An intranet is a private internal network used within an organization. Unlike the public internet, it is meant to be reachable only by trusted users, devices, and services, often through internal addressing, authentication, and access controls. In practice, an intranet may support email, portals, file shares, business apps, or administrative systems that should not be exposed to outsiders.
In cyber security, intranets matter because they concentrate sensitive data and privileged workflows behind a trust boundary. Attackers try to enter through stolen credentials, phishing, misconfigured remote access, or a compromised endpoint, then move laterally inside the network. Defenders protect intranets with segmentation, strong identity checks, logging, least privilege, and monitoring for unusual internal activity. A claim about an intranet breach should always be verified with telemetry and logs, not assumed from a public label alone.