A computer virus known as a worm that has been spreading on computers primarily in Iran, India and Indonesia could be a cyberattack on Iranian nuclear facilities, according to widespread media speculation. Creating such a program, which targets a specific Siemens software system controlling automated activity in large industrial facilities, would have required a large team with experience and actionable intelligence. If a national intelligence agency in fact targeted Iranian nuclear facilities, this would be the first deployment of a cyberweapon reported on in the media. It would also mean that the full details of the operation are not likely ever to be known. The so-called Stuxnet worm first attracted significant attention when Microsoft announced concerns over the situation in a Sept. 13 security bulletin, though various experts in the information technology community had been analyzing it for at least a few months.