Specifically, the TTPlayer music player is classified as adware, which is an illegal advertisement-generating software. The program is automatically installed into user computers before changing their homepage into an ad page without their permission.

The TTPlayer installation also silently sets up an executive file named hao123.1.0.0.1097.exe into users’ computers.

The malicious file is in fact a trojan, which secretly hides on the host computer and can automatically download more viruses or malicious files under the request of its creator via a remote connection.

This means TTPlayer and hao123 have opened a ‘backdoor’ for hacking attacks on users’ computers without their notice, and can steal their personal information or infect the machines with other malicious programs.

Similarly, Vietnamese users are required to download a software application called HiPlayer in order to be able to watch streaming videos at Baidu’s ahphim.com. The installation of this player is also given along with a ‘bonus’ -- the hao123 file.

The illegal file installations and backdoor opening of Baidu’s software and services are very dangerous for the host computer systems, according to computer security experts.

“The infected computers are easily subject to remote control, information stealing, or becoming zombie computers in hackers’ distributed denial-of-service attacks, or DDoS,” they said.

Computer users are thus recommended not to install programs with dubious origins, or use internet services which require the installation of extra software. They are also advised to set up anti-virus programs and turn on the firewall on their computer for stronger defense.

Earlier this month, on July 1, Baidu officially launched the social network Baidu Tra Da Quan on the Vietnam market, although they have yet to receive licenses for operation as per law.

The social website is their third product in the country, besides the website category launched six months ago at hao123.com.vn, and the question & answer site at zhidao.baidu.com.vn.