Email is a store-and-forward messaging system: a message is sent to a mail server, stored, and then delivered to the recipient’s mailbox when their system is available. Because it is simple, standardized, and widely supported, email remains a core channel for business, personal communication, and automated notifications.
In cyber security, email matters because it is trusted by default and used for logins, password resets, alerts, and account recovery. Attackers abuse that trust with phishing, spoofing, malicious attachments, and links to credential theft pages. Defenders reduce risk with spam and malware filtering, sender authentication such as SPF, DKIM, and DMARC, and strong user awareness. Email is also a defense channel: it carries security warnings, verification codes, and incident response notices, so protecting it helps protect many other systems.