China is host to almost half of the world's malware-infected Web sites.
According to a report released Monday by antivirus company Sophos, China--including Hong Kong--hosted 44.8 percent of the world's infected sites in August 2007. The United States ranked a distant second, hosting 20.8 percent of Web sites that contain malicious code.
The number of infected Web pages has also grown. Sophos said that it detected an average of 5,000 new infected pages each day in the month of August.
The company warned that simply staying clear of sites hosted in the top three countries of China, United States and Russia was not effective in avoiding malware.
Said Carole Theriault, Sophos senior security consultant, in a statement: "While more than three quarters of infected Web pages are hosted in just three countries, that doesn't mean you only get hit if you visit Web sites based in those areas.
"Hackers are hijacking Web sites around the world to make them point to malware on sites based in China, the United States and Russia. Cybercriminals don't discriminate when it comes to targeting the Web," she added.
Sophos also warned against a sharp rise in spam pointing people to these infected sites. Malicious senders, in an attempt to bypass attachment virus scanners, are using messages that direct users to Web sites with malicious code. Computers get infected when users click on the links in the e-mail message.
"Most malware writers...are using spam and the Web to infect users," said Theriault. "Criminals are hard at work trying to slip past filters at the corporate gateway."
June saw a spike in spam hosted on Chinese domains, where the figure rose from almost zero to 450 spam domains.