Rootkit is a malicious program that can hide its own actions from antivirus: registry entries, system processes, network connections and files. Sometimes this software masks the work of other malicious programs, such as Trojans. The functionality of rootkits can range from stealing data to remotely controlling system processes.
The term “rootkit” is the result of two other terms: “root” (superuser) and “kit” (toolkit). In other words, such software is a tool for system actions with administrator rights.
Rootkits are downloaded under the guise of free programs, installed from external drives (flash drives and portable hard drives), hidden behind banners on infected sites.