Paul's company is in the process of undergoing a complete security audit including logical and physical security testing. After all logical tests were performed; it is now time for the physical round

Paul's company is in the process of undergoing a complete security audit including logical and physical security testing. After all logical tests were performed; it is now time for the physical round to begin. None of the employees are made aware of this round of testing. The security- auditing firm sends in a technician dressed as an electrician. He waits outside in the lobby for some employees to get to work and follows behind them when they access the restricted areas. After entering the main office, he is able to get into the server room telling the IT manager that there is a problem with the outlets in that room. What type of attack has the technician performed?