Abstract. Today, web applications are firmly integrated into our daily lives. We not only use them as games and information resources, but also as means of orders and payments. Naturally, by conducting online payments, registrations and other similar actions, we transfer part of our personal data, as well as card data, phones, etc. Once in the hands of attackers, this data can cause irreparable harm. In this regard, the protection of web applications and services is seen as a very important aspect of modern network security. The content of this paper will be useful both to specialists in the field of information security and to ordinary users.