Network tunneling is the practice of relaying network traffic through one host or protocol so it appears to come from somewhere else. In legitimate use, tunneling helps remote access, VPNs, and secure service connections. In attacker hands, it can hide command-and-control traffic, bypass firewalls, or let an operator reach internal systems through a compromised machine.
In real intrusions, tunneling often appears after initial access. Malware or an interactive operator may open a proxy, SSH tunnel, or port-forwarding channel that forwards requests between the attacker and the victim network. This can make suspicious traffic blend in with normal connections and let attackers move laterally without directly exposing their infrastructure. Defenders look for unusual outbound connections, unexpected proxy behavior, and internal services being accessed through an endpoint that should not normally relay traffic. Network logs, endpoint telemetry, and identity events together can reveal this pattern.