Iranian government officials are saying the country has been subjected to cyber attack again, this time with a virus called Stars.

Gholam Reza Jalali, head of Iran's civilian defense forces, called Passive Defense, issued a statement on the organization's web site. In it, he said the country had been hit with a virus and that Iranian experts were investigating it.

In the statement, Jalali said the virus does little damage in its initial stages and that it is compatible with Iranian systems. He added that it is not yet clear what the virus does.

Outside security experts, such as F-Secure, Sophos and Symantec, have all said they can't verify that the Stars virus is actually anything new as they don't have any examples of the code from Iran. It may be one of several things: a hoax, a common virus that nobody in Iran recognized, or a piece of targeted malicious code.

Many viruses don't target specific computers, but are designed with more generic goals in mind, such as self-replication in which the damage to systems is a byproduct. The same is true of malware that creates botnets; such software doesn't target a specific computer and is more opportunistic (and in fact many users wouldn't even know they are infected).

The Iranian government has not issued any details about kind of damage the Stars virus did. While Jalali did not accuse the U.S. or Israel directly, he did refer to attacks from the U.S. and Israel on Iranian web sites and Internet infrastructure.

This is the second time in the last several months that Iran has reported cyber attacks. A week ago Jalali said German engineering firm Siemens played a role in aiding the cyber attack on Iran's nuclear facilities.

Jalali accused Siemens of helping the United States and Israel launch the Stuxnet worm, which attacks industrial control systems. Stuxnet infects computers via removable drives, such as USB sticks or a CD. It replicates over local networks by exploiting vulnerability in Microsoft server systems.

Evidence emerged that could point to an Israeli origin -- or at least prior knowledge -- of the Stuxnet worm. In February, a retirement party video for Israeli General Gabi Ashkenazi surfaced that noted the successes of the Israeli Defense Forces, and mentioned Stuxnet.

It Iranian officials haven't given details of the damage that Stuxnet did. Symantec, a firm that makes antivirus software, issued a report in February that said one of Stuxnet's targets is centrifuge control systems, which could mean that the virus was intended to disrupt Iran's uranium enrichment program.

Jalali said the consequences of Stuxnet might have been more serious, given that the worm infected computers at the nuclear facilities in Natanz and Busehr.