In November of 2021, we described several techniques used by attackers to deliver malware through infected Microsoft Office files. In addition to exploits like CVE-2021-40444, these infected documents frequently abuse VBA (Visual Basic for Applications) to execute their techniques, regardless of the final payload. Attackers also often use extra layers of protection to evade signature-based detections, like constructing PowerShell scripts and WMI namespaces at runtime, as done by Emotet.

Microsoft Teams has exploded in popularity in recent years, going from 2 million users in 2017 to roughly 250 million today. That growth is due in no small part to the disruptions caused by the global pandemic, with employees working from home and still needing to collaborate.