In response to the threat of phishing, web browsers display warnings when users arrive at suspected phishing websites. Previous research has offered guidance to improve these warnings. We performed a laboratory study to investigate how the choice of background color in the warning and the text describing the recommended course of action impact a userâ€™s decision to comply with the warning. We did not reveal to participants that the subject of the study was the warning, and then we observed as they responded to a simulated phishing attack. We found that both the text and background color had a significant effect on the amount of time participants spent viewing a warning, however, we observed no significant differences with regard to their decisions to ultimately obey that warning. Despite this null result, our exit survey data suggest that misunderstandings about the threat model led participants to believe that the warnings did not apply to them. Acting out of bounded rationality, participants made conscientious decisions to ignore the warnings. We conclude that when warnings do not correctly align usersâ€™ risk perceptions, users may unwittingly take avoidable risks.
Serge Egelman and Stuart Schechter. The importance of being earnest [in security warnings]. In A.-R. Sadeghi, editor, Financial Cryptography and Data Security, volume 7859 of Lecture Notes in Computer Science, pages 52-59. Springer Berlin Heidelberg, 2013.