Answer: rootkit
Step-by-step explanation:
Hi, A rootkit is a collection of computer software, typically malicious, designed to enable access to a computer or an area of its software that is not otherwise allowed (for example, to an unauthorized user) and often masks its existence or the existence of other software.
A rootkit provides continued privileged access to a computer while hiding its presence. Because of this hiding characteristic it is very difficult to detect.
Once a rootkit has been installed, it allows someone to have total remote control of a computer and do things such as files executions and system changes.