Botmasters usually don
In order to allow them access to the compromised networks, botmasters claim huge amounts of money. Selling and leasing botnets are two illegal operations that bring lots of money to their masters, and that is why malware authors have started creating botnets with the sole purpose of selling them to other interested parties, ready to spread more malware or spam.
Sending commercial spam is one of the most common applications of botnets.The advertised merchandise is usually either illegal or dangerous. For instance, the vast majority of spam messages deal with restricted medicine, such as Viagra, Levitra, Xanax or other controlled drugs that can only be purchased on prescriptions. Other spam messages advertise replicas, an euphemism that covers a wide range of fake products (Rolex watches and designer pieces of jewellery or accessories).Counterfeit software also represents a significant chunk of the spam messages.