The US hosted more than one third of the websites containing malicious code identified during 2006. The country also relayed more spam than any other nation last year, according to a study by net security firm Sophos.
Sophos's Security Threat Report 2007 reveals that the US hosts 34.2 per cent of malware sample detected last year, closely followed by China (31 per cent of samples). Russia (9.5 per cent of malicious code samples), the Netherlands (4.7 per cent) and the Ukraine (3.2 per cent) are also contributing to the growing problem of the use of hacker-controlled websites to infect surfers. The UK ranked 19th in the chart, with UK-based website hosting 0.5 per cent of all websites containing malicious code.
The number of websites being infected with malware is on the rise, Sophos is currently uncovering an average of 5,000 new URLs hosting malicious code every day, as virus writers are increasingly turning to so-called drive-by-downloads as an alternative to infected email traffic as a preferred means of distributing their wares. The proportion of malware-infected emails fell from one in 44 during 2005 to one in 337 during 2006.
Nearly a third (30 per cent) of malware samples detected by Sophos last year were written in China, according to Sophos. Many of these samples were Trojan horses designed to compromise users' PCs. Around one in six malware strains originating in China are specifically designed to steal passwords from online gamers. By contrast, VXers based in Brazil are responsible for 14.2 per cent of all malware, the majority of which is designed to steal online banking credentials.
Sophos detected 41,536 new pieces of malware in 2006, bringing the total number of malware strains its technology detects to 207,684. Of these new threats, Trojans outnumbered Windows viruses and worms by four to one.
In addition to hosting the largest number of malicious websites, the US continues to top the list of worst spam-relaying nations. Although the country has made progress, 22 per cent of spam messages polluting the internet can be traced back to US machines, a factor largely blamed on widespread infestation of home computers by malware. China (15.9 per cent) and South Korea (7.4 per cent) occupy second and third berths, respectively, in this league of shame.
Sophos reckons up to 90 per cent of all junk mail messages are relayed from zombie computers, compromised machines infected by malware and under the control of hackers. Spammers do not necessarily need to be based in the same country as the infected PCs they use to rely spam, and often aren't, a factor that complicates anti-spam policing efforts. ®