprise, and Semi-Annual Enterprise channels in March.

After the changes are implemented, Microsoft 365 users will have improved protection that will prevent XLL add-ins from being downloaded from the internet. This means protection from bad actors who use the web to distribute malware. While the general availability of the upcoming capability is still subject to change, its arrival will be a significant improvement in Microsoft customers’ security.

The sources for this piece include an article in BleepingComputer.

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Jim Love

Jim is an author and podcast host with over 40 years in technology.

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