The site of the Estonian security monitoring and defacement archiving firm (zone-h.org) has been replaced by a "screw you" message by a gang of defacers from Saudi Arabia. At the time of writing, the site is yet to be rebuilt.
The techniques used in the attacks are unclear. Zone-h has been active in chronicling politically motivated hacks by Islamic hackers, and others, in the past. This might have provided the motive for the attack. On the other hand, the assault might simply have been conceived as a means to gain kudos in the digital underground by its perps, Devil Hacker & Unix Web.
As far as we're aware, Zone-h has never been defaced before. From time to time other defacement archives have been subject to denial of service attacks so the attack on Zone-h, by far the best known defacement archive, doesn't come as a tremendous surprise.
Zone-h's site runs an Apache web server on a Unix platform, Netcraft Reports Source