Introduction

Fears are now growing about internet security since the "denial-of-service" attacks by "hackers" on high-profile sites such as Yahoo, Amazon, Buy, CNN.com and eBay. An attack on the latter in June 1999 was so bad that in the space of five days, eBay lost 26 per cent of its market value. The incidence of hacking is increasing almost as quickly as the number of sites that are being established on the Web, and companies should be careful not to underestimate the serious damage that hackers can cause. Companies incur major financial loss when their sites are hacked, not to mention damaged reputations, which is often irreversible. Hacking is not limited to the web either. In October of 2000, hackers were able to infiltrate Microsoft's network and access source code by sending a "trojan horse" email attachment to a user on the system.