This is the least common social engineering attack and is not as technically advanced as the ones we've discussed previously. However, it does have a significant success rate. Attackers use this method to gain entry into restricted premises or parts of buildings. Most organizational premises have electronic access control and users normally require biometric or RFID cards to be allowed in. An attacker will walk behind an employee that has legitimate access and enter behind them. At times, the attacker may ask an employee to borrow their RFID card, or may gain entry by using a fake card under the guise of accessibility problems.