6.2- NetworkingAs more and more systems are connected to local and wide area networks, networks may become a more common medium for viral spread. Of particular interest is the inclusion of networking capabilities in newer 32-bit operating systems. If people typically configure their systems to take advantage of these capabilities, and if that leads to more program sharing on local area networks, it could also increase viral spread in these environments. Currently, these capabilities are used primarily for workgroup computing rather than wide area networking, so the increased spread will result primarily in larger incidents, affecting an entire workgroup instead of a single PC, rather than a large increase in worldwide prevalence. The final trend that bears watching is the rise of the Internet and global computing. This has the ability to increase the virus problem substantially over time. There have been incidents of DOS viruses being transmitted on the Internet. Sometimes, they are posted to Internet newsgroups, which function much like bulletin board systems for anyone on the Internet. When the infected programs are downloaded and run, they can infect your PC just like any other infected program. So far, vigilance and rapid action have spread the word about infected programs in newsgroups quickly, and eliminated the problems as they have occurred. The Internet can be used to support wide-area file servers. These are much like file servers on a LAN, but they can be accessed globally. A virus can spread to files on a LAN-based file server, and from there to the other client systems attached to the server. Similar, systems that run programs from wide-area file servers can become infected if the programs on the server are susceptible to infection. While boot viruses could be transmitted on the Internet as diskette images, which would be downloaded and installed onto diskettes, this seems unlikely to become a common means of transporting information. As more information is exchanged over the Internet instead of on diskettes, and the use of diskettes decreases, we would expect a decrease in the prevalence of DOS boot viruses. We would expect that the increased use of the Internet to interchange and access programs would promote an increase in the prevalence of DOS file viruses. There have been a few incidents of viruses and worms that are specifically designed to use world-wide networks to spread [7, 8, 9, 10]. These provide dramatic examples of how quickly and how widely viruses can spread on such networks. Fortunately, while these incidents have been rapid and large, they did not usually recur. After a matter of hours or days, when the virus was eliminated from the network and increased defenses put into place, the virus did not continue to spread. Unlike DOS viruses, which have continued to spread around the world for years, Internet viruses have (so far!) been episodic -- they come, and then they go. But this need not always be the case.
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