Where have the worms and viruses gone?—new trends in malware

摘要

Although many new worms and viruses surface every week, they are becoming less widespread than those in previous years. In contrast, bots and botnets are becoming more prolific and troublesome; botnets consisting of hundreds of thousands of bots or even more are not uncommon. Bot writers and botnet operators have numerous motives for engaging in their sordid activity, but the desire to make money has become by far the chief motivator. Meanwhile, the nature of current worms and viruses is also changing considerably—a growing number of them uses instant messaging (IM) to replicate, and worms and viruses that target handheld computing devices are also becoming more prevalent. Bots and botnets pose very elevated levels of risk, risk that needs to be controlled through a variety of security countermeasures.