Business email compromise (BEC) is a type of targeted phishing attack where an attacker gains access to a legitimate business email account (or convincingly impersonates one) to manipulate financial transactions, such as redirecting payments to a fraudulent bank account. The scenario described matches this pattern.
Reference:
CompTIA Security+ SY0-701 Official Study Guide, Domain 2.2: "Business email compromise involves manipulating legitimate business communications to divert funds or sensitive information." Exam Objectives 2.2: "Given a scenario, analyze potential indicators associated with application attacks."