According to Bkis, traditional viruses belonging to the Worm, Trojan family . often infect by copying itself to a folder on the system, usually the WindowsSystem32 directory. But recent viruses, especially those from China, have overwritten the malicious code on the standard file of the operating system.
Such camouflage deceives most of the antivirus software because no original file recovery mechanism has been overwritten by the virus. So when antivirus, these software also delete the standard file of the operating system (original file), as a result, users have to reinstall the whole computer and may cause data loss.
Mr. Vu Ngoc Son, Chief of Virus Department of Bkis said that Bkav's virus monitoring system has statistics of 92 new virus lines that appeared in October using the overwriting standard file above. These viruses infected 41,600 computers in Vietnam. When the computer is infected with malicious code, users risk losing personal information, password of mailboxes, game accounts and also credit card numbers, bank accounts.
Mr. Son said Bkis's Bkav software was having this antivirus algorithm thoroughly without damaging the OS.