Security intelligence experts have detected the tell-tale signs of organized crime gangs and government espionage in attacks. The resulting increase in attack sophistication means that companies must adopt a more vigilant and correspondingly sophisticated approach to defending their environments. In the last couple of years, there has been an explosion in the number of attacks that start by infecting home computers connected to the Internet with specific malware. These networks of infected machines are often known as “zombie bot networks” or “botnets” and hackers then take control of these machines and use them to send spam, phishing messages, or launch distributed denial of service attacks on Web sites.”]