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06 Nov 2006

Sophos reveals "Dirty Dozen" spam producing countries

US increases lead in chart, as English-speaking worm converts PCs into spam-spewing zombies

Sophos, a world leader in IT security, has published its latest report on the top twelve spam relaying countries over the third quarter of 2006.

Sophos experts believe that a possible reason for America's increasing lead in relayed spam when compared to its closest rival, China, is the emergence of over 300 strains of the mass-spammed Stratio worm. The worm, also known as Stration or Warezov, uses a trick dependent on the victim being able to speak English in its attempt to convert innocent PCs into members of a spam botnet.

The top twelve spam relaying countries in July-September 2006 are as follows:

PositionCountryPercentage
1 United States
21.6%
2 China (incl Hong Kong)
13.4%
3 France
6.3%
3 South Korea
6.3%
5 Spain
5.8%
6 Poland
4.8%
7 Brazil
4.7%
8 Italy
4.3%
9 Germany
3.0%
10 Taiwan
2.0%
11 Israel
1.8%
12 Japan
1.7%
Others 24.3%

"Most unsolicited emails are now sent from zombie PCs - computers infected with Trojans, worms and viruses that turn them into spam-spewing bots. In the past hackers were very reliant on operating system vulnerabilities to convert an innocent computer into a zombie - now they are turning back to malware to trick users into running their malicious code, and opening the backdoor to hackers," said Carole Theriault, senior security consultant at Sophos. "Hundreds of new versions of the Stratio worm have helped steadily increase the volume of spam seen travelling across the net."

Elsewhere in the chart, China has managed to decrease the proportion of spam it relays by 6.6% since last quarter. The UK has successfully dropped out of the chart altogether and is currently in 13th position, while Israel has entered for the first time, taking 11th place. Q3 has also seen spammers deploy new tricks to try and fool both users and anti-spam software.

Spammers rely more on images to bypass filters in pump-and-dump scams

The use of spam containing embedded images continued to rise in Q3 and currently accounts for nearly 40% of all spam, the vast majority being used by pump-and-dump stock spam campaigns. This trick gives spammers a better chance of having their messages read, since images can avoid detection by those anti-spam filters that can only analyse textual content. Often, image spam is animated to further help the message bypass the filter. Having multiple layers of images loaded on top of each other adds "noise", which complicates the message by making every one unique.

Levels of image spam in September and October 2006

Day-to-day levels of image spam in September and October 2006.

In another pump-and-dump spam twist, criminals are also spamming companies with email messages that offer to boost their stock price in return for payment. This could not only enable spammers to boost the value of their own share portfolio, but also see them get paid by the businesses they are helping to cheat the stock market.

Spammers deploy new email harvesting techniques

Sophos has also identified new tricks being used to harvest email addresses for spam purposes. The first asks recipients to forward their chain emails for a fake research project, while another campaign encourages users to visit a video tribute website, which then requests their email address in order to view the full video.

"Integrated anti-malware and anti-spam protection is getting the better of illegal spam peddlers - forcing them to get more creative and crooked. However, if people are playing their security cards right, the spammers' efforts will still be in vain," continued Theriault. "What's most surprising is that those behind these intrusive emails continue to take their chances, despite hefty fines and sentences being dealt out to guilty spammers around the world."

Spammers under the legal microscope

Q3 of 2006 has seen some high profile legal action being taken against spammers. In September, the Australian Communications Authority (ACMA) launched an investigation into the activities of a man suspected of sending more than two billion 'Viagra spam' emails, while in the US, action is being taken against two companies accused of sending unsolicited emails about gambling and alcoholic drinks to children. Also in the US, William Bailey, Jr of North Carolina, faces a maximum sentence of 55 years in jail and 2,750,000 US dollars in fines if found guilty of illegally downloading contact details of 80,000 members of the America College of Physicians.

Spam relayed by continent

Asia continues to be the largest source of spam, although the proportion of spam it relays has reduced by 6.1% since Q2 2006. Europe is currently in second position, but is closing the gap having increased the share of spam it produces by 4.8% in the last quarter.

The breakdown of spam relaying by continent in July-September 2006 is as follows:

PositionContinentPercentage
1 Asia
34.1%
2 Europe
31.9%
3 North America
24.2%
4 South America
8.3%
5 Africa
1.0%
6 Australasia
0.5%

Sophos recommends that computer users ensure they keep their security software up-to-date, as well as using a properly configured firewall and installing the latest operating system security patches. Businesses must also look to implement a best practice policy regarding email account usage.

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 www.sophos.com.