What is a rootkit?

A rootkit is specifically designed to grant unauthorized access to a computer or network while concealing its presence. This stealth capability allows it to operate undetected by traditional security measures, making it particularly dangerous. Once a rootkit is installed on a system, it can enable an attacker to execute malicious commands, steal sensitive information, or manipulate software without the user's awareness. Rootkits often modify operating system components and can embed themselves deeply within the system, complicating their detection and removal.

The other options describe different types of software or malware that do not align with the specific characteristics of a rootkit. For example, software that boosts system performance is typically focused on optimization rather than covert access. An application that manages network traffic concerns itself with routing and handling data flow rather than malicious access. A self-replicating virus is more about spreading and infecting systems rather than stealthily maintaining a foothold on a single compromised system. Thus, the defining aspect of a rootkit relates to its malicious intent and concealment capabilities.