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01 Nov 2005

Top ten viruses and hoaxes reported to Sophos in October 2005

Record quantities of new malware are reported by Sophos

Sophos, a world leader in protecting businesses against viruses, spyware and spam, has revealed the top ten viruses and hoaxes causing problems for businesses around the world during the month of October 2005.

The report, compiled from Sophos's global network of monitoring stations, reveals that October has seen the biggest increase in virus numbers since its records began - it now identifies and protects against a total of 112,142 viruses, which is an increase of 1,685 on last month. Netsky-P, the worm written by convicted German teenager Sven Jaschan, continues to head up the top ten twenty months after it was first detected. However, Mytob-GH, which first appeared on 16 October 2005, is already in second place and showing no sign of abating. This Mytob variant is well placed to topple Netsky-P from the top of the chart in November.

The top ten viruses in October were as follows:

Position Last
Malware Percentage of reports
Others 45.8%

September's lull in new viruses was short lived, with October's count totalling a record high of 1,685. Sophos experts have revealed that nearly two thirds of the viruses reported to Sophos during the month were versions of the Mytob worm, with the new Mytob-GH and Mytob-EX variants having made a significant impact.

"The unfortunate onslaught of new threats this month is unsurprising as malware authors ramp up their game in their pursuit of hard cash," said Carole Theriault, senior security consultant at Sophos. "The Mytob dynasty continues to grow - attacking networks thick and fast. Users should ensure that their anti-virus protection is regularly updated since this barrage of threats shows no sign of slowing down."

While Netsky-P no longer poses quite such a potent threat to proactive users, it is still at the top of the October chart for the fourth consecutive month, dropping slightly from 18.6% to 17.13% of viruses reported to Sophos.

This month's chart consists of only three virus families - Netsky, Mytob and Zafi, indicating that virus writers are continuing to create variants of established threats, which prove most effective for financial gain.

"There are six variants of the Mytob worm in the October chart, half of which are new entries," continued Theriault. "The creators of Mytob appear to be a gang of virus writers called Hellbot. By having several gang members they can easily issue several different variants in a short space of time."

With this rise in viruses, Sophos's research shows that 1.66%, or one in 60 emails, circulating in October were viral.

In order to minimise exposure to viruses, Sophos recommends that companies deploy a policy at their email gateway which blocks unwanted executable attachments from being sent into their organisation from the outside world. Companies should also run up-to-date anti-virus software, firewalls and install the latest security patches.

The top ten hoaxes reported to Sophos during October 2005 were as follows:

Position Hoax Percentage of reports
1Hotmail hoax
2Meninas da Playboy
3HIV Needles
4Bonsai kitten
5Budweiser frogs screensaver
6A virtual card for you
7Bill Gates fortune
8WTC Survivor
9Jamie Bulger
10Sainsbury's gift vouchers

"The hoax chart has remained fairly static this month, although the HIV Needles hoax has leapt up to number three," said Theriault. "These sick individuals obviously get a kick out of terrifying the general public, and the speed with which this hoax has circulated highlights this genuine fear factor. The Sainsbury's Gift Vouchers hoax, although not as malicious as the HIV hoax, is still a cruel trick that plays on the hopes of shoppers."

Sophos has made available a free, constantly updated information feed for intranets and websites which means users can always find out about the latest viruses and hoaxes.

Graphics of the above top ten virus chart are also available.

About Sophos

More than 100 million users in 150 countries rely on Sophos as the best protection against complex threats and data loss. Sophos is committed to providing complete security solutions that are simple to deploy, manage, and use and that deliver the industry's lowest total cost of ownership. Sophos offers award-winning encryption, endpoint security, web, email, mobile and network security solutions backed by SophosLabs - a global network of threat intelligence centers.

Sophos is headquartered in Boston, US and Oxford, UK. More information is available at