"You then get connected to an Indian call center, where a person directs you to a Web site to download an infected Word document with a macro and talks you through enabling the macros," he says. "And because of that human element, I'm suspecting that they are getting a higher success rate." Microsoft Office documents with malicious macros — often called "maldocs" — have resurged as a vector to infect systems, growing in the last half of 2020 to account for more than a third of malicious attachments and, at one point in September 2020, accounting for almost 80% of malicious attachments, according to data from Sophos.