Greetings

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The primary motivational factor behind the creators of malicious software is
MONEY. Malware is used to steal passwords, credit card numbers, bank account numbers and other sensitive data. It is also used to control the millions of infected computers and use them as data harvesting drones or
bots, which can be used for everything from sending spam emails for the profit of the botmaster that controls them to
denial of service attacks on web sites wherein they have many computers access a server simultaneously to block all other traffic from accessing the website, either to hold the site for ransom or for other purposes, such as political agendas. A popular modern infection type known as
rogue software is a piece of malware that installs itself on a user's system, usually after either scaring them into believing they're already infected and pretending to be a legitimate cure for their problem, or without their consent. They use scare tactics to convince the user to purchase their product with the promise that it will clean their system of the infections that were actually put there by either the rogue security software itself, it's creators or one of its reseller affiliates who are trying to sell more licenses for the software to reap the profits.