Every running service on a Linux server is a potential attack surface, and systemd — the process manager on nearly all modern distributions — controls not just whether a service starts, but under what identity, with what resource limits, and with what access to the rest of the filesystem it runs. Hardening a service is rarely about the application's own code; it is usually about constraining the environment systemd hands that code, so that even if the application is compromised, the damage it can do is bounded.
Analogy🏏Cricket
💪 Think of it like fitness: injuries follow a predictable chain — poor warm-up, then form breakdown, then compensation, then the actual tear — and a good physio catalogs where each patient's chain can be interrupted early, rather than only treating the tear afterward. MITRE ATT&CK is the sports-medicine literature of intrusions: a public catalog of every observed breakdown pattern, organized by the stage it serves — how attackers get in, how they escalate, how they extract. Coaches worldwide describe an athlete's risk in that shared vocabulary. This reveals ATT&CK's real value: intrusions become a sequence you can interrupt at stage two, not a disaster you discover at stage five.