Backdoor vs. Rootkit — What's the Difference?

Secret or surreptitious; clandestine

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. The term rootkit is a compound of "root" (the traditional name of the privileged account on Unix-like operating systems) and the word "kit" (which refers to the software components that implement the tool).

Devious or underhanded

A set of software tools used to gain unauthorized access to a computer system on a network and to control its operation.

(Sports) Of or directed toward a player who has slipped behind the opposing defense

(computer security) A set of software tools used by a third party to gain unauthorized access to a computer system and control the system while concealing itself from the user.

An unofficial and often improper entrance or channel

(transitive) To infect (a computer system) with a rootkit.

A means of access to a computer system that allows unauthorized users to circumvent normal authentication procedures.

Alternative spelling of back door, which can be used attributively.

Alternative spelling of back door

Acting from behind and in concealment; backstairs; as, backdoor intrigues.