US government Web sites were a favourite target, and in total US sites had been defaced 4,157 times so far this month, followed by Brazil (835), the UK (376), Germany (356) and India (285).
Hackers are finding an increasing number of vulnerabilities in operating systems, server software, applications and libraries deployed on mission-critical systems, making it impossible for systems administrators to patch vulnerabilities without suffering severe downtime.
Although most of the defacements were made on systems running Windows, a significant number of were made on Linux, BSD Unix and Solaris-based machines.
Web site defacements have steadily risen in number from 1998, when there were 269, through 1999 (4,197), 2000 (7,821) and 2001 (31,322).
This year 40,116 defacements had already been recorded by 25 September, leading to projections of 55,000 Web site defacements for the whole of 2002.