A multitude of studies have suggested potential factors that influence internet security awareness (ISA). Some, for example, used GDP and nationality to explain different ISA levels in other countries but yielded inconsistent results. This study proposed an extended knowledge-attitude-behaviour (KAB) model, which postulates an influence of the education level of society at large is a moderator to the relationship between knowledge and attitude. Using exposure to a full-time working environment as a proxy for the influence, it was hypothesized that significant differences would be found in the attitude and behaviour dimensions across groups with different conditions of exposure and that exposure to full-time work plays a moderating role in KAB. To test the hypotheses, a large-scale survey adopting the Human Aspects of Information Security Questionnaire (HAIS-Q) was conducted with three groups of participants, namely 852 Year 1–3 students, 325 final-year students (age = 18–25) and 475 full-time employees (age = 18–50) in two cities of China.