The 2005 Semi-Annual Web Security Trends Report issued by Websense Security Labs has highlighted an alarming trend in an increase in the usage of botnets
to conduct large-scale denial-of-service attacks. Botnets (fleets of compromised machines that have software installed which a hacker can use to remotely control each machine, or issue it with instructions) can sometimes comprise hundreds of thousands of compromised machines, which are used for such nefarious tasks as DDOS attacks and spamming. The motivation for such activities has moved away from mere petty vandalism and annoyance, and into making real profits.
The report also highlighted the dangers of other forms of cyber-crime, including spyware, crimeware, phishing, keylogger installations and creating malicious websites.