A relay node in cybersecurity refers to a device or system that forwards network traffic between different points, often to obscure the original source or destination of the data. Relay nodes are commonly used in both legitimate privacy-focused networks, like Tor, and in malicious activities, such as botnets or cyberattacks. In malicious contexts, attackers compromise systems to act as relay nodes, making it difficult for defenders to trace the true origin of the attack or the final target. This technique is frequently employed to bypass security controls, evade detection, and anonymize malicious activities.