The attack surface refers to the total number of points in a computer system, network, or application where an unauthorized user, such as a hacker, could attempt to gain access or extract data. This includes hardware, software, network interfaces, user accounts, and any other potential entry points. Reducing the attack surface is a key cybersecurity strategy, as it limits the opportunities for attackers to exploit vulnerabilities. A smaller attack surface means fewer places to defend and less risk of a security breach.