Iran has long contended it is facing a "soft war" from "hostile governments." This consists of attacks on the computer systems in Iran's nuclear facilities.
And according to Bloomberg Businessweek, this war is allegedly showing itself via a computer worm that's shutting down the "automation network" at two of Iran's facilities, and prompting several of the computers to play AC/DC's "Thunderstruck" at maximum volume during the night. Iran is blaming the U.S. and Israel for these and other attacks, as they believe both countries are doing whatever they can to stifle the progress Iran has made in its nuclear program.
The problem with these claims is there's no hard evidence that this is actually taking place. As Mike Hypponen, a computer security expert has pointed out, the U.S. has used AC/DC songs for various purposes linked to intelligence interests in the past, so it's unlikely they'd do something like this, as it would almost certainly give them away.
A case could be made that this is all Iran's desperate attempt to pressure the U.N. into helping protect the very systems Iran uses for nuclear technology. After all, Iran followed their announcement about AC/DC songs by calling on the U.N. to intervene and condemn "organized cyber attacks against nations."