A report from content delivery network provider Akamai has found that a lot of internet attack traffic comes from Japan:

Japan accounted for 30% of all attack traffic monitored worldwide for the second quarter of 2008, according to a new study issued by content delivery network provider Akamai. The study, which was conducted by monitoring Akamai’s global network of more than 30,000 servers, measured distributed denial-of-service attacks, Web site hacking attempts and DNS hijackings for 139 countries around the world. The United States had the second-highest percentage of attack traffic for the second quarter, at 21.5%, while China came in third at 16.8%.

More details at Network World.