A malicious campaign is a coordinated series of harmful actions designed to deceive, steal, or disrupt. Instead of a single attack, it usually combines multiple steps such as fake messages, compromised software, fraudulent sites, or stolen accounts to reach many victims in a repeatable way.
This matters in cyber security because campaigns are often built for scale and persistence. Defenders look for shared infrastructure, reused code, common lures, and repeated behavior across incidents to connect separate events into one operation. In the browser-extension case, the campaign concept helps explain how a trusted add-on layer can be used to target many users and create a broad theft path. Recognizing a campaign early supports faster detection, takedown, user warnings, and blocking of related activity.