This article, based on a recent attrition.org report, doesn't mention how many hacked sites were due to default passwords, poor administration, etc. The numbers couldn't possibly be not telling the whole story now, could they. "The year 2000 saw Windows NT steaming ahead yet again as the most hacked web server operating system, after a majority of defaced pages were found to be sitting on compromised NT boxes. As NT is one of the most popular options for web servers, it appears that it is attacked most, however a number of companies running web sites on variations of Linux also suffered the embarrassment of defacement.
Defaced web page aggregation service, Attrition.org, provided the statistics. The site maintains snapshots of any pages that are reported to be hacked and is usually the first port of call for any hacker who has just defaced a web site. According to the research carried out between August 1999 and the present day, Windows NT was running on 56 per cent of compromised web servers. Although none of the other operating systems even came close to these figures, perhaps surprisingly, unknown distributions of Linux took second place with 12 per cent of the compromises."
The link for this article located at Internet.com is no longer available.
