What characteristic defines a computer virus?

A computer virus is characterized primarily by its ability to self-replicate and disrupt normal computer operations. This means that a virus can make copies of itself and spread to other files or programs on the computer and potentially across networks. The disruption can manifest in various ways, such as corrupting files, monitoring user activity without consent, or slowing down system performance.

Self-replication is a fundamental trait separating viruses from other types of software; while many programs can perform tasks or have effects on a computer, a virus specifically aims to spread and cause interference. This behavior can lead to significant security risks and damage, making it crucial for users to have protective measures in place.

Other characteristics listed, such as requiring user permission to operate or being created for educational purposes, do not define a virus. In many cases, viruses can execute without explicit user consent or knowledge, highlighting their malicious nature.