A website associated with the Large Hadron Collider (LHC) atom-smashing experiment at Cern has been hacked.
A group of hackers called the GST, or Greek Security Team, has claimed responsibility for the attack. They posted a lengthy message on the site to prove they had breached computer security.
The hackers signed off their message with the words, "We are 2600 - don't mess with us."
Graham Cluley, senior technology consultant at web security firm Sophos, said, "With the huge amount of interest worldwide in the LHC, the thought that hackers were able to compromise and change data on a website is highly disturbing.
"Theoretically, hackers could have planted malicious code, which could have stolen identities or installed malware onto the computers of millions of web visitors."
But, he joked, "Fortunately, there's no evidence as far as we can ascertain that the Greek Security Team planted a Trojan horse."
Cern has disconnected the affected website from the internet while it irons out the security problems. The site is still currently down.