With China's economy cooling down, some of the country's IT professionals are turning to cybercrime, according to a Beijing-based security expert.

Speaking at the CanSecWest security conference last week, Wei Zhao, CEO of Knownsec, a Beijing security company, said that while many Chinese workers may be feeling hard times, business is still booming in the country's cybercrime industry. "As the stock market dropped like a stone, a lot of IT professionals lost lots of money on the stock market," he said. "So sometimes they sell 0days," he said, referring to previously unknown software bugs.

"China is not only the world's factory, but also the world's malware factory," Zhao said.

China's red-hot economy has been hit by the global recession, and while the economy is still growing, technology companies such as Intel, Motorola and Lenovo have all laid off employees in China in recent months.

Last December, Chinese hackers found a previously undisclosed 0day vulnerability in Internet Explorer. When employees of Zhao's company inadvertently published details of the bug on a public forum, Microsoft was sent scrambling to patch the issue.

Chinese hackers tend to focus on hacking software that runs on the desktop, rather than the server, because the underground market pays big money for client-side bugs, which are then often used to install malicious software on millions of desktops.

While recently investigating a single, but widespread attack, Zhao's researchers counted more then 4 million infected computers over a one-day period.

China has an estimated 250 million computer users, so attackers can do pretty well targeting only Chinese systems. "We have a huge amount of users and a very big local market," he said.

Hackers have had a lot of success launching widespread 0day attacks against programs like RealPlayer and Adobe Flash, but they have also hit local Chinese programs, including Xunlei, QQ and UUSee.

Security is often little more than an afterthought for local software developers, Zhao said.

"In China you have all this third-party software that's very popular, but which is much less secure than Microsoft software," said Wayne Huang, CEO of Web security consultancy Armorize, which has research labs in Taiwan. Not only are exploits for Chinese programs like QQ much easier to find -- software companies tend to take much longer to patch the exploits. "QQ is not going to be able to react as quickly as Microsoft," he said.

Cyberattacks in the region can be ingenious. Earlier this month, criminals redirected Taiwanese traffic to the tw.msn.com and taiwan.cnet.com Web sites using what's known as a non-blind TCP spoofing attack.