Computer truants that combine the characteristics of computer viruses, worms, and malicious code with vulnerabilities found on servers and the Internet. Their purpose is not only to start and transmit an attack but also to spread it by a variety of means. Blended threats are known to spread fast and cause widespread damage—including the launch of a Denial of Service (DoS) attack at a targeted IP address, defacing Web servers, or planting Trojan horse programs to be executed at another time. Blended threats scan for vulnerabilities in systems and then take advantage of the compromised system by, say, embedding code in HTML files on a server, infecting newcomers to a compromised Website, or sending email that is unauthorized from compromised servers and having a worm attachment. Security solutions that use a variety of combined technologies on more than one layer can provide protection from blended threats.

See Also: Code or Source Code; Denial of Service (DoS); HTML or HyperText Markup Language; Internet; Malicious Code; Trojan; Virus; Worm.