The paper is devoted to the study of the possibility of applying the main methods of assessing the reliability of information technology systems, including a review of existing developments in this field and analysis of the basic principles of testing systems. Special attention is paid to methods for evaluating the reliability of software. This paper describes the main steps that should be taken by an attacker in a cyber-attack. Methods of vulnerability detection using graph theory are considered and methods of their elimination are shown. The possibility of using neural networks for traffic analysis in order to detect signatures is considered. The mechanism of DDoS attacks is considered and the main mechanisms of protection against them are analyzed. Mechanisms for changing the topology of information technology systems through the use of graph theory were tested on decentralized systems and showed a significant increase in the system’s resistance to unauthorized access. Mechanisms to prevent DDoS attacks through the use of neural networks allowed real-time tracking of unwanted content and reduced the time required to update databases of malicious signatures.