The training manual contains theoretical material on the basics of penetration testing. The manual systematically describes and describes the main stages of penetration testing by security researchers, in particular, the process of collecting information, the process of obtaining information from network services (network scanning), the procedure for finding and exploiting vulnerabilities, as well as exploiting vulnerabilities in web applications. The training manual contains educational tasks performed in the form of laboratory work, which serve to consolidate and assimilate the acquired skills.