Objectives The aim of the current study is to explore to what extent an intervention reduces the effects of social engineering (e.g., the obtaining of access via persuasion) in an office environment. In particular, we study the effect of authority during a ‘social engineering’ attack. Methods Thirty-one different ‘offenders’ visited the offices of 118 employees and on the basis of a script, asked them to hand over their office keys. Authority, one of the six principles of persuasion, was used by half of the offenders to persuade a target to comply with his/her request. Prior to the visit, an intervention was randomly administered to half of the targets to increase their resilience against attempts by others to obtain their credentials. Results A total of 37.0 % of the employees who were exposed to the intervention surrendered their keys while 62.5 % of those who were not exposed to it handed them over. The intervention has a significant effect on compliance but the same was not the case for authority. Conclusions Awareness-raising about the dangers, characteristics, and countermeasures associated with social engineering proved to have a significant positive effect on neutralizing the attacker.