What is a characteristic of a computer virus?

A computer virus is defined by its ability to replicate itself and spread to other systems, often without the user's consent. The key characteristic is that a virus attaches itself to legitimate software or files, allowing it to hijack the resources of a computer system and replicate itself. This unauthorized replication can lead to various harmful effects, including data corruption, system slowdown, or additional malware distribution.

The other options do not describe characteristics of a computer virus. For instance, physical damage to hardware refers to tangible damage that may occur to physical components of a computer, but this is not a function of a virus. Protection against malware is an attribute of antivirus software designed to prevent malicious software, including viruses, from infecting a system rather than a characteristic of a virus itself. Secure communication between devices involves encryption and secure protocols, which are unrelated to the functionality of a virus. Therefore, the defining characteristic of a computer virus lies in its capacity for unauthorized replication.