Almost 1,000 Danish websites have been defaced by Islamic hackers protesting about controversial cartoons mocking the Prophet Muhammad.
The attacks typically replace home pages with pro-Islam messages and condemn the publication of the images.
Many of the messages that replaced the home pages on hacked sites simply condemned the publication of the cartoons in Danish newspaper Jyllands-Posten on 30 September 2005. Some messages called for boycotts of Danish goods.
Other messages warned against mocking Muhammad and some told the Danes to expect a violent response.
More than 900 Danish websites have suffered defacement during the wave of attacks, said Mr Preatoni. He added that a further 1600 Western sites have also been attacked and defaced as part of the same protest.
Most of the sites targeted were run by small organisations and companies that do not have dedicated security workers and cannot keep up with the latest alerts and patches for vulnerabilities.