Exam 312-50v11 topic 1 question 226 discussion

Sam, a professional hacker, targeted an organization with intention of compromising AWS IAM credentials. He attempted to lure one of the employees of the organization by initiating fake calls while posing as a legitimate employee. Moreover, he sent phishing emails to steal the AWS IAM credentials and further compromise the employee's account.
What is the technique used by Sam to compromise the AWS IAM credentials?