Introduction. Ensuring the economic security of the population highlights the need of understanding various types of threats to citizens’ financial resources. During the period of active digitalisation of social relations, there has been a significant increase in fraudulent activities using social engineering methods, raising the importance of scientific knowledge of rational consumer behaviour. Its components – the cognitive characteristics of an economic agent, their critical thinking skills and possession of specialised (financial) knowledge – are assessed as factors in counteracting manipulation and involvement in fraudulent schemes. Methods. The research was based on general scientific methods, including analysis and synthesis of information on contemporary theories and concepts of rational behaviour, as well as generalisation applied for the purpose of systematising scientific knowledge on the rational behaviour of an economic agent. Results. The author describes three factors reducing the level of critical thinking among economic agents and increasing the likelihood of them making irrational decisions (fundamental cognitive limitations, lack of specialised knowledge, and the quality of the digital environment). The mechanisms behind the manipulation of these factors in digital fraud are revealed. These findings made it possible to identify vulnerabilities and risks in different age groups and to formulate prevention strategies.