In software, a hook is an automatic callback: code or a command that runs when an application event occurs, such as startup, file open, login, or shutdown. Hooks can be built into an app, added by plugins, or configured by the user. They are useful because they automate repetitive actions and let security tools inspect or block activity at the right moment.
Hooks matter in cyber security because they execute with the privileges of the process or user that triggered them. That makes them a common target in attacks: if an attacker can alter a hook definition, supply malicious input to a hookable event, or abuse a weakly validated configuration override, they may get unintended code execution. Defenders should inventory hooks, limit what they can run, validate event data, and treat any command launched automatically as part of the trusted computing base.