Phishing is a cyber attack that uses disguised email as a weapon. The goal is to trick the email recipient into believing that the message is something they want or need — a request from their bank, for instance, or a note from someone in their company — and to click a link or download an attachment.

What really distinguishes phishing is the form the message takes: the attackers masquerade as a trusted entity of some kind, often a real or plausibly real person, or a company the victim might do business with. It’s one of the oldest types of cyberattacks, dating back to the 1990s, and it’s still one of the most widespread and pernicious, with phishing messages and techniques becoming increasingly sophisticated.