CYBER criminals are using popular web phone service Skype to install a password-stealing virus onto unsuspecting people’s computers.

More than 1000 Australians have received the ”Dorkbot” malware virus in the past two days, making us one of the hardest hit countries in the world.

The vast majority of the attacks occurred in Japan (81 per cent), with the US (3.2 per cent) and Australia (2.9 per cent) next on the targeted list.

The malware is a “multi-tasking” worm virus designed to steal people’s usernames and passwords for social networking sites such as Facebook, Twitter, Google and PayPal.

It can also install what is known as “ransomware” – locking people out of their machine and threatening to delete all their files unless they surrender $200 within 48 hours.

On top of all that the virus can also use people’s computers to perform DOS (denial of service) attacks on websites, as well as download further malware onto the same PC.

The virus is installed when users click on a URL in a message seemingly sent by someone on their Skype contact list that reads: “lol is this your new profile pic? [malicious URL]”.

Adam Biviano, senior manager of strategic products at anti-virus company Trend Micro, advised users to be on guard when receiving direct messages on Skype.

“If you haven’t changed your profile picture recently, you need to ask yourself why your friend is sending this message,” he said.

“The other point is if you’re not discussing a particular website and your friend sends you a URL out of the blue or mid conversation, it’s another reason to ask why this person is sending you the link.”

Mr Biviano said the ”Dorkbot” virus was a very basic scheme that cashed in on Skype’s solid reputation for providing a good service.

“The thing with Skype is it’s not commonly attacked,” he said.

“Therefore the social engineering attack becomes more powerful because you’re not expecting malware to be transmitted through Sykpe so you may be more inclined to click on a link a friend sent you.”

A spokesperson for Skype told News Ltd it was aware of the malicious activity and was working quickly to mitigate its impact.

“We strongly recommend upgrading to the newest Skype version and applying updated security features on your computer,” the spokesperson said.

People are also advised not to follow links – even from contacts – that look strange or are unexpected.