Once a _____ is installed, the attacker can gain full access to the computer.

• A. rootkit
• B. worm
• C. botnet
• D. zombie

Answer: (A)

A rootkit is designed to provide an attacker with elevated access to a computer while concealing its presence. When a rootkit is successfully installed on a system, it can alter critical system components and functions, allowing the attacker to manipulate the system as if they were the administrator. This level of access means the attacker can install additional malicious software, steal sensitive information, and control the system without detection.

In contrast, a worm is a type of malware that can replicate itself to spread to other computers but does not necessarily provide direct access to the infected system for an attacker. A botnet pertains to a collection of compromised computers controlled by an attacker for various nefarious purposes, but it is not a specific type of malware that guarantees direct access. Similarly, a zombie refers to an individual computer that has been compromised and is under the control of an attacker, usually as part of a botnet, but it does not specifically describe the means by which full access is obtained. Thus, a rootkit uniquely fulfills the requirement of granting full access to a computer once installed.