The alert came following analysis of some malicious code samples received by members of the response team during recent cyber-attacks.
The three dangerous domains are playball.ddns.info, nvedia.ddns.ino and air.dcsvn.org.
Such malicious codes are capable of stealing data and destroying the systems, Nguyen Khac Lich, deputy director of the VNCERT, said.
The VNCERT has requested units specialising in information technology in ministries and agencies, the department of information and technology in localities, and financial and banking organisations to monitor and delete files containing malicious codes to prevent similar attacks.
Instructions on how malicious codes should be handled can be viewed on the VNCERT website www.vncert.gov.vn.
Chinese hackers on July 29 carried out several cyber-attacks on Noi Bai and Tan Son Nhat airports’ websites and the official website of Vietnam Airlines.
The Civil Aviation Authority of Vietnam (CAAV) said the attacks interrupted the airports’ check-in systems, resulting in check-in procedures being handled manually.
The attacks affected more than 100 flights, with dozens of them being delayed. However, flight operations and security systems at the airports remained unharmed, it said.
At a press conference on August 2, Minister of Information and Communications Truong Minh Tuan said Internet users should not click on strange codes to prevent the computer and network from getting infected with malicious viruses.
He also warned the users against provoking hackers to avoid unexpected responses.
