BEIJING - The number of Internet terminals that contracted viruses in China more than doubled month-on-month recently, a national computer security monitor said here Wednesday.

From August to September, the number of infected terminals in China soared from 2.77 million to 6.26 million, the National Computer Network Emergency Response Technical Team/Coordination Center of China (CNCERT/CC) said in a report.

The majority of new infections were caused by Confickers, a type of virus that targets the Microsoft Windows operating system, cracking administrator passwords. Terminals infected by Confickers tend to then pass on the virus to other terminals. Almost 6 million of the terminals infected in September were done so by Confickers, according to the CNCERT/CC.

Of the rest, 460,000 unlucky host IPs fell victim to Trojans and Bots, up 29.2 percent month on month. A Trojan is a software package that appears desirable for the user to run or install, but then infects the user's terminal once they are tricked. Bots are terminals controlled remotely to infect other terminals through email spam.

During the month-long period, 2,227 Chinese websites, including 181 government websites, were tampered with.

Meanwhile, the number of terminal networks defined by the China National Vulnerability Database as vulnerable to new viruses increased by 4.8 percent from August to 528 in September. Among them, 242 were ranked as "serious" and 487 were vulnerable to "long-distance" cyber attacks from outside of the network itself.

CNCERT/CC is a national-level organization that provides major national organizations with computer network security services and technology support in the handling of security incidents.