A rootkit is a type of malware that enables remote control of a user’s computer without their knowledge. Once a computer has been infected it becomes part of a botnet, the goal of which is to create a network of infected computers that can be used by cyber-thieves to do their bidding.
A botnet is made up of computers that have been compromised by a malicious program known as a rootkit. These computers are then used to perform tasks without the owner’s consent. The most popular uses of a botnet are sending large volumes of spam email and launching denial of service attacks.