Run by Berkeley University in the US, SETI@home is a project that offers a free screensaver. Like other screensavers, it starts up when a computer is left unattended and shuts down as soon as the user returns to work. What it does in the interim is unique. It uses the computer's available power to search for extraterrestrial intelligence by analysing chunks of data captured by the world's largest radio telescope. Harnessing the available power of many computers like this is known as grid computing.
However, Dutch computer science student Berend-Jan Wever discovered the potential for accessing the networks of those computers running the screensaver – although he adds that he did not test his theory.
Consequently, the Berkeley team has released a new version of the screensaver to close the security hole.
The team points out that to exploit the vulnerability of earlier versions, "a potential attacker would have to trick the client into contacting a fake server rather than the actual SETI@home server." It adds: "To our knowledge, no SETI@home client has ever been attacked in this manner."