We have seen this in the wild.  The users are targeted and it seems legit.  The key to not falling for this stuff is communication.

Since the FBI’s Internet Crime Complaint Center (IC3) began tracking BEC scams in late 2013, it has compiled statistics on more than 7,000 U.S. companies that have been victimized—with total dollar losses exceeding $740 million. That doesn’t include victims outside the U.S. and unreported losses, the FBI stated. According to IC3, since the beginning of 2015 there has been a 270% increase in identified BEC victims.

Source: FBI: Major business e-mail scam blasts 270% increase since 2015