Threat vectors: email, SMS, voice, removable media, supply chain, open ports

A threat vector (also called an attack vector) is the path or method an attacker uses to reach a target. The attack surface is the total set of vectors available against an organization: every email inbox, exposed service, device, supplier connection and user who can be tricked. Reducing the attack surface means closing or controlling as many vectors as possible. Security+ lists a set of common vectors and expects you to identify them in scenarios and pick sensible defenses for each.