Learn What To Fear, And Then Get Some Protection
The first and perhaps most important step in constructing a network security strategy is understanding precisely what must be defended, and what it must be defended against.The first and perhaps most important step in constructing a network security strategy is understanding precisely what must be defended, and what it must be defended against. Every enterprise is different in this regard; one companys survival may rely entirely on keeping certain information secret, while another may be indifferent to data security so long as its servers remain online and accessible by the public. Without a clear set of priorities specific to a given network, administrators are forced to spread their resources thin, leaving unimportant targets overdefended and critical ones vulnerable. Defacement is an attack designed to alter or replace data in a Web page. Defacements are among the easiest attacks to pull off and are obvious to the public; as a result, they are very common, widely publicized and greatly feared. In practice, however, they cause little or no damage to network functionality and are extremely easy to repair. In essence, they amount to the online equivalent of graffitiannoying and ugly, but not a serious threat.
A denial of service (DOS) attack attempts to block legitimate users from accessing network resources. DOS attacks came to the publics attention in February 2000 when a Canadian teenager effectively knocked a number of high-profile Web sites off-line by flooding them with spurious traffic; similarly, the "Code Red" worm, "Melissa" and the "Love Bug" did most of their damage by tying up network bandwidth and e-mail or Web servers. While they are often disruptive and costly, DOS attacks tend to be short-lived and restricted to services easily accessible by the public. As a result, they are primarily a threat to time-sensitive transactions or services that require extremely high availability.