Once again, the United States ranks first in the top-12 spam-relaying countries, an Internet threat-management company says, while Canada doesn't even rate.
Security experts at Sophos, based in Burlington, Mass., say that during the third quarter of 2006, the United States has not only maintained it lead, but extended it since the last ranking, during the second quarter of the year.
Second-place China, including Hong Kong, helped the U.S. position by decreasing the amount of spam it relays by nearly 7 per cent since the last quarter.
Relaying is a process by which spammers use infected computers to send their spam. The spammers do not necessarily live in the countries that relay the messages.
The last position on the top-12 list is held by Japan, which accounts for a mere 1.7 per cent of relayed spam. Canada is ranked somewhat lower than even that.
A new entry on the list is Israel, which took 11th spot, with 1.8 per cent of thre world's relayed spam.
Sophos experts suggest that dramatic lead of the United States ahead of the bulk of the list is due to the emergence of more than 300 Stratio worm strains. The mass-spammed worm, also known as Stration or Warezov, is dependent on the victim speaking English as it attempts to convert innocent PCs into members of a spam botnet.
The top 12 spam relaying countries during the July to September period are as follows:
United States (21.6 per cent)
China (13.4 per cent)
France (6.3 per cent)
South Korea (6.3 per cent)
Spain (5.8 per cent)
Poland (4.8 per cent)
Brazil (4.7 per cent)
Italy (4.3 per cent)
Germany (3 per cent)
Taiwan (2 per cent)
Israel (1.8 per cent)
Japan (1.7 per cent)
All others (24.3 per cent)
"Most hackers attack through unsolicited e-mail, sent through a zombie PC, which is a set of computers that become spam-spewing bots when infected with Trojans, worms and viruses," Sophos senior security analyst Ron O'Brien said in a statement.
"In the past, hackers had relied on vulnerabilities in the operating system to convert clean machines into zombies," he said. "However, recently we have witnessed the resurgence of malware in this process. Hackers are using it to trick users into running malicious code and opening the back door of the network to vulnerabilities. ... The steady increase in the volume of spam seen travelling across the Net is directly related to the enormous rise in Stratio worm strains in recent months."
Asia is the major source of spam relaying as counted by continental means, with 34.1 per cent. Europe counts for 31.9 per cent, North America for 24.2 per cent, South America for 8.3 per cent, Africa for 1 per cent and Australasia for 0.5 per cent.
E-mail containing embedded images continue to rise, accounting for nearly 40 per cent of all spam, the vast majority of them fuelling pump-and-dump stock scams. The use of images, static and animated, gives spammers a better chance of bypassing threat detection as images can successfully navigate past anti-spam filters that analyze only text. Spammers also layer images in a single e-mail, thus creating "noise" that aids in avoiding detection.
