What is the main purpose of rootkits?

Rootkits are primarily designed to provide remote control over a targeted system while remaining stealthy to both users and security software. When a rootkit is installed, it integrates itself into the operating system, enabling an attacker to execute commands, manipulate processes, and alter system configurations without detection. This capability allows the attacker to control the system remotely, often without the legitimate user's knowledge, making rootkits a serious security threat.

While the capability to hide files from the user is a feature of rootkits, it is not their main purpose. The other options, such as speeding up system performance or propagating viruses, relate to separate functionalities or malware types. Rootkits focus specifically on stealthy control and persistence within an operating system, prioritizing remote access as their primary function.