As same as other fields, for point-to-point(P2P) file sharing, there are Japanese counterpart of Kazaa/Limewire/Torrent. Once it was Winny, but after the developer of Winny was prosecuted for making a file sharing application which possibly leads copyrighted material distribution and the development ceased, the open source successor Share took the position of the most popular file sharing platform for Japanese speakers.
Today, on the gigantic bulletin board 2-channel(2chan)’s “Download Ita” [J] (download board), many reports by Share users are observed, their Share process had been accessed more than 20 requests simultaneously from servers on Amazon EC2 cloud, resulted in the process freeze.
On 2 channel, it is said that this flood of access paralyses Share network, many Share clients likely went down.
There are a lot of discussion threads are up on several different boards on 2chan (it is hard to keep those URLs, as 2ch thread stops after 1000 messages and then stored into archive servers, you have to seek the next thread manually), and users are sharing info such like blocking Amazon EC2 IP addresses, applying anti SYN-floot patch, etc. However, as not all file sharing users are computer experts, if this type of flooding access continues it is possible that the Share P2P network will be shrunk.
No attackers nor his/her intention remain unclear yet.