According to experts, cyber security ranks third in terms of its importance to humanity, just behind climate threats. Incursions into personal business space and the theft of personal data are some of the most frequent examples of mass cyberattacks. For instance, Indias Aadhar government database was compromised in 2018, which resulted in the theft of 1.1 billion personal accounts. On this occasion, the victims were not only commercial and government structures but also citizens, who often remain defenceless in the face of cyber risks. The increased frequency of such incidents as well as their growing scale is a new source of anxiety for Internet users worldwide and demand greater attention from both corporate and government structures. What makes massive identity theft possible? How do cybercriminals use peoples personal data? How do massive data thefts affect customer loyalty and consumer behaviour? What methods can be used to protect against such attacks? What measures are companies and the Internet portals of government agencies taking to protect their customers from such attacks in Russia and around the world?