What Is a Botnet?Main CharacteristicsKey ComponentsC&C StructureBotnet UsageDistributed Denial of Service AttackClick FraudSpam RelayPay-Per-Install AgentLarge-Scale Information HarvestingInformation ProcessingBotnet Protective MechanismsBulletproof HostingDynamic DNSFast FluxingDomain FluxingThe Fight Against BotnetsThe Technical FrontThe Legal FrontWe’ve CoveredReferences