Explanation/Notes: Social engineers are adept at deceiving employees into inadvertently vouching for their identity. One social engineering trick is to obtain the telephone number of the receptionist and, on a pretext, ask the receptionist to take any messages that may come for him. Then, during a call to the victim, the attacker pretends to be an employee, asks for some sensitive information or to perform a task, and gives the main switchboard number as a callback number. The attacker later calls back to the receptionist and is given any message left for him by the unsuspecting victim.