Microsoft will block the ability to load add-ins from the Internet into Excel. According to the company, this ability has been increasingly abused in recent months to distribute malware.
Microsoft writes in a roadmap that it will block Excel add-ins from the Internet from March. These are XLL files that can be used to add extra functionality to the spreadsheet software. Add-ins, unlike add-ons, do not need to be installed as an executable file. They can be loaded directly at the same time as Excel itself. This is certainly problematic with Microsoft 365 products, because Excel can be used online there. That only applies to Excel; with other Office applications, such as Word, only admins can load add-ins.
According to Microsoft, this poses a security risk. For example, an XLL add-in can be loaded into Excel from different sides. This can be done via phishing websites, but also via e-mail. In addition, an XLL can be programmed to run code on a system and thus cause relatively high levels of damage.
According to Microsoft, there has been an increase in malware spread via add-ins in recent months. spread, but the company gives few specific details about that. “Due to the increase in malware attacks in recent months, we are taking measures to block XLL add-ins coming from the Internet,” Microsoft writes. From that moment on it is only possible to load add-ins from the local system.
