Australia appears to be hardest hit worldwide by a cunning virus that comes with the subject "Homepage" and takes unsuspecting victims to one of four pornographic Web sites.

This latest virus, which had penetrated just two Australian companies by 10 o'clock this morning, has since spread rapidly. Within four hours, more than 40 local companies had been hit.

The vbs_homepage.a virus comes with the message "Hi - you've got to see this page, it's really cool" but when the attachment is executed, recipients are confronted by a random page from one of four porn Web sites listed in the virus.

The virus is then sent to everyone in the recipient's address book.

"It seems Australia has been hit the hardest so far," Trend Micro's Andy Liou told ZDNet.

"We were first notified [of the virus] by the US this morning. At the time we gave it a yellow alert, which is a medium alert, because there were reports of it in three continents but only two reports from Australia."

However, just when everything appeared to have died down, companies from all industry sectors, including banking and telecommunications, began reporting the virus, according to Liou.

"What we've seen is that it's very fast spreading," Liou said. "We've been inundated with calls for the last two hours."

Although there is nothing destructive about the virus, Trend Micro says it wouldn't take much for someone to modify it, add a couple of lines and make it destructive.

Furthermore, "the danger with this virus is that for a user who has 'preview' enabled on Outlook Express, just looking at the message will execute the virus," Liou said.

Copyright © 2009 CBS Interactive, a CBS Company. All Rights Reserved.
ZDNET is a registered service mark of CBS Interactive. ZDNET Logo is a service mark of CBS Interactive.