The Goner worm, which vnunet.com revealed as hitting UK shores yesterday, has been tagged as one of the fastest spreading viruses this year despite it being unremarkable in its design.

According to antivirus firm MessageLabs, Goner has already taken down the Dow Jones index in the US.

MessageLabs added that it had stopped around 22,000 copies in the last few hours which, at over 100 copies a minute, makes it one of the fastest spreading viruses ever.

It is known that Goner spreads via email and ICQ but, according to Kaspersky Labs, the virus also uses an infected machine to perform an attack on the #pentagonx ICQ channel.

A script included in the worm generates random users on #pentagonx to overload the server. It is not clear why that particular ICQ channel has been attacked, as we have not been able to access it.

Raimond Genes, European president at Trend Micro, said that, although the virus was not complex and "could have been written by a teenager", the fact that it disables security devices such as firewalls "means that it needs a lot of research".

Graham Cluley, senior technology consultant for Sophos, added: "This worm highlights the importance of being suspicious about anything that arrives unexpectedly in your inbox."

Symantec chief researcher Eric Chien said: "People just haven't learnt the lesson. This is a classic double-click scenario. Users are seeing these emails and opening them immediately. It may be getting into the silly season but you can never afford to let your guard down about viruses."