F-Secure Security Labs reported that it reviewed messages from Iranian nuclear energy scientists that stated the computer systems at the Natanz and Fordo nuclear facilities were compromised by a computer worm.
The scientists, which the lab confirmed were Iranian, said the Metasploit hacker tool was used to attack and shut down its automated network and Siemens hardware.
"There was also some music playing randomly on several of the workstations during the middle of the night with the volume maxed out," the message, as translated by the lab, read. "I believe it was playing 'Thunderstruck' by AC/DC."
The lab reported it couldn't confirm any of the details, though the e-mail message it translated came from within the Atomic Energy Organization of Iran.
The Stuxnet computer virus disrupted more than 10 percent of Iranian nuclear centrifuges. Stuxnet works by targeting the speed at which specific components in the centrifuge works, causing problems with the rotational speed.
The Iranian National Computer Emergency Response Team recently distributed software to protect against a type of malware dubbed Flame. Iran in April unplugged computer servers from an oil terminal at Kharq Island following a virus outbreak believed to have been caused by the malware.