Someone posted hundreds of flashing images and links to more pulsating images on the Epilepsy Foundation site, triggering severe migraines and near seizures for some visitors recently, the Associated Press reports.

The recent attack was likely designed to cause seizures given that it is common knowledge that exposure to flickering images, such as those in video games and cartoons, can bring on such problems in people with photosensitive epilepsy, the foundation said.

Hackers exploited a security hole in the site's publishing software that allowed them to make numerous posts quickly in the support forum. Since the attack, policies have been changed so that visitors can't post animated images or create direct links to other sites, the report says. The FBI also is investigating the matter.

Web site attackers have also targeted the blind, releasing malicious code earlier this year that disabled text-to-speech software used by Web sites for the visually impaired. Researchers believe that attack was designed to cripple computers running illegal copies of the software.