Citing a growth in macro-borne threats, Microsoft has opted to give Office 2013 users a feature from Office 2016 to selectively block macros and the malware they can carry.
Office macros are a double-edged sword for the enterprise. They can improve productivity by automating routine tasks in Excel and Word, but they can be coded to deliver malware.
Even though it's been possible since the days of Office 97 to disable macros by default, users have always had the option of enabling them, which has presented attackers with a way of spreading malware since the Melissa virus in 1999. More recently, macros have been used to deliver banking Trojans and ransomware.
Fortunately, Microsoft earlier this year introduced a new feature in Group Policy for Office 2016 that allowed admins to block macros from loading in risky scenarios, such as when staff are opening Office email attachments from unknown senders, or when opening a file from Dropbox. Admins could also allow macros to run for certain trusted workflows.