A cyberattack is a deliberate attempt to disrupt, steal from, damage, or gain unauthorized access to a computer system, account, network, or data set. It can target availability, confidentiality, or integrity, and it may use phishing, malware, stolen passwords, software exploits, or denial-of-service traffic.
Cyberattacks matter because they are often the first step in a wider criminal chain. An intrusion can lead to stolen data, fraud, account takeover, or ransomware, and the profit from those actions may be reused to support other abuse. In defense, the goal is to make attacks harder to launch and less useful if they succeed: patch systems quickly, require strong authentication, limit privileges, watch for unusual logins, and contain compromised accounts fast. Even when the full scope of an incident is unclear, treating the event as a potential cyberattack helps teams respond before damage spreads.