In cyber security, hierarchy is the layered ranking of trust, privilege, and decision-making inside a system or organization. It can describe who can approve changes, who can access sensitive data, which device or service is trusted above another, and how certificates or administrative roles depend on one another. A clear hierarchy helps systems work predictably, limits overreach, and makes accountability easier to enforce.
Hierarchy matters because attackers often try to climb it. Phishing, stolen credentials, and privilege-escalation attacks aim to move from low-level access to higher-value accounts, servers, or approval rights. Defenders counter this by flattening unnecessary power, using role-based access control, separating admin tiers, requiring multi-party approval, and protecting trust chains such as certificate authorities. Good hierarchy reduces the blast radius when one account, process, or device is compromised.