. The Bad Guys"> I. The Bad Guys DDoS (distributed denial-of-service) Attack An electronic assault in which many compromised systems are made to flood a target with requests and overwhelm its capacity.Trojan horse Malicious code that enters computers through innocuous-seeming applications or data files, then attacks the systems from within. Virus A piece of malicious code that causes undesirable events by infecting files, system/boot records, or applications. Worm A malicious file or piece of code that replicates itself over a network, reproducing until it has consumed system resources.