The entire computer network of the Russian stock exchange was shut down on Thursday as IT administrators tried to contain a virus outbreak. A computer that was connected to the Internet was infected and then started launching a denial of service attack against other machines on the network. The computer was infected by what appears to be a custom made virus - one that specifically targeted the stock exchange.
The infected computer, which was on a test trading network, started flooding the network with large amounts of data. The traffic overloaded the network routers and caused administrators to take everything offline for about an hour. Administrators had been expecting an attack from another worm, the Nyxem or as some call it the Kama Sutra worm, but that attack didn't materialize.